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Biological processes in the human body are regulated through complex and precise arrangements of cell structures and their interactions. In vivo models serve as the most accurate choice for biological studies to understand these processes. However, they are costly, time-consuming, and raise ethical issues. Microphysiological systems have been developed to create advanced in vitro models that mimic in vivo-like microenvironments. They are often combined with integrated sensing technologies to perform real-time measurements to gain additional information. However, conventional sensing electrodes, made of inorganic materials such as gold or platinum, differ fundamentally from biological materials. Organic bioelectronic devices made from conjugated polymers are promising alternatives for biological sensing applications and aim to improve the interconnection between abiotic electronics and biotic materials. The widespread use of these devices is partly hindered by the limited availability of materials and low-cost fabrication methods. In this thesis, we provide new tools and materials that facilitate the use of organic bioelectronic devices for in vitro sensing applications. We developed a method to pattern the conducting polymer poly(3,4‑ethylenedioxythiophene) polystyrene sulfonate and to fabricate organic microelectronic devices using wax printing, filtering, and tape transfer. The method is low-cost, time-effective, and compatible with in vitro cell culture models. To achieve higher resolution, we further developed a patterning method using femtosecond laser ablation to fabricate organic electronic devices such as complementary inverters or biosensors. The method is maskless and independent of the type of conjugated polymer. Besides fabrication processes, we introduced a newly synthesized material, the semiconducting conjugated polymer p(g42T‑T)‑8%OH. This polymer contains hydroxylated side chains that enable surface modifications, allowing control of cell adhesion., Biologiska processer i människokroppen regleras genom komplexa och exakta arrangemang av cellstrukturer och deras interaktioner. In vivo modeller är det mest exakta valet för biologiska studier för att förstå dessa processer. Men de är dyra, tidskrävande och behäftade med etiska dilemman. Mikrofysiologiska system har utvecklats för att skapa avancerade in vitro-modeller för att efterlikna mikromiljöer som finns in vivo. Dessa system kombineras ofta med integrerade sensortekniker för att utföra mätningar i realtid för att få ytterligare information. Konventionella elektroder, gjorda av oorganiska material som guld eller platina, skiljer sig dock fundamentalt från biologiska material. Organiska bioelektroniska komponenter tillverkade av konjugerade polymerer är intressanta alternativ för biologiska sensortillämpningar eftersom de har potential att förbättra sammankopplingen mellan abiotisk elektronik och biotiska material. Deras användning hindras delvis av den begränsade tillgången på material och billiga tillverkningsmetoder. I den här avhandlingen tillhandahåller vi nya verktyg och material som underlättar användningen av organiska bioelektroniska komponenter för in vitro avkänningstillämpningar. Vi utvecklade en metod för att mönstra den ledande polymeren poly(3,4-etylendioxitiofen) polystyrensulfonat och tillverka organiska mikroelektroniska komponenter med hjälp av vaxtryck, filtrering och tejpöverföring. Metoden har låg kostnad, är tidseffektiv och kompatibel med in vitro cellodlingsmodeller. För att uppnå högre upplösning vidareutvecklade vi en mönstringsmetod med femtosekundlaserablation för att tillverka organiska elektroniska enheter såsom komplementära växelriktare eller biosensorer. Metoden involverar inga masker och är inte beroende av typen av konjugerad polymer. Förutom tillverkningsprocesser introducerade vi ett nytt material, den konjugerade polymeren p(g42T‑T)‑8%OH. Denna polymer innehåller hydroxylerade sidokedjor som möjliggör ytmodifieringar, vil, QC 2024-02-06

Organic electrochemical transistors (OECTs) are of great interest in low-power bioelectronics and neuromorphic computing, as they utilize organic mixed ionic-electronic conductors (OMIECs) to transduce ionic signals into electrical signals. However, the poor environmental stability of OMIEC materials significantly restricts the practical application of OECTs. Therefore, the non-fused planar naphthalenediimide (NDI)-dialkoxybithiazole (2Tz) copolymers are fine-tuned through varying ethylene glycol (EG) side chain lengths from tri(ethylene glycol) to hexa(ethylene glycol) (namely P-XO, X = 3–6) to achieve OECTs with high-stability and low threshold voltage. As a result, the NDI-2Tz copolymers exhibit ambipolarity, rapid response (<10 ms), and ultra-high n-type stability. Notably, the P-6O copolymers display a threshold voltage as low as 0.27 V. They can operate in n-type mode in an aqueous solution for over 60 h, maintaining an on-off ratio of over 105. This work sheds light on the design of exceptional n-type/ambipolar materials for OECTs. It demonstrates the potential of incorporating these ambipolar polymers into water-operational integrated circuits for long-term biosensing systems and energy-efficient brain-inspired computing.

Organic electrochemical transistors (OECTs) are one of the promising building blocks to realize next-generation bioelectronics. To date, however, the performance and signal processing capabilities of these devices remain limited by their stability and speed. Herein, the authors demonstrate stable and fast n-type organic electrochemical transistors based on a side-chain-free ladder polymer, poly(benzimidazoanthradiisoquinolinedione). The device demonstrated fast normalized transient speed of 0.56 ± 0.17 ms um−2 and excellent long-term stability in aqueous electrolytes, with no significant drop in its doping current after 50 000 successive doping/dedoping cycles and 2-month storage at ambient conditions. These unique characteristics make this polymer especially suitable for bioelectronics, such as being used as a pull-down channel in a complementary inverter for long-term stable detection of electrophysiological signals. Moreover, the developed device shows a reversible anti-ambipolar behavior, enabling reconfigurable electronics to be realized using a single material. These results go beyond the conventional OECT and demonstrate the potential of OECTs to exhibit dynamically configurable functionalities for next-generation reconfigurable electronics. © 2024 Wiley-VCH GmbH.

Organic electrochemical transistors (OECTs) based complementary inverters have been considered as promising candidates in electrophysiological amplification, owing to their low power consumption, and high gain. To create complementary inverters, it is important to use highly stable p-type and n-type polymers with well-balanced current. In this study, the electrochemical stability of p-type ladder-conjugated polymer-based OECT is improved through an annealing process that maintains its doped-state drain current from 76% to 105% after 4,500 cycles in ambient environment. Next an OECT-based complementary inverter made from p-type and n-type ladder-conjugated polymers (PBBTL and BBL) that possess ultra-low power consumption (≈170 nW), high gain (67 V/V), and high noise margin (92%) with full rail-to-rail swing, is presented. Furthermore, its potential for amplifying the envelope of surface electromyography (EMG) for robotic hand control is demonstrated. The high variation in the output (0.35 V) allows the amplified EMG signals to be directly captured by a commercial analog-to-digital converter, which in turn controls the robot hand to grasp different objects with low delay and low noise. These results demonstrate the capability of OECT inverter-based amplifier in future signal processing-free human-machine interface, particularly useful for prosthetic control and gesture control applications. © 2023 Wiley-VCH GmbH.

The development of soft and flexible devices for collection of bioelectrical signals is gaining momentum for wearable and implantable applications. Among these devices, organic electrochemical transistors (OECTs) stand out due to their low operating voltage and large signal amplification capable of transducing weak biological signals. While liquid electrolytes have demonstrated efficacy in OECTs, they limit its operating temperature and pose challenges for electronic packaging due to potential leakage. Conversely, solid electrolytes offer advantages such as mechanical flexibility, robustness against environmental factors, and ability to bridge the interface between rigid dry electronics systems and soft wet biological tissues. However, few systems have demonstrated generality and compatibility with a wide range of state-of-the-art organic mixed ionic-electronic conductors (OMIECs). This paper introduces a highly stretchable, flexible, biocompatible, self-healable gelatin-based solid-state electrolyte, compatible with both p- and n-type OMIEC channels while maintaining high performance and excellent stability. Furthermore, this nonvolatile electrolyte is stable up to 120 °C and exhibits high ionic conductivity even in dry environment. Additionally, an OECT-based complementary inverter with a record-high normalized-gain of 228 V−1 and a corresponding ultralow static power consumption of 1 nW is demonstrated. These advancements pave the way for versatile applications ranging from bioelectronics to power-efficient implants. © 2024 The Author(s). Advanced Materials published by Wiley-VCH GmbH.

