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Introduction: LIG is a biopolymer found in vascular plant cell walls that is created by networks of hydroxylated and methoxylated phenylpropane that are randomly crosslinked. Plant cell walls contain LIG, a biopolymer with significant potential for usage in modern industrial and pharmaceutical applications. It is a renewable raw resource. The plant is mechanically protected by this substance, which may increase its durability. Because it has antibacterial and antioxidant qualities, LIG also shields plants from biological and chemical challenges from the outside world. Researchers have done a great deal of work to create new materials and substances based on LIG. Numerous applications, including those involving antibacterial agents, antioxidant additives, UV protection agents, hydrogel-forming molecules, nanoparticles, and solid dosage forms, have been made with this biopolymer. Methods: For this review, a consistent literature screening using the Pubmed database from 2019–2024 has been performed. Results: The results showed that there is an increase in interest in lignin as an adaptable biomolecule. The most recent studies are focused on the biosynthesis and antimicrobial properties of lignin-derived molecules. Also, the use of lignin in conjunction with nanostructures is actively explored. Conclusions: Overall, lignin is a versatile molecule with multiple uses in industry and medical science [ABSTRACT FROM AUTHOR]

The advancement in performance in the domain of flexible wearable strain sensors has become increasingly significant due to extensive research on laser-induced graphene (LIG). An innovative doping modification technique is required owing to the limited progress achieved by adjusting the laser parameters to enhance the LIG's performance. By pre-treating with AgNO3, we successfully manufactured LIG with a uniform dispersion of silver nanoparticles across its surface. The experimental results for the flexible strain sensor exhibit exceptional characteristics, including low resistance (183.4 Ω), high sensitivity (426.8), a response time of approximately 150 ms, and a relaxation time of about 200 ms. Moreover, this sensor demonstrates excellent stability under various tensile strains and remarkable repeatability during cyclic tests lasting up to 8000 s. Additionally, this technique yields favorable results in finger bending and hand back stretching experiments, holding significant reference value for preserving the inherent characteristics of LIG preparation in a single-step and in situ manner. [ABSTRACT FROM AUTHOR]

Ice accumulation poses considerable challenges in transportation, notably in the domain of general aviation. The present study combines the strengths and limitations of conventional aircraft deicing techniques with the emerging trend toward all-electric aircraft. This study aims to utilize laser-induced graphene (LIG) technology to create a multifunctional surface, seamlessly integrating hydrophobic properties with efficient electrical heating to mitigate surface icing effectively. We investigated the utilization of a 10.6 μm CO2 laser for direct writing on polyimide (PI), a widely used insulating encapsulation material. From the thermomechanical perspective, our initial analysis using COMSOL Multiphysics software (V5.6) revealed that when the laser power P exceeds 5 W, the PI substrate experiences ablative damage. The experimental results show that when P ≤ 5 W, an increase in power has a positive impact on the quality, surface porosity, roughness reduction, line-spacing reduction, and water contact-angle enhancement of the graphene. Conversely, when P > 5 W, higher power negatively affects both the substrate and the graphene structure by inducing excessive ablation. However, it influences the graphene line height positively and is consistent with overall experimental–simulation congruence. Furthermore, the incorporation of high-quality graphene resulted in a surface that exhibited higher contact angles (CA > 120°), lower energy consumption, and higher heating efficiency compared to the use of traditional electrically heated materials for anti-icing applications. The potential applications of this one-step fabrication method extend across various industries, particularly aviation, marine engineering, and other ice-prone domains. Moreover, the method has extensive prospects for addressing pivotal challenges associated with ice formation and serves as an innovative and efficient anti-icing technology. [ABSTRACT FROM AUTHOR]