Currently, silicon-based electronic devices dominate our technology landscape, significantly enhancing human life and realizing various technological possibilities. However, we are transitioning into an era where carbon-based organic electronic devices are gaining prominence. This shift was enabled by the groundbreaking discovery that polymers, previously regarded as insulators, can exhibit electrical conductivity. Since then, research has advanced significantly in the development of electronic devices utilizing conductive polymers and organic semiconductors. The semiconductor and conductive properties of these organic materials are heavily influenced by the degree of doping. While research has primarily focused on doping methods using various dopants, challenges related to stability and uniformity have emerged. To address these issues, conjugated polyelectrolytes (CPEs) with self-doping capabilities have been developed. These materials incorporate functional groups directly into the polymer structure, eliminating the need for external dopants. This advancement has enhanced their performance as both active layers and interface layers in organic devices, and their potential applications as biosensors are particularly promising. Despite progress in the field, a comprehensive understanding of complex donor-acceptor (D-A) type CPEs remains limited. This dissertation explores the design and application of D-A type self-doping CPEs. We systematically synthesized various D-A CPEs with different electron acceptor groups and investigated their optical and electronical properties. Our analysis revealed that these properties are predominantly influenced by the molecular structure, with experimental results aligning well with theoretical calculations. A notable finding was the significant variation in self-doping levels between two CPEs with similar energy levels. Simulation-based analysis of the protonation step's Gibbs free energy provided insights into this discrepancy, sugg

In the domain of conventional electronics which are integrated into our daily lives, electrons predominantly serve as charge carriers. In contrast, biological systems primarily utilize ions and molecules of various sizes for signal transmission. This communication gap has been effectively bridged by the advent of conducting and semiconducting organic polymers, which uniquely exhibit combined electronic and ionic conductivity. These materials have become invaluable in translating signals between electronic and biological systems, giving rise to the field of organic bioelectronics. This field now offers a flexible platform that develops tools for biological recording and regulation, with potential applications extending from life sciences to clinical applications. This thesis explores advancements in organic bioelectronics, focusing on the development of organic electrochemical transistors (OECTs) based on conducting polymers and the development of organic conductors composed of conductive hydrogels, through controlled polymerization of tri-thiophene monomers. We began by investigating the electrically driven polymerization of the water-soluble tri-thiophene monomer called ETE-S. Our analysis demonstrates how alterations in monomer concentrations can affect the monomer aggregation in solution and the electrical properties of the resultant conducting polymer films, which are crucial for the potential development of neuromorphic devices and other bioelectronic applications. Additionally, we investigated the electrically driven copolymerization of the water-soluble tri-thiophene monomers with two distinct sidechains, including ETE-S and ETE-PC. This study demonstrated that the onset potential of electropolymerization process and threshold voltage of the resultant OECT devices can be influenced by regulating monomer blend ratios, thereby enhancing the functionality of OECTs for bioelectronic applications. Furthermore, enzymatic polymerization of a water-soluble tri, Inom konventionell elektronik, som är integrerad i vårt dagliga liv, fungerar elektroner huvudsakligen som laddningsbärare. I biologiska system används däremot främst joner och molekyler av olika storlekar för signalöverföring. Denna kommunikationsklyfta har effektivt överbryggats genom tillkomsten av ledande och halvledande organiska polymerer, som på ett unikt sätt uppvisar kombinerad elektronisk och jonisk ledningsförmåga. Dessa material har blivit ovärderliga när det gäller att överföra signaler mellan elektroniska och biologiska system, vilket har gett upphov till området organisk bioelektronik. Detta område erbjuder nu en flexibel plattform som utvecklar verktyg för biologisk registrering och reglering, med potentiella tillämpningar som sträcker sig från biovetenskap till kliniska tillämpningar. Denna avhandling utforskar framsteg inom organisk bioelektronik, med fokus på utvecklingen av organiska elektrokemiska transistorer (OECTs) baserade på ledande polymerer och utvecklingen av organiska ledare bestående av ledande hydrogeler, genom kontrollerad polymerisation av tritiofenmonomerer. Vi började med att undersöka den elektriskt drivna polymerisationen av den vattenlösliga tritiofenmonomeren ETE-S. Vår analys visar hur förändringar i monomerkoncentrationer kan påverka monomeraggregeringen i lösning och de elektriska egenskaperna hos de resulterande ledande polymerfilmerna, vilket är avgörande för den potentiella utvecklingen av neuromorfiska enheter och andra bioelektroniska applikationer. Dessutom undersökte vi den elektriskt drivna sampolymerisationen av de vattenlösliga tritiofenmonomererna med två distinkta sidokedjor, inklusive ETE-S och ETE-PC. Denna studie visade att startpotentialen för elektropolymeriseringsprocessen och tröskelspänningen för de resulterande OECT-enheterna kan påverkas genom att reglera monomerblandningsförhållandena, vilket förbättrar funktionaliteten hos OECT för bioelektroniska applikationer. Vidare användes enzymatisk polyme

In the domain of conventional electronics which are integrated into our daily lives, electrons predominantly serve as charge carriers. In contrast, biological systems primarily utilize ions and molecules of various sizes for signal transmission. This communication gap has been effectively bridged by the advent of conducting and semiconducting organic polymers, which uniquely exhibit combined electronic and ionic conductivity. These materials have become invaluable in translating signals between electronic and biological systems, giving rise to the field of organic bioelectronics. This field now offers a flexible platform that develops tools for biological recording and regulation, with potential applications extending from life sciences to clinical applications. This thesis explores advancements in organic bioelectronics, focusing on the development of organic electrochemical transistors (OECTs) based on conducting polymers and the development of organic conductors composed of conductive hydrogels, through controlled polymerization of tri-thiophene monomers. We began by investigating the electrically driven polymerization of the water-soluble tri-thiophene monomer called ETE-S. Our analysis demonstrates how alterations in monomer concentrations can affect the monomer aggregation in solution and the electrical properties of the resultant conducting polymer films, which are crucial for the potential development of neuromorphic devices and other bioelectronic applications. Additionally, we investigated the electrically driven copolymerization of the water-soluble tri-thiophene monomers with two distinct sidechains, including ETE-S and ETE-PC. This study demonstrated that the onset potential of electropolymerization process and threshold voltage of the resultant OECT devices can be influenced by regulating monomer blend ratios, thereby enhancing the functionality of OECTs for bioelectronic applications. Furthermore, enzymatic polymerization of a water-soluble tri, Inom konventionell elektronik, som är integrerad i vårt dagliga liv, fungerar elektroner huvudsakligen som laddningsbärare. I biologiska system används däremot främst joner och molekyler av olika storlekar för signalöverföring. Denna kommunikationsklyfta har effektivt överbryggats genom tillkomsten av ledande och halvledande organiska polymerer, som på ett unikt sätt uppvisar kombinerad elektronisk och jonisk ledningsförmåga. Dessa material har blivit ovärderliga när det gäller att överföra signaler mellan elektroniska och biologiska system, vilket har gett upphov till området organisk bioelektronik. Detta område erbjuder nu en flexibel plattform som utvecklar verktyg för biologisk registrering och reglering, med potentiella tillämpningar som sträcker sig från biovetenskap till kliniska tillämpningar. Denna avhandling utforskar framsteg inom organisk bioelektronik, med fokus på utvecklingen av organiska elektrokemiska transistorer (OECTs) baserade på ledande polymerer och utvecklingen av organiska ledare bestående av ledande hydrogeler, genom kontrollerad polymerisation av tritiofenmonomerer. Vi började med att undersöka den elektriskt drivna polymerisationen av den vattenlösliga tritiofenmonomeren ETE-S. Vår analys visar hur förändringar i monomerkoncentrationer kan påverka monomeraggregeringen i lösning och de elektriska egenskaperna hos de resulterande ledande polymerfilmerna, vilket är avgörande för den potentiella utvecklingen av neuromorfiska enheter och andra bioelektroniska applikationer. Dessutom undersökte vi den elektriskt drivna sampolymerisationen av de vattenlösliga tritiofenmonomererna med två distinkta sidokedjor, inklusive ETE-S och ETE-PC. Denna studie visade att startpotentialen för elektropolymeriseringsprocessen och tröskelspänningen för de resulterande OECT-enheterna kan påverkas genom att reglera monomerblandningsförhållandena, vilket förbättrar funktionaliteten hos OECT för bioelektroniska applikationer. Vidare användes enzymatisk polyme

Biological processes in the human body are regulated through complex and precise arrangements of cell structures and their interactions. In vivo models serve as the most accurate choice for biological studies to understand these processes. However, they are costly, time-consuming, and raise ethical issues. Microphysiological systems have been developed to create advanced in vitro models that mimic in vivo-like microenvironments. They are often combined with integrated sensing technologies to perform real-time measurements to gain additional information. However, conventional sensing electrodes, made of inorganic materials such as gold or platinum, differ fundamentally from biological materials. Organic bioelectronic devices made from conjugated polymers are promising alternatives for biological sensing applications and aim to improve the interconnection between abiotic electronics and biotic materials. The widespread use of these devices is partly hindered by the limited availability of materials and low-cost fabrication methods. In this thesis, we provide new tools and materials that facilitate the use of organic bioelectronic devices for in vitro sensing applications. We developed a method to pattern the conducting polymer poly(3,4‑ethylenedioxythiophene) polystyrene sulfonate and to fabricate organic microelectronic devices using wax printing, filtering, and tape transfer. The method is low-cost, time-effective, and compatible with in vitro cell culture models. To achieve higher resolution, we further developed a patterning method using femtosecond laser ablation to fabricate organic electronic devices such as complementary inverters or biosensors. The method is maskless and independent of the type of conjugated polymer. Besides fabrication processes, we introduced a newly synthesized material, the semiconducting conjugated polymer p(g42T‑T)‑8%OH. This polymer contains hydroxylated side chains that enable surface modifications, allowing control of cell adhesion., Biologiska processer i människokroppen regleras genom komplexa och exakta arrangemang av cellstrukturer och deras interaktioner. In vivo modeller är det mest exakta valet för biologiska studier för att förstå dessa processer. Men de är dyra, tidskrävande och behäftade med etiska dilemman. Mikrofysiologiska system har utvecklats för att skapa avancerade in vitro-modeller för att efterlikna mikromiljöer som finns in vivo. Dessa system kombineras ofta med integrerade sensortekniker för att utföra mätningar i realtid för att få ytterligare information. Konventionella elektroder, gjorda av oorganiska material som guld eller platina, skiljer sig dock fundamentalt från biologiska material. Organiska bioelektroniska komponenter tillverkade av konjugerade polymerer är intressanta alternativ för biologiska sensortillämpningar eftersom de har potential att förbättra sammankopplingen mellan abiotisk elektronik och biotiska material. Deras användning hindras delvis av den begränsade tillgången på material och billiga tillverkningsmetoder. I den här avhandlingen tillhandahåller vi nya verktyg och material som underlättar användningen av organiska bioelektroniska komponenter för in vitro avkänningstillämpningar. Vi utvecklade en metod för att mönstra den ledande polymeren poly(3,4-etylendioxitiofen) polystyrensulfonat och tillverka organiska mikroelektroniska komponenter med hjälp av vaxtryck, filtrering och tejpöverföring. Metoden har låg kostnad, är tidseffektiv och kompatibel med in vitro cellodlingsmodeller. För att uppnå högre upplösning vidareutvecklade vi en mönstringsmetod med femtosekundlaserablation för att tillverka organiska elektroniska enheter såsom komplementära växelriktare eller biosensorer. Metoden involverar inga masker och är inte beroende av typen av konjugerad polymer. Förutom tillverkningsprocesser introducerade vi ett nytt material, den konjugerade polymeren p(g42T‑T)‑8%OH. Denna polymer innehåller hydroxylerade sidokedjor som möjliggör ytmodifieringar, vil, QC 2024-02-06

In the domain of conventional electronics which are integrated into our daily lives, electrons predominantly serve as charge carriers. In contrast, biological systems primarily utilize ions and molecules of various sizes for signal transmission. This communication gap has been effectively bridged by the advent of conducting and semiconducting organic polymers, which uniquely exhibit combined electronic and ionic conductivity. These materials have become invaluable in translating signals between electronic and biological systems, giving rise to the field of organic bioelectronics. This field now offers a flexible platform that develops tools for biological recording and regulation, with potential applications extending from life sciences to clinical applications. This thesis explores advancements in organic bioelectronics, focusing on the development of organic electrochemical transistors (OECTs) based on conducting polymers and the development of organic conductors composed of conductive hydrogels, through controlled polymerization of tri-thiophene monomers. We began by investigating the electrically driven polymerization of the water-soluble tri-thiophene monomer called ETE-S. Our analysis demonstrates how alterations in monomer concentrations can affect the monomer aggregation in solution and the electrical properties of the resultant conducting polymer films, which are crucial for the potential development of neuromorphic devices and other bioelectronic applications. Additionally, we investigated the electrically driven copolymerization of the water-soluble tri-thiophene monomers with two distinct sidechains, including ETE-S and ETE-PC. This study demonstrated that the onset potential of electropolymerization process and threshold voltage of the resultant OECT devices can be influenced by regulating monomer blend ratios, thereby enhancing the functionality of OECTs for bioelectronic applications. Furthermore, enzymatic polymerization of a water-soluble tri, Inom konventionell elektronik, som är integrerad i vårt dagliga liv, fungerar elektroner huvudsakligen som laddningsbärare. I biologiska system används däremot främst joner och molekyler av olika storlekar för signalöverföring. Denna kommunikationsklyfta har effektivt överbryggats genom tillkomsten av ledande och halvledande organiska polymerer, som på ett unikt sätt uppvisar kombinerad elektronisk och jonisk ledningsförmåga. Dessa material har blivit ovärderliga när det gäller att överföra signaler mellan elektroniska och biologiska system, vilket har gett upphov till området organisk bioelektronik. Detta område erbjuder nu en flexibel plattform som utvecklar verktyg för biologisk registrering och reglering, med potentiella tillämpningar som sträcker sig från biovetenskap till kliniska tillämpningar. Denna avhandling utforskar framsteg inom organisk bioelektronik, med fokus på utvecklingen av organiska elektrokemiska transistorer (OECTs) baserade på ledande polymerer och utvecklingen av organiska ledare bestående av ledande hydrogeler, genom kontrollerad polymerisation av tritiofenmonomerer. Vi började med att undersöka den elektriskt drivna polymerisationen av den vattenlösliga tritiofenmonomeren ETE-S. Vår analys visar hur förändringar i monomerkoncentrationer kan påverka monomeraggregeringen i lösning och de elektriska egenskaperna hos de resulterande ledande polymerfilmerna, vilket är avgörande för den potentiella utvecklingen av neuromorfiska enheter och andra bioelektroniska applikationer. Dessutom undersökte vi den elektriskt drivna sampolymerisationen av de vattenlösliga tritiofenmonomererna med två distinkta sidokedjor, inklusive ETE-S och ETE-PC. Denna studie visade att startpotentialen för elektropolymeriseringsprocessen och tröskelspänningen för de resulterande OECT-enheterna kan påverkas genom att reglera monomerblandningsförhållandena, vilket förbättrar funktionaliteten hos OECT för bioelektroniska applikationer. Vidare användes enzymatisk polyme

Organic mixed ionic-electronic conductors (OMIECs) have emerged as promising materials for biological sensing, owing to their electrochemical activity, stability in an aqueous environment, and biocompatibility. Yet, OMIEC-based sensors rely predominantly on the use of composite matrices to enable stimuli-responsive functionality, which can exhibit issues with intercomponent interfacing. In this study, an approach is presented for non-enzymatic glucose detection by harnessing a newly synthesized functionalized monomer, EDOT-PBA. This monomer integrates electrically conducting and receptor moieties within a single organic component, obviating the need for complex composite preparation. By engineering the conditions for electrodeposition, two distinct polymer film architectures are developed: pristine PEDOT-PBA and molecularly imprinted PEDOT-PBA. Both architectures demonstrated proficient glucose binding and signal transduction capabilities. Notably, the molecularly imprinted polymer (MIP) architecture demonstrated faster stabilization upon glucose uptake while it also enabled a lower limit of detection, lower standard deviation, and a broader linear range in the sensor output signal compared to its non-imprinted counterpart. This material design not only provides a robust and efficient platform for glucose detection but also offers a blueprint for developing selective sensors for a diverse array of target molecules, by tuning the receptor units correspondingly., Bio-Electronics

Neuromorphic computing offers the opportunity to curtail the huge energy demands of modern artificial intelligence (AI) applications by implementing computations into new, brain-inspired computing architectures. However, the lack of fabrication processes able to integrate several computing units into monolithic systems and the need for new, hardware-tailored training algorithms still limit the scope of application and performance of neuromorphic hardware. Recent advancements in the field of organic transistors present new opportunities for neuromorphic systems and smart sensing applications, thanks to their unique properties such as neuromorphic behavior, low-voltage operation, and mixed ionic-electronic conductivity. Organic neuromorphic transistors push the boundaries of energy efficient brain-inspired hardware AI, facilitating decentralized on-chip learning and serving as a foundation for the advancement of closed-loop intelligent systems in the next generation. The biocompatibility and dual ionic-electronic conductivity of organic materials introduce new prospects for biointegration and bioelectronics. Their ability to sense and regulate biosystems, as well as their neuro-inspired functions can be combined with neuromorphic computing to create the next-generation of bioelectronics. These systems will be able to seamlessly interact with biological systems and locally compute biosignals in a relevant matter.

The development and optimization of a paper-based ion-selective organic electrochemical transistor (IS-OECT) with an outstanding analytical performance is presented. The combination of thick-film transistor technology with a suitable optimization of the ion-selective membrane composition and thickness allows reaching sensitivities of up to 2.50 mA/decade, which is more than one order of magnitude higher than other similar devices reported up to date. The system shows good selectivity, allowing the detection of low concentrations of potassium in high saline concentrations, and a linear range from 0.1 mM to 100 mM, which covers the relevant clinical range of K+ in blood. A calibration curve for K+ in artificial serum between 1 and 10 mM shows changes in concentrations down to 0.05 mM can be discriminated. Furthermore, the device can be made with a simple manufacturing process, such as drop casting, on low-cost substrate materials and can be operated with a gate voltage of 0 V. This IS-OCET offers promising avenues for developing ion-sensing platforms for the point of need.