In recent years, wearable flexible sensors have garnered significant attention for their potential in monitoring human physiological signals. Current research focuses on flexible sensors with a wide linear range, high sensitivity, and excellent reliability. Micronanostructures have been introduced to balance these three features to some extent. Inspired by the micronanostructures of human fingerprints, we propose a fingerprint-like flexible sensor that combines polydimethylsiloxane with a grating structure and laser-induced graphene. This fingerprint-like flexible sensor exhibits several desirable characteristics: a wider linear range (0-180°), faster response time (0.3 s), higher sensitivity (688.5 kPa-1), and excellent reliability (>10,000 cycles). These features make fingerprint-like flexible sensors particularly suitable for detecting various human physiological signals, including finger flexion, elbow flexion, finger pressure, and pulse. Therefore, there is considerable potential for integrating multiple fingerprint-like sensors into human physiological signal monitoring applications. This approach offers a promising direction for the future development of wearable flexible sensors. [ABSTRACT FROM AUTHOR]

Laser-inscribed graphene (LIG) is an emerging material for micro-electronic applications and is being used to develop supercapacitors, soft actuators, triboelectric generators, and sensors. The fabrication technique is simple, yet the batch-to-batch variation of LIG quality is not well documented in the literature. In this study, we conduct experiments to characterize batch-to-batch variation in the manufacturing of LIG electrodes for applications in electrochemical sensing. Numerous batches of 36 LIG electrodes were synthesized using a CO2 laser system on polyimide film. The LIG material was characterized using goniometry, stereomicroscopy, open circuit potentiometry, and cyclic voltammetry. Hydrophobicity and electrochemical screening (cyclic voltammetry) indicate that LIG electrode batch-to-batch variation is less than 5% when using a commercial reference and counter electrode. Metallization of LIG led to a significant increase in peak current and specific capacitance (area between anodic/cathodic curve). However, batch-to-batch variation increased to approximately 30%. Two different platinum electrodeposition techniques were studied, including galvanostatic and frequency-modulated electrodeposition. The study shows that formation of metallized LIG electrodes with high specific capacitance and peak current may come at the expense of high batch variability. This design tradeoff has not been discussed in the literature and is an important consideration if scaling sensor designs for mass use is desired. This study provides important insight into the variation of LIG material properties for scalable development of LIG sensors. Additional studies are needed to understand the underlying mechanism(s) of this variability so that strategies to improve the repeatability may be developed for improving quality control. The dataset from this study is available via an open access repository. [ABSTRACT FROM AUTHOR]

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The present work is aimed at studying how spatially periodic modulations of the refractive index of the medium, i.e., laser-induced gratings (LIGs), generated in a gas mixture containing methane (CH4) by nanosecond pulses of resonant mid-infrared laser radiation, can be used to measure various gas parameters. It is investigated to what extent the temporal profiles of the LIG signals, recorded as the power of the diffracted by LIGs continuous wave probe radiation, are specific to the composition, pressure, and temperature of a selected buffer gas. This specificity is illustrated by the LIG signal profiles recorded in the experiments in different gas mixtures under various conditions. Experimental data show that large LIG signals can be obtained even in mixtures with CH4 concentrations as low as ∼100 parts per million due to the strong absorption of the excitation light and subsequent rapid, highly exothermic, and partner-dependent collisional energy exchange of the laser-excited molecules with the environment. These two factors ensure high LIG generation efficiency by a small number of CH4 molecules and high sensitivity of signal strength and profile to variations of gas parameters. [ABSTRACT FROM AUTHOR]

The development of graphene-based electrodes for application in energy storage and energy harvesting devices represents an important strategy for producing wearable devices with requisites of flexibility and good electrochemical performance. Herein, the use of laser-induced graphene (LIG) has been explored as a simple and efficient method for the production of interdigitated microsupercapacitors (μSCs) and back electrodes for triboelectric nanogenerators (TENGs) active layers by direct production of graphene from Kapton polyimide and by the transference of the pattern to polydimethylsiloxane (a typical tribonegative layer for TENG). An open circuit voltage of 189.7 V, short circuit current of 39.8 μA, and power of 302.5 μW (power density of 20.2 μW/cm2) was observed for the conventional TENG while an areal capacitance of 2.5 mF/cm2 with good retention in the energy generation and cyclability in energy storage was observed for the microsupercapacitor. The most relevant aspect to be considered is a single-step method for transference of back-electrode to the Poly(dimethylsiloxane) requiring minimal processing steps for morphology control in the friction layer and self-powered behavior for integration of TENG/microsupercapacitor in a power unit cell.