Electrocardiogram (ECG) mapping can provide vital information in sports training and cardiac disease diagnosis. However, most electronic devices for monitoring ECG signals need to use multiple long wires, which limit their wearability and conformability in practical applications, while wearable ECG mapping based on integrated sensor arrays has been rarely reported. Herein, ultra-flexible organic electrochemical transistor (OECT) arrays used for wearable ECG mapping on the skin surface above a human heart are presented. QRS complexes of ECG signals at different recording distances and directions relative to the heart are obtained. Furthermore, the ECG signals are successfully analyzed by the devices before and after exercise, indicating potential applications in some sports training and fitness scenarios. The OECT arrays that can conveniently monitor spacial ECG signals in the heart region may find niche applications in wearable electronics and healthcare products in the future. © 2023 Wiley-VCH GmbH.

This report aims to study the degradation of poly(trimethylene carbonate) (PTMC) caused by the enzyme carboxylesterase in vitro. As well as to characterise polymer blends of f-BTI2g-TVTCN and poly(3-hydroxybutyric acid) as core components for organic electrochemical transistors (OETCs). This is to assess the suitability of these polymers in biodegradable biosensors. The degradation study of PTMC showed a lack of degradation in contrast to previous studies performed on the material; previous studies recorded a mass loss of between (5-8)% after two months. The cause for this discrepancy is still unknown but the evidence points to both systematic faults in the gravimetric analysis as well as random errors found in the equipment. The OECT showed that increasing the PHB fraction in the polymer blend resulted in a higher output. The most stable device consisted of a 1:6 blend of f-BTI2g-TVTCN to PHB. Fewer tests were conducted on the 1:10 blend because two devices were damaged during the experiment. The statistical impact of the smaller sample size cannot be overstated so further testing should be conducted to verify the results.

Organic ionic/electronic conductors (OMIECs) offer a promising alternative to metals and inorganic semiconductors for direct interfacing between human-made electronics and biological tissues. A device that takes advantage of the mixed ionic/electronic conductivity of OMIEC materials is the organic electrochemical transistor (OECT). High-density OECTs are typically fabricated using costly cleanroom-based lithography and complex lift-off processes. To simplify the fabrication of OECTs, we propose laser direct writing of conjugated polymers using a commercial two-photon polymerization 3D printer. Ultrafast laser direct writing allows single-digit micrometer resolution and high-speed processing, thereby enabling a cost-effective and simple fabrication process., QC 20240605Part of ISBN 978-488686435-2

Microfluidic surface chemistry can enable control of capillary-driven flow without the need for bulky external instrumentation. A novel pondered nonhomogeneous coating defines regions with different wetting properties on the microchannel walls. It changes the curvature of the liquid–air meniscus at various channel cross-sections and consequently leads to different capillary pressures, which is favorable in the strive toward automatic flow control. This is accomplished by the deposition of hydrophilic coatings on the surface of multilevel 3D-printed (3DP) microfluidic devices via inkjet printing, thereby retaining the surface hydrophilicity for at least 6 months of storage. To the best of our knowledge, this is the first demonstration of capillary flow control in 3DP microfluidics enabled by inkjet printing. The method is used to create “stop” and “delay” valves to enable preprogrammed capillary flow for sequential release of fluids. To demonstrate further utilization in point-of-care sensing applications, screen printed organic electrochemical transistors are integrated within the microfluidic chips to sense, sequentially and independently from external actions, chloride anions in the (1–100) × 10−3 m range. The results present a cost-effective fabrication method of compact, yet comprehensive, all-printed sensing platforms that allow fast ion detection (<60 s), including the capability of automatic delivery of multiple test solutions. © 2023 The Authors., Correspondence Address: P. Andersson Ersman; RISE Research Institutes of Sweden, Digital Systems, Smart Hardware, Printed, Bio- and Organic Electronics, Norrköping, 60233, Sweden. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie grant agreement no. 813863 (BORGES).

Microfluidic surface chemistry can enable control of capillary-driven flow without the need for bulky external instrumentation. A novel pondered nonhomogeneous coating defines regions with different wetting properties on the microchannel walls. It changes the curvature of the liquid–air meniscus at various channel cross-sections and consequently leads to different capillary pressures, which is favorable in the strive toward automatic flow control. This is accomplished by the deposition of hydrophilic coatings on the surface of multilevel 3D-printed (3DP) microfluidic devices via inkjet printing, thereby retaining the surface hydrophilicity for at least 6 months of storage. To the best of our knowledge, this is the first demonstration of capillary flow control in 3DP microfluidics enabled by inkjet printing. The method is used to create “stop” and “delay” valves to enable preprogrammed capillary flow for sequential release of fluids. To demonstrate further utilization in point-of-care sensing applications, screen printed organic electrochemical transistors are integrated within the microfluidic chips to sense, sequentially and independently from external actions, chloride anions in the (1–100) × 10−3 m range. The results present a cost-effective fabrication method of compact, yet comprehensive, all-printed sensing platforms that allow fast ion detection (<60 s), including the capability of automatic delivery of multiple test solutions. © 2023 The Authors., Correspondence Address: P. Andersson Ersman; RISE Research Institutes of Sweden, Digital Systems, Smart Hardware, Printed, Bio- and Organic Electronics, Norrköping, 60233, Sweden. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie grant agreement no. 813863 (BORGES).

This report aims to study the degradation of poly(trimethylene carbonate) (PTMC) caused by the enzyme carboxylesterase in vitro. As well as to characterise polymer blends of f-BTI2g-TVTCN and poly(3-hydroxybutyric acid) as core components for organic electrochemical transistors (OETCs). This is to assess the suitability of these polymers in biodegradable biosensors. The degradation study of PTMC showed a lack of degradation in contrast to previous studies performed on the material; previous studies recorded a mass loss of between (5-8)% after two months. The cause for this discrepancy is still unknown but the evidence points to both systematic faults in the gravimetric analysis as well as random errors found in the equipment. The OECT showed that increasing the PHB fraction in the polymer blend resulted in a higher output. The most stable device consisted of a 1:6 blend of f-BTI2g-TVTCN to PHB. Fewer tests were conducted on the 1:10 blend because two devices were damaged during the experiment. The statistical impact of the smaller sample size cannot be overstated so further testing should be conducted to verify the results.

Neuromorphic systems that display synaptic conditioning based on biochemical signaling activity have recently been introduced in the form of artificial synapses that are model devices to develop tissue-interfaced platforms. In this regard, biohybrid synapses promise adaptive neuron-integrated functions. However, these systems suffer from both molecular cross-talk as biological neural circuits signal transmission typically involves more than one neuromodulator, and unstable electronics wirings as complex architectures are required to interface the tissues. Moreover, whilst novel spiking circuits can work as artificial neurons, they only recreate the biological electrical signaling pathway while electrochemical signal transduction is required for inter-neuron communication. As such, artificial chemically-mediated synapses are essential to perform memory/learning computing functions. Herein, an electrochemical neuromorphic organic device (ENODe) working as an artificial synapse that overcomes electrochemical and readout interferences while it emulates two neurotransmitters synaptic weight modulation and their recycling machinery at the synaptic cleft is shown. Neuronal short- and long-term plasticity are replicated by transducing two separate neurotransmitter-mediated chemical signals into reversible and nonreversible variations of PEDOT:PSS conductance. By exploiting the electrochromic properties of PEDOT:PSS, an alternative optical monitoring strategy is introduced which promises stable multidevice readout from complex bio-hybrid interfaces. The platform emulates high-order biological processes such as intrinsic forgetting, memory consolidation, and neurotransmitter co-modulation. These brain-inspired functionalities herald the development of tissue-integrated neuromorphic systems that combine spiking (electrical neurons) and nonspiking (electrochemical synapses) elements, thus envisioning prosthetic bridges for neural engineering and regenerative medicine.

Internal ion-gated organic electrochemical transistor (IGT) demonstrates volume-dependent transconductance with the unprecedented advantages of high speed and self-(de)doping capability among ion-based transistors. The novel characteristics have albeit rendered IGT a promising platform for integrated bioelectronics, its potential in high-frequency applications has yet been fully harnessed. Moreover, a study from a material's point of view is especially needed for this recently emerged platform as the necessity of maintaining the internal ion reservoir has posed difficulties in processing hydrated poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulphonate) (PEDOT:PSS) with electronically favorable morphologies. Herein, a comprehensive investigation of the structural and functional properties of ion-embedded PEDOT:PSS modified by different annealing temperatures is performed and correlated to the IGT performance. A short-time high-temperature annealing treatment is found effective in facilitating the formation of compact microstructures without significantly influencing film hydration. The structural improvement enhances the film's conductivity and hole mobility, with the corresponding IGTs exhibiting higher gain, higher conductance, and high cut-off frequency consistently in a batch. This study also successfully demonstrates the first use of electrochemical transistors like IGTs in high-frequency applications through proof-of-concept experiments simulating fluid estimation in 50 kHz bioimpedance analysis. This work contributes to the development of high-performance IGTs for extensive biological applications.

Organic electronic circuits based on organic electrochemical transistors (OECTs) are attracting great attention due to their printability, flexibility, and low voltage operation. Inverters are the building blocks of digital logic circuits (e.g., NAND gates) and analog circuits (e.g., amplifiers). However, utilizing OECTs in electronic logic circuits is challenging due to the resulting low voltage gain and low output voltage levels. Hence, inverters capable of operating at relatively low supply voltages, yet offering high voltage gain and larger output voltage windows than the respective input voltage window are desired. Herein, inverters realized from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate-based OECTs are designed and explored, resulting in logic inverters exhibiting high voltage gains, enlarged output voltage windows, and tunable switching points. The inverter designs are based on multiple screen-printed OECTs and a resistor ladder, where one OECT is the driving transistor while one or two additional OECTs are used as variable resistors in the resistor ladder. The inverters’ performances are investigated in terms of voltage gain, output voltage levels, and switching point. Inverters, operating at +/−2.5 V supply voltage and an input voltage window of 1 V, that can achieve an output voltage window with ∼110% increment and a voltage gain up to 42 are demonstrated. © 2022 The Authors., Funding details: Stiftelsen för Strategisk Forskning, SSF, SE13‐0045; Funding details: Knut och Alice Wallenbergs Stiftelse; Funding details: Horizon 2020, 825339, 964677; Funding details: Wallenberg Wood Science Center, WWSC; Funding text 1: This project has received funding from the Swedish foundation for Strategic Research (Silicon‐Organic Hybrid Autarkic Systems, Reference number: SE13‐0045), the Knut and Alice Wallenberg Foundation (Wallenberg Wood Science Center and Wallenberg Scholars), and the European Union's Horizon 2020 research and innovation programme under the grant agreement nos. 825339 (WEARPLEX) and 964677 (MITICS). M.B. gratefully acknowledges support from the Önnesjö Foundation.

Organic electronic circuits based on organic electrochemical transistors (OECTs) are attracting great attention due to their printability, flexibility, and low voltage operation. Inverters are the building blocks of digital logic circuits (e.g., NAND gates) and analog circuits (e.g., amplifiers). However, utilizing OECTs in electronic logic circuits is challenging due to the resulting low voltage gain and low output voltage levels. Hence, inverters capable of operating at relatively low supply voltages, yet offering high voltage gain and larger output voltage windows than the respective input voltage window are desired. Herein, inverters realized from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate-based OECTs are designed and explored, resulting in logic inverters exhibiting high voltage gains, enlarged output voltage windows, and tunable switching points. The inverter designs are based on multiple screen-printed OECTs and a resistor ladder, where one OECT is the driving transistor while one or two additional OECTs are used as variable resistors in the resistor ladder. The inverters’ performances are investigated in terms of voltage gain, output voltage levels, and switching point. Inverters, operating at +/−2.5 V supply voltage and an input voltage window of 1 V, that can achieve an output voltage window with ∼110% increment and a voltage gain up to 42 are demonstrated. © 2022 The Authors., Funding details: Stiftelsen för Strategisk Forskning, SSF, SE13‐0045; Funding details: Knut och Alice Wallenbergs Stiftelse; Funding details: Horizon 2020, 825339, 964677; Funding details: Wallenberg Wood Science Center, WWSC; Funding text 1: This project has received funding from the Swedish foundation for Strategic Research (Silicon‐Organic Hybrid Autarkic Systems, Reference number: SE13‐0045), the Knut and Alice Wallenberg Foundation (Wallenberg Wood Science Center and Wallenberg Scholars), and the European Union's Horizon 2020 research and innovation programme under the grant agreement nos. 825339 (WEARPLEX) and 964677 (MITICS). M.B. gratefully acknowledges support from the Önnesjö Foundation.

Organic electrochemical transistors (OECTs) have emerged as building blocks for low power circuits, biosensors, and neuromorphic computing. While p-type polymer materials for OECTs are well developed, the choice of high-performance n-type polymers is limited, despite being essential for cation and metabolite biosensors, and crucial for constructing complementary circuits. N-type conjugated polymers that have efficient ion-to-electron transduction are highly desired for electrochemical applications. In this contribution, three non-fused, planar naphthalenediimide (NDI)-dialkoxybithiazole (2Tz) copolymers, which systematically increase the amount of polar tri(ethylene glycol) (TEG) side chains: PNDI2OD-2Tz (0 TEG), PNDIODTEG-2Tz (1 TEG), PNDI2TEG-2Tz (2 TEG), are reported. It is demonstrated that the OECT performance increases with the number of TEG side chains resulting from the progressively higher hydrophilicity and larger electron affinities. Benefiting from the high electron mobility, excellent ion conduction capability, efficient ion-to-electron transduction, and low-lying lowest unoccupied molecular orbital energy level, the 2 TEG polymer achieves close to 105 on-off ratio, fast switching, 1000 stable operation cycles in aqueous electrolyte, and has a long shelf life. Moreover, the higher number TEG chain substituted polymer exhibits good conductance state retention over two orders of magnitudes in electrochemical resistive random-access memory devices, highlighting its potential for neuromorphic computing.

Organic electrochemical transistors formed by in operando electropolymerization of the semiconducting channel are increasingly becoming recognized as a simple and effective implementation of synapses in neuromorphic hardware. However, very few studies have reported the requirements that must be met to ensure that the polymer spreads along the substrate to form a functional conducting channel. The nature of the interface between the substrate and various monomer precursors of conducting polymers through molecular dynamics simulations is investigated, showing that monomer adsorption to the substrate produces an increase in the effective monomer concentration at the surface. By evaluating combinatorial couples of monomers baring various sidechains with differently functionalized substrates, it is shown that the interactions between the substrate and the monomer precursor control the lateral growth of a polymer film along an inert substrate. This effect has implications for fabricating synaptic systems on inexpensive, flexible substrates., Funding: Swedish Foundation for Strategic Research [RMX18-0083]; Swedish Research Council [2018-06197]; European Research Council [834677]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; Knut and Alice Wallenberg Foundation; Onnesjo Foundation

Organic electrochemical transistors formed by in operando electropolymerization of the semiconducting channel are increasingly becoming recognized as a simple and effective implementation of synapses in neuromorphic hardware. However, very few studies have reported the requirements that must be met to ensure that the polymer spreads along the substrate to form a functional conducting channel. The nature of the interface between the substrate and various monomer precursors of conducting polymers through molecular dynamics simulations is investigated, showing that monomer adsorption to the substrate produces an increase in the effective monomer concentration at the surface. By evaluating combinatorial couples of monomers baring various sidechains with differently functionalized substrates, it is shown that the interactions between the substrate and the monomer precursor control the lateral growth of a polymer film along an inert substrate. This effect has implications for fabricating synaptic systems on inexpensive, flexible substrates., Funding: Swedish Foundation for Strategic Research [RMX18-0083]; Swedish Research Council [2018-06197]; European Research Council [834677]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; Knut and Alice Wallenberg Foundation; Onnesjo Foundation

Research in smart textiles is growing due to the increased demand from the healthcare sector and people's urge to keep track of and analyze the signals and metrics from their bodies. Electrically conductive filaments are the most fundamental material for smart textiles. These filaments can be imbued with functionalities and useful in fields like energy storage, sensing, and actuation. To be able to meet the requirements that the latter applications require, fabrication techniques must be developed to provide better processability and sustainability in a cost-effective manner. Here, a mixture of a conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), and biobased cellulose nanofibrils (CNFs) was used to spin filaments utilizing a water-based process. These filaments show electrical conductivities up to 150 S/cm and tensile stiffness of 20 GPa. Interestingly, the PEDOT aligned to a similar degree as the CNFs during the spinning process without a drawing step, which is hypothesized to be caused by the attachment of PEDOT on the CNFs. Lastly, the filaments were tested in an organic electrochemical transistor (OECT) configuration, which resulted in a working device with an on/off ratio approaching 1500. Furthermore, the OECT exhibited stable behavior when changing temperature (20-80 °C) and relative humidity (40-80%). This aqueous spinning method, resulting in filaments with robust electronic properties in different temperature and humidity environments, show greats promise for future innovative smart textiles., QC 20230308

This work demonstrates a novel fabrication approach based on the combination of screen and aerosol jet printing to manufacture fully printed organic electrochemical transistors (OECTs) and OECT-based logic circuits on PET substrates with superior performances. The use of aerosol jet printing allows for a reduction of the channel width to ≈15 µm and the estimated volume by a factor of ≈40, compared to the fully screen printed OECTs. Hence, the OECT devices and OECT-based logic circuits fabricated with the proposed approach emerge with a high ON/OFF ratio (103–104) and remarkably fast switching response, reaching an ON/OFF ratio of >103 in 4–8 ms, which is further demonstrated by a propagation delay time of just above 1 ms in OECT-based logic inverter circuits operated at a frequency of 100 Hz. All-printed monolithically integrated OECT-based five-stage ring oscillator circuits further validated the concept with a resulting self-oscillation frequency of 60 Hz. © 2022 The Authors., Funding details: Horizon 2020, 813863, 825339; Funding text 1: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie grant agreement No 813863 (BORGES) and the European Union's Horizon 2020 research and innovation programme under the grant agreement No 825339 (WEARPLEX).