Introduction: LIG is a biopolymer found in vascular plant cell walls that is created by networks of hydroxylated and methoxylated phenylpropane that are randomly crosslinked. Plant cell walls contain LIG, a biopolymer with significant potential for usage in modern industrial and pharmaceutical applications. It is a renewable raw resource. The plant is mechanically protected by this substance, which may increase its durability. Because it has antibacterial and antioxidant qualities, LIG also shields plants from biological and chemical challenges from the outside world. Researchers have done a great deal of work to create new materials and substances based on LIG. Numerous applications, including those involving antibacterial agents, antioxidant additives, UV protection agents, hydrogel-forming molecules, nanoparticles, and solid dosage forms, have been made with this biopolymer. Methods: For this review, a consistent literature screening using the Pubmed database from 2019–2024 has been performed. Results: The results showed that there is an increase in interest in lignin as an adaptable biomolecule. The most recent studies are focused on the biosynthesis and antimicrobial properties of lignin-derived molecules. Also, the use of lignin in conjunction with nanostructures is actively explored. Conclusions: Overall, lignin is a versatile molecule with multiple uses in industry and medical science

Air, a widely recognized dielectric material, is employed as a dielectric layer in this study. We present a triboelectric sensor with a laser-induced graphene (LIG) electrode and an air-trapped pad using silicone rubber (SR). A very thin device with a thickness of 1 mm and an effective gap for contact–separation between the films of silicone rubber and polyimide (PI) of 0.6 mm makes the device extremely highly sensitive for very low amplitudes of pressure. The fabrication of LIG as an electrode material on the surface of PI is the key reason for the fabrication of the thin sensor. In this study, we showed that the fabricated air-trapped padded sensor (ATPS) has the capability to generate an output voltage of ~32 V, a short-circuit current of 1.2 µA, and attain a maximum power density of 139.8 mW m−2. The performance of the ATPS was compared with a replicated device having a hole on the pad, allowing air to pass through during contact–separation. The observed degradation in the electrical output suggests that the trapped air in the pad plays a crucial role in enhancing the output voltage. Therefore, the ATPS emerges as an ultra-sensitive sensor for healthcare sensing applications. [ABSTRACT FROM AUTHOR]

The advancement in performance in the domain of flexible wearable strain sensors has become increasingly significant due to extensive research on laser-induced graphene (LIG). An innovative doping modification technique is required owing to the limited progress achieved by adjusting the laser parameters to enhance the LIG’s performance. By pre-treating with AgNO3, we successfully manufactured LIG with a uniform dispersion of silver nanoparticles across its surface. The experimental results for the flexible strain sensor exhibit exceptional characteristics, including low resistance (183.4 Ω), high sensitivity (426.8), a response time of approximately 150 ms, and a relaxation time of about 200 ms. Moreover, this sensor demonstrates excellent stability under various tensile strains and remarkable repeatability during cyclic tests lasting up to 8000 s. Additionally, this technique yields favorable results in finger bending and hand back stretching experiments, holding significant reference value for preserving the inherent characteristics of LIG preparation in a single-step and in situ manner.

Laser-inscribed graphene (LIG) is an emerging material for micro-electronic applications and is being used to develop supercapacitors, soft actuators, triboelectric generators, and sensors. The fabrication technique is simple, yet the batch-to-batch variation of LIG quality is not well documented in the literature. In this study, we conduct experiments to characterize batch-to-batch variation in the manufacturing of LIG electrodes for applications in electrochemical sensing. Numerous batches of 36 LIG electrodes were synthesized using a CO2 laser system on polyimide film. The LIG material was characterized using goniometry, stereomicroscopy, open circuit potentiometry, and cyclic voltammetry. Hydrophobicity and electrochemical screening (cyclic voltammetry) indicate that LIG electrode batch-to-batch variation is less than 5% when using a commercial reference and counter electrode. Metallization of LIG led to a significant increase in peak current and specific capacitance (area between anodic/cathodic curve). However, batch-to-batch variation increased to approximately 30%. Two different platinum electrodeposition techniques were studied, including galvanostatic and frequency-modulated electrodeposition. The study shows that formation of metallized LIG electrodes with high specific capacitance and peak current may come at the expense of high batch variability. This design tradeoff has not been discussed in the literature and is an important consideration if scaling sensor designs for mass use is desired. This study provides important insight into the variation of LIG material properties for scalable development of LIG sensors. Additional studies are needed to understand the underlying mechanism(s) of this variability so that strategies to improve the repeatability may be developed for improving quality control. The dataset from this study is available via an open access repository.