This work demonstrates a novel fabrication approach based on the combination of screen and aerosol jet printing to manufacture fully printed organic electrochemical transistors (OECTs) and OECT-based logic circuits on PET substrates with superior performances. The use of aerosol jet printing allows for a reduction of the channel width to ≈15 µm and the estimated volume by a factor of ≈40, compared to the fully screen printed OECTs. Hence, the OECT devices and OECT-based logic circuits fabricated with the proposed approach emerge with a high ON/OFF ratio (103–104) and remarkably fast switching response, reaching an ON/OFF ratio of >103 in 4–8 ms, which is further demonstrated by a propagation delay time of just above 1 ms in OECT-based logic inverter circuits operated at a frequency of 100 Hz. All-printed monolithically integrated OECT-based five-stage ring oscillator circuits further validated the concept with a resulting self-oscillation frequency of 60 Hz. © 2022 The Authors., Funding details: Horizon 2020, 813863, 825339; Funding text 1: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie grant agreement No 813863 (BORGES) and the European Union's Horizon 2020 research and innovation programme under the grant agreement No 825339 (WEARPLEX).

Organic electrochemical transistors formed by in operando electropolymerization of the semiconducting channel are increasingly becoming recognized as a simple and effective implementation of synapses in neuromorphic hardware. However, very few studies have reported the requirements that must be met to ensure that the polymer spreads along the substrate to form a functional conducting channel. The nature of the interface between the substrate and various monomer precursors of conducting polymers through molecular dynamics simulations is investigated, showing that monomer adsorption to the substrate produces an increase in the effective monomer concentration at the surface. By evaluating combinatorial couples of monomers baring various sidechains with differently functionalized substrates, it is shown that the interactions between the substrate and the monomer precursor control the lateral growth of a polymer film along an inert substrate. This effect has implications for fabricating synaptic systems on inexpensive, flexible substrates., Funding: Swedish Foundation for Strategic Research [RMX18-0083]; Swedish Research Council [2018-06197]; European Research Council [834677]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; Knut and Alice Wallenberg Foundation; Onnesjo Foundation

Organic electrochemical transistors formed by in operando electropolymerization of the semiconducting channel are increasingly becoming recognized as a simple and effective implementation of synapses in neuromorphic hardware. However, very few studies have reported the requirements that must be met to ensure that the polymer spreads along the substrate to form a functional conducting channel. The nature of the interface between the substrate and various monomer precursors of conducting polymers through molecular dynamics simulations is investigated, showing that monomer adsorption to the substrate produces an increase in the effective monomer concentration at the surface. By evaluating combinatorial couples of monomers baring various sidechains with differently functionalized substrates, it is shown that the interactions between the substrate and the monomer precursor control the lateral growth of a polymer film along an inert substrate. This effect has implications for fabricating synaptic systems on inexpensive, flexible substrates., Funding: Swedish Foundation for Strategic Research [RMX18-0083]; Swedish Research Council [2018-06197]; European Research Council [834677]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; Knut and Alice Wallenberg Foundation; Onnesjo Foundation

Organic electrochemical transistors formed by in operando electropolymerization of the semiconducting channel are increasingly becoming recognized as a simple and effective implementation of synapses in neuromorphic hardware. However, very few studies have reported the requirements that must be met to ensure that the polymer spreads along the substrate to form a functional conducting channel. The nature of the interface between the substrate and various monomer precursors of conducting polymers through molecular dynamics simulations is investigated, showing that monomer adsorption to the substrate produces an increase in the effective monomer concentration at the surface. By evaluating combinatorial couples of monomers baring various sidechains with differently functionalized substrates, it is shown that the interactions between the substrate and the monomer precursor control the lateral growth of a polymer film along an inert substrate. This effect has implications for fabricating synaptic systems on inexpensive, flexible substrates., Funding: Swedish Foundation for Strategic Research [RMX18-0083]; Swedish Research Council [2018-06197]; European Research Council [834677]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; Knut and Alice Wallenberg Foundation; Onnesjo Foundation

Organic electrochemical transistors (OECTs) have emerged as building blocks for low power circuits, biosensors, and neuromorphic computing. While p-type polymer materials for OECTs are well developed, the choice of high-performance n-type polymers is limited, despite being essential for cation and metabolite biosensors, and crucial for constructing complementary circuits. N-type conjugated polymers that have efficient ion-to-electron transduction are highly desired for electrochemical applications. In this contribution, three non-fused, planar naphthalenediimide (NDI)-dialkoxybithiazole (2Tz) copolymers, which systematically increase the amount of polar tri(ethylene glycol) (TEG) side chains: PNDI2OD-2Tz (0 TEG), PNDIODTEG-2Tz (1 TEG), PNDI2TEG-2Tz (2 TEG), are reported. It is demonstrated that the OECT performance increases with the number of TEG side chains resulting from the progressively higher hydrophilicity and larger electron affinities. Benefiting from the high electron mobility, excellent ion conduction capability, efficient ion-to-electron transduction, and low-lying lowest unoccupied molecular orbital energy level, the 2 TEG polymer achieves close to 105 on-off ratio, fast switching, 1000 stable operation cycles in aqueous electrolyte, and has a long shelf life. Moreover, the higher number TEG chain substituted polymer exhibits good conductance state retention over two orders of magnitudes in electrochemical resistive random-access memory devices, highlighting its potential for neuromorphic computing.

The increasing interest in organic electrochemical transistors (OECTs) for next-generation bioelectronic applications motivates the design of novel conjugated polymers with good electronic and ionic transport. Many conjugated polymers developed for organic field-effect transistors (OFETs) exhibit high charge carrier mobilities but they are not suitable for OECTs due to poor ion-uptake arising from the non polar alkyl chain substituted on the conjugated backbone. They are also sensitive to moisture, resulting in poor performance in aqueous electrolytes. Herein, the widely used conjugated building block diketopyrrolopyrrole (DPP) is used and functionalized it with polar triethylene glycol side chains (PTDPP-DT) to promote ion penetration. The electrical performance of PTDPP-DT based OECT in two types of aqueous electrolytes is studied and the electrochemical doping response is investivated. It is found that the tetrafluoroborate (BF4−) anion with large crystallographic radius allows high-efficiency electrochemical doping of the PTDPP-DT polymer, and thus gives rise to the high transconductance of 21.4 ± 4.8 mS with good device stability, where it maintained over 91 % of its doped-state drain current after over 500 cycles of pulse measurement.

Polar polythiophenes with oligoethylene glycol side chains are exceedingly soft materials. A low glass transition temperature and low degree of crystallinity prevents their use as a bulk material. The synthesis of a copolymer comprising 1) soft polythiophene blocks with tetraethylene glycol side chains, and 2) hard urethane segments is reported. The molecular design is contrary to that of other semiconductor-insulator copolymers, which typically combine a soft nonconjugated spacer with hard conjugated segments. Copolymerization of polar polythiophenes and urethane segments results in a ductile material that can be used as a free-standing solid. The copolymer displays a storage modulus of 25 MPa at room temperature, elongation at break of 95%, and a reduced degree of swelling due to hydrogen bonding. Both chemical doping and electrochemical oxidation reveal that the introduction of urethane segments does not unduly reduce the hole charge-carrier mobility and ability to take up charge. Further, stable operation is observed when the copolymer is used as the active layer of organic electrochemical transistors., QC 20210409

Organic electrochemical transistors (OECTs) are used in research and diagnostic applications due to their facile manufacture, scalability, and biocompatibility. In these devices, the source–drain current upon gate voltage application depends on ion concentration in the electrolyte. This study investigates whether an OECT can be employed to monitor bacterial growth since it is known that the concentration of charged species increases in bacterial cultures during growth. A poly(3,4-ethylenedioxythiophene):polystyrene sulfonate-based single-well OECT, compatible with long-term incubation of bacterial cultures, is fabricated. It is shown that the growth of Salmonella alters the transfer characteristics of the device and demonstrates how it can be applied to monitor growth in real-time by recording the source–drain current at gate voltage +0.5 V. The signal can also be measured in filtrates of bacterial cultures, devoid of bacterial cells. This suggests that the signal originates from charged metabolic products. Bacterial biofilm formation does not alter the device response. This proof-of-principle study presents OECT recordings as an alternative to optical methods, allowing bacterial growth to be monitored in transparent and opaque media alike. By measuring metabolic products rather than bacterial cell multiplication, insight into the stationary phase and other nondividing states may be obtained in the future., QC 20220824

Electrochemically induced volume changes in organic mixed ionic-electronic conductors (OMIECs) are particularly important for their use in dynamic microfiltration systems, biomedical machinery, and electronic devices. Although significant advances have been made to maximize the dimensional changes that can be accomplished by OMIECs, there is currently limited understanding of how changes in their molecular structures impact their underpinning fundamental processes and their performance in electronic devices. Herein, a series of ethylene glycol functionalized conjugated polymers is synthesized, and their electromechanical properties are evaluated through a combined approach of experimental measurements and molecular dynamics simulations. As demonstrated, alterations in the molecular structure of OMIECs impact numerous processes occurring during their electrochemical swelling, with sidechain length shortening decreasing the number of incorporated water molecules, reducing the generated void volumes and promoting the OMIECs to undergo different phase transitions. Ultimately, the impact of these combined molecular processes is assessed in organic electrochemical transistors, revealing that careful balancing of these phenomena is required to maximize device performance., Funding agencies: KAUSTKing Abdullah University of Science & Technology; Office of Sponsored Research (OSR) [OSR-2018-CRG/CCF-3079, OSR-2019-CRG8-4086, OSR-2018-CRG7-3749]; ERC Synergy Grant SC2 [610115]; European UnionEuropean Commission [952911, 862474]; EPSRCUK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC) [EP/T026219/1]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation; Wallenberg Wood Science Center [KAW 2018.0452]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; TomKat Center for Sustainable Energy at Stanford University

Organic electrochemical transistors (OECTs) have attracted great interest in the last few years as biochemical sensors due to their outstanding analytical performance, versatility, stability, and easiness of fabrication. While thin-film OECTs have been studied extensively, their manufacturing still presents some challenges. This report presents a simple approach for developing OECT using a paper substrate and a thick-film approach that shows outstanding performance. The channel is hand-made by dip pen deposition of the conducting polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS). This allows reproducible channel thickness in the order of 6 mu m, well above the conventionally used values. This device displays a high transconductance that exceeds 40 mS and an on-to-off current ratio of 3.8 x 10(3) comparable or superior to the state-of-the-art paper-based OECTs. The advantages of this approach are illustrated with the detection of H2O2 and glucose, obtaining sensitivities above 1.5 mA/dec. This simplified approach and high sensitivity may help to extend the use of the OECT-based sensors, particularly in the distributed and point-of need applications.

© 2020, © 2020 Taylor & Francis Group, LLC. The role of hydrogen peroxide in a wide range of biological processes has led to a steady increase in research into hydrogen peroxide determination in recent years, and conducting polymers have attracted much interest in electrochemistry as promising materials in this area. We present an overview of electrochemical devices for hydrogen peroxide determination using conducting polymers, either as a target or as a byproduct of redox reactions. We describe different combinations of electrode modifications through the incorporation of conducting polymers as the main component along with other materials or nanomaterials. We critically compare the analytical performances cited and highlight some of the future challenges for the feasible application of such devices.

[ES] El ácido ascórbico (AA), comúnmente conocido como vitamina C, es un importante agente antioxidante hidro-soluble y una vitamina esencial para el cuerpo humano. Sin embargo, nuestro cuerpo no es capaz de sintetizarla y ha de ser introducida mediante la comida en nuestra dieta diaria. Por ello, su desarrollo es objeto de interés por campos como la medicina o la industria alimentaria. Los métodos clásicos utilizados para la detección de AA (cromatográficos, enzimáticos, tritimétricos, técnicas electroanalíticas, etc.), conllevan la utilización de equipo y personal especializado, haciendo el proceso lento y dificultando así su uso diario. Por todo esto, el desarrollo de técnicas rápidas, simples y de bajo coste para su detección es de gran interés. Una alternativa con la que se cumplirían estos requisitos es el uso de sensores basados en transistores electroquímicos orgánicos (OECT por sus siglas en inglés, organic electrochemical transistors). Concretamente, la simplicidad y economía de estos semiconductores orgánicos con respecto a otros sensores electroquímicos, los hace una opción válida para la detección rápida y de bajo coste de sustancias químicas. El principal objetivo de este trabajo ha consistido en el desarrollo de un equipo electrónico de medida portátil del ácido ascórbico en alimentos, mediante el uso del microcontrolador 32-bits SAM3X8E de Atmel., [EN] Ascorbic Acid, commonly known as vitamin C, is an important water-soluble antioxidant agent and an essential vitamin for the human body. However, our body is not able to synthesize it, and it has to be introduced into our daily. Therefore, its development is the object of interest for fields such as medicine or food industry. Classical techniques used for the detection of AA (chromatography, enzymatic and titrimetric methods or electro-analytical techniques) involve the use of specialized equipment and personnel, making the process slow and difficult to use on a daily basis. Due to all of this, the development of fast, simple and low-cost techniques for detection is of great interest. An alternative that would meet these requirements is the use of sensors based on organic electrochemical transistors (OECT). Specially, the simplicity and economy of these organic semiconductors in comparison to other electrochemical sensors, makes them a valid option for fast and low-cost detection of chemicals. The main objective of this work has been to develop a portable and electronic device for measuring ascorbic acid in food, using Atmel’s SAM3X8E 32- bits microcontroller.

The organic electrochemical transistor (OECT) with a conjugated polymer as the active material is the elementary unit of organic bioelectronic devices. Improved functionalities, such as low power consumption, can be achieved by building complementary circuits featuring two or more OECTs. Complementary circuits commonly combine both p- and n-type transistors to reduce power draw. While p-type OECTs are readily available, n-type OECTs are less common mainly due to poor stability of the n-type active channel material in aqueous electrolyte. Here, a complementary circuit is made using a pair of OECTs having polyaniline (PANI) as the channel material in both transistors. PANI, with a finite electrochemical window accessible at voltages lower than 1 V, exhibits a peak in current versus gate voltage when used as an active channel in an OECT. The current peak has two slopes, one n-like and one p-like, which correspond to different electrochemical regimes of the same underlying conjugated polymer. The electrochemistry enables the design of a complementary circuit using only PANI as the channel material. The PANI-based circuit is shown to have excellent performance with gain of ≈7 and is transferred on a flexible biocompatible chitosan substrate with demonstrated operation in aqueous electrolyte., QCR 20201203AIP

[ES] El ácido ascórbico (AA), comúnmente conocido como vitamina C, es un importante agente antioxidante hidro-soluble y una vitamina esencial para el cuerpo humano. Sin embargo, nuestro cuerpo no es capaz de sintetizarla y ha de ser introducida mediante la comida en nuestra dieta diaria. Por ello, su desarrollo es objeto de interés por campos como la medicina o la industria alimentaria. Los métodos clásicos utilizados para la detección de AA (cromatográficos, enzimáticos, tritimétricos, técnicas electroanalíticas, etc.), conllevan la utilización de equipo y personal especializado, haciendo el proceso lento y dificultando así su uso diario. Por todo esto, el desarrollo de técnicas rápidas, simples y de bajo coste para su detección es de gran interés. Una alternativa con la que se cumplirían estos requisitos es el uso de sensores basados en transistores electroquímicos orgánicos (OECT por sus siglas en inglés, organic electrochemical transistors). Concretamente, la simplicidad y economía de estos semiconductores orgánicos con respecto a otros sensores electroquímicos, los hace una opción válida para la detección rápida y de bajo coste de sustancias químicas. El principal objetivo de este trabajo ha consistido en el desarrollo de un equipo electrónico de medida portátil del ácido ascórbico en alimentos, mediante el uso del microcontrolador 32-bits SAM3X8E de Atmel., [EN] Ascorbic Acid, commonly known as vitamin C, is an important water-soluble antioxidant agent and an essential vitamin for the human body. However, our body is not able to synthesize it, and it has to be introduced into our daily. Therefore, its development is the object of interest for fields such as medicine or food industry. Classical techniques used for the detection of AA (chromatography, enzymatic and titrimetric methods or electro-analytical techniques) involve the use of specialized equipment and personnel, making the process slow and difficult to use on a daily basis. Due to all of this, the development of fast, simple and low-cost techniques for detection is of great interest. An alternative that would meet these requirements is the use of sensors based on organic electrochemical transistors (OECT). Specially, the simplicity and economy of these organic semiconductors in comparison to other electrochemical sensors, makes them a valid option for fast and low-cost detection of chemicals. The main objective of this work has been to develop a portable and electronic device for measuring ascorbic acid in food, using Atmel’s SAM3X8E 32- bits microcontroller.