• A simple and scalable method is developed for detecting trimethoprim (TMP). • A novel integration of [SeO 3 ]2− in La(OH) 3 lattice is proposed for TMP oxidation. • A porous filter is formed in situ on the µTMP-chip to avoid sample processing. • The chip detects TMP in real soil samples (recovery of 94.3–97.6 %). • Without the in-situ filter trapping biomass, the efficiency decreases by 15–45 %. The improper disposal of antibiotics in water bodies and using contaminated wastewater in irrigation severely damage the environment. Despite efforts to monitor these contaminants, effective detection methods are limited. Here, we design and develop a novel microfluidic electrochemical (EC) sensor for on-site detection of trimethoprim (TMP) using a selenite-enriched lanthanum hydroxide (La(OH) 3 :SeO x) working electrode and a polyimide (PI)-filter integrated microfluidic channel (MFC), thus termed a "µTMP-chip". For the first time, we introduced a new two-pronged strategy for enhancing TMP detection: i) incorporating selenite into the La(OH) 3 lattice to improve charge transfer properties and ii) using a laser-processed PI filter in the MFC to trap and isolate complex biomasses. Material characterizations confirmed that incorporating selenite into the La(OH) 3 lattice initiated La–O–Se bond formation and enhanced hybridization between the La 4f and O 2p orbitals. This process created holes in the O 2p valence band and improved the charge transfer properties, thus enhancing both sensitivity and selectivity. EC studies confirmed that when the PI filter is not used in the MFC, the µTMP-chip experiences a 15–45 % drop in efficiency. The scalable µTMP-chip offers cost-effective, highly reproducible TMP detection in soil and water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption-controlled electrochemical system of TMB on PtNP-modified LIG surface. • TMB electrochemical reaction with reversible dimerization: voltammetric response. • TMB electrochemical reaction coupled to preceding oxidation: impedimetric response. • Adsorption-associated phasance as a function of affinity-bound protein concentration. • Capacitive immunosensing of rheumatoid factor; LOD = 0.515 U mL−1 in spiked serum. Electrokinetic modelling and experimental studies are conducted on an adsorption system, with a model redox-active adsorbate 3,3′,5,5′-tetramethylbenzidine (TMB), strongly adsorbed to a platinum nanoparticle (PtNP)-modified porous laser induced graphene (LIG) surface. The adsorption-assisted system defined here involves an electrochemical reaction coupled to a preceding, surface-bound, chemical oxidation of the adsorbate. TMB is also known to undergo intermediate reversible dimerization during oxidation. A shift in the general expressions governing the voltammetric trends due to this reversible dimerization step, and the associated impact on the electrokinetic parameters is presented here for the first time. Impedance analysis reveals a modified Randles circuit, with the faradaic contribution of the adsorbate represented by a CPE circuit component. The adsorption-associated phasance, Q ads , is expressed as a function of the surface concentrations, Γ O and Γ R , of the oxidised and reduced forms. Changes in the total surface concentration of the adsorbate, Γ m , as a result of the presence of localised non-conductive entities, such as proteins, can be correlated to Q ads , and subsequently, this capacitive change can be utilised for affinity sensing of an antigen on a specific immunosurface. Proof of concept is carried out with the immunosensing of a model protein, rheumatoid factor, on a PtNP-modified LIG surface biofunctionalised with the specific capture probe, the Fc fragment of IgG. The relationship between the antigenic concentration C RF , Q ads and Γ m is established. This label-free, adsorption-assisted, capacitive biosensing mechanism has not be reported previously, to the best of our knowledge, with a linear range of 0–300 U mL−1 and an LOD of 0.515 U mL−1 in spiked serum samples, comparable to the gold standard, ELISA. [ABSTRACT FROM AUTHOR]