[ES] El ácido ascórbico (AA), comúnmente conocido como vitamina C, es un importante agente antioxidante hidro-soluble y una vitamina esencial para el cuerpo humano. Sin embargo, nuestro cuerpo no es capaz de sintetizarla y ha de ser introducida mediante la comida en nuestra dieta diaria. Por ello, su desarrollo es objeto de interés por campos como la medicina o la industria alimentaria. Los métodos clásicos utilizados para la detección de AA (cromatográficos, enzimáticos, tritimétricos, técnicas electroanalíticas, etc.), conllevan la utilización de equipo y personal especializado, haciendo el proceso lento y dificultando así su uso diario. Por todo esto, el desarrollo de técnicas rápidas, simples y de bajo coste para su detección es de gran interés. Una alternativa con la que se cumplirían estos requisitos es el uso de sensores basados en transistores electroquímicos orgánicos (OECT por sus siglas en inglés, organic electrochemical transistors). Concretamente, la simplicidad y economía de estos semiconductores orgánicos con respecto a otros sensores electroquímicos, los hace una opción válida para la detección rápida y de bajo coste de sustancias químicas. El principal objetivo de este trabajo ha consistido en el desarrollo de un equipo electrónico de medida portátil del ácido ascórbico en alimentos, mediante el uso del microcontrolador 32-bits SAM3X8E de Atmel., [EN] Ascorbic Acid, commonly known as vitamin C, is an important water-soluble antioxidant agent and an essential vitamin for the human body. However, our body is not able to synthesize it, and it has to be introduced into our daily. Therefore, its development is the object of interest for fields such as medicine or food industry. Classical techniques used for the detection of AA (chromatography, enzymatic and titrimetric methods or electro-analytical techniques) involve the use of specialized equipment and personnel, making the process slow and difficult to use on a daily basis. Due to all of this, the development of fast, simple and low-cost techniques for detection is of great interest. An alternative that would meet these requirements is the use of sensors based on organic electrochemical transistors (OECT). Specially, the simplicity and economy of these organic semiconductors in comparison to other electrochemical sensors, makes them a valid option for fast and low-cost detection of chemicals. The main objective of this work has been to develop a portable and electronic device for measuring ascorbic acid in food, using Atmel’s SAM3X8E 32- bits microcontroller.

[ES] El ácido ascórbico (AA), comúnmente conocido como vitamina C, es un importante agente antioxidante hidro-soluble y una vitamina esencial para el cuerpo humano. Sin embargo, nuestro cuerpo no es capaz de sintetizarla y ha de ser introducida mediante la comida en nuestra dieta diaria. Por ello, su desarrollo es objeto de interés por campos como la medicina o la industria alimentaria. Los métodos clásicos utilizados para la detección de AA (cromatográficos, enzimáticos, tritimétricos, técnicas electroanalíticas, etc.), conllevan la utilización de equipo y personal especializado, haciendo el proceso lento y dificultando así su uso diario. Por todo esto, el desarrollo de técnicas rápidas, simples y de bajo coste para su detección es de gran interés. Una alternativa con la que se cumplirían estos requisitos es el uso de sensores basados en transistores electroquímicos orgánicos (OECT por sus siglas en inglés, organic electrochemical transistors). Concretamente, la simplicidad y economía de estos semiconductores orgánicos con respecto a otros sensores electroquímicos, los hace una opción válida para la detección rápida y de bajo coste de sustancias químicas. El principal objetivo de este trabajo ha consistido en el desarrollo de un equipo electrónico de medida portátil del ácido ascórbico en alimentos, mediante el uso del microcontrolador 32-bits SAM3X8E de Atmel., [EN] Ascorbic Acid, commonly known as vitamin C, is an important water-soluble antioxidant agent and an essential vitamin for the human body. However, our body is not able to synthesize it, and it has to be introduced into our daily. Therefore, its development is the object of interest for fields such as medicine or food industry. Classical techniques used for the detection of AA (chromatography, enzymatic and titrimetric methods or electro-analytical techniques) involve the use of specialized equipment and personnel, making the process slow and difficult to use on a daily basis. Due to all of this, the development of fast, simple and low-cost techniques for detection is of great interest. An alternative that would meet these requirements is the use of sensors based on organic electrochemical transistors (OECT). Specially, the simplicity and economy of these organic semiconductors in comparison to other electrochemical sensors, makes them a valid option for fast and low-cost detection of chemicals. The main objective of this work has been to develop a portable and electronic device for measuring ascorbic acid in food, using Atmel’s SAM3X8E 32- bits microcontroller.

Triethylene glycol, a common side chain, is attached to two different dye moieties, diketopyrrolopyrrole (DPP) and isoindigo (II), and their bromo derivative monomers are copolymerized, respectively, with common bisstannyl alkylated bithiophene via Stille coupling. The resulting donor–acceptor low-bandgap copolymers, namely, PTDPP-DT and PTII-DT, are rationally deigned and synthesized conjugated polymeric systems suitable for doping. Both polymers are successfully investigated as single-component and composite-system-based electrochemical transistors and light-emitting electrochemical cells. A PTDPP-DT thin film exhibits relatively high electrical conductivity of up to 80 S cm−1 in the electrochemically doped state, whereas PTII-DT thin film prevents the macroscopic charge transport due to a large-scale crystalline disorientation. Upon evaluating both polymers as active conjugated materials in light-emitting electrochemical cells, they both exhibit emission under efficient electron/hole doping conditions.

A flexible, electrochromic, active matrix addressed display (AMAD) is demonstrated. The monolithically integrated AMAD, which contains a 3 × 3 array of organic electrochromic smart pixels (OESPs), is manufactured on a plastic substrate solely using screen printing. Each OESP is based on the combination of one organic electrochromic display (OECD) and one organic electrochemical transistor (OECT), where both devices are screen printed into multilayered vertical architectures. The conduction state of the OECT enables control of the color state of its corresponding OECD, thereby circumventing cross-talk effects in the resulting AMAD device. The manufacturing approach also involves electrical wires, which connect each OECD with its corresponding OECT and also serve as the addressing lines of the resulting AMAD device, that are formed by screen printing of an ink based on either silver or nanocopper., Funding details: European Commission, EC, FP7‐NMP‐2013‐SME‐7, 604568; Funding details: Stiftelsen för Strategisk Forskning, SSF, SE13‐0045; Funding text 1: This project was financially supported by the European Commission (FP7‐NMP‐2013‐SME‐7, project 604568 Printed Logic for Applications of Screen Matrix Activation Systems [PLASMAS]) and the Swedish Foundation for Strategic Research (Silicon‐Organic Hybrid Autarkic Systems, Reference number: SE13‐0045). The authors acknowledge Intrinsiq Materials for providing and sintering the nanocopper‐based screen printing ink.

A flexible, electrochromic, active matrix addressed display (AMAD) is demonstrated. The monolithically integrated AMAD, which contains a 3 × 3 array of organic electrochromic smart pixels (OESPs), is manufactured on a plastic substrate solely using screen printing. Each OESP is based on the combination of one organic electrochromic display (OECD) and one organic electrochemical transistor (OECT), where both devices are screen printed into multilayered vertical architectures. The conduction state of the OECT enables control of the color state of its corresponding OECD, thereby circumventing cross-talk effects in the resulting AMAD device. The manufacturing approach also involves electrical wires, which connect each OECD with its corresponding OECT and also serve as the addressing lines of the resulting AMAD device, that are formed by screen printing of an ink based on either silver or nanocopper., Funding details: European Commission, EC, FP7‐NMP‐2013‐SME‐7, 604568; Funding details: Stiftelsen för Strategisk Forskning, SSF, SE13‐0045; Funding text 1: This project was financially supported by the European Commission (FP7‐NMP‐2013‐SME‐7, project 604568 Printed Logic for Applications of Screen Matrix Activation Systems [PLASMAS]) and the Swedish Foundation for Strategic Research (Silicon‐Organic Hybrid Autarkic Systems, Reference number: SE13‐0045). The authors acknowledge Intrinsiq Materials for providing and sintering the nanocopper‐based screen printing ink.

Here, a multichannel organic electrochemical transistor (OECT) array is reported for electrophysiological monitoring and mapping of action potential propagation of a wide range of cardiac cells, including cell lines, primary cell lines, and human-sourced stem cell derivatives in 2D and 3D structures. The results suggest that the ability to exploit this OECT-based platform to map 2D action potential propagation provides a viable strategy to better characterize cardiac cells in response to various chronotropic drugs. The effects of chronotropic agents Isoproterenol and Verapamil on cardiac tissues validate the utility of OECT for drug screening capability, and a preliminary demonstration of a 64-channel OECT array to monitor the cardiac action potentials for better spatial resolution is presented. The study demonstrates that OECT will be a viable and versatile platform for applications in medical and pharmacological industries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim