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We report the convenient synthesis of a benzobis(imidazolium)-embedded conjugated polyelectrolyte pBBI by a Cu-catalyzed direct C‒H arylation of a cationic benzobis(imidazolium) monomer with a diiodide comonomer. pBBI shows weak fluorescence in solution due to rotation of the repeat units in the conjugated backbone, and enhanced fluorescence when electrostatically interacting with a variety of anions to form aggregates. Specially, pBBI responds to the bisulfite anion with intensified unique deep-blue fluorescence easily discriminated by naked eye.

We fabricated a TiO2-based micromotor that was asymmetrically decorated with a water-soluble conjugated polymer (WSP) on one hemisphere and glucose oxidase (GOx) on the opposite hemisphere. The WSP, which had photocatalytic activity for H2O2 decomposition, enabled motion of the micromotor under visible light. The GOx on the other hemisphere of the micromotor decomposed glucose to produce H2O2 and enabled motion of the micromotor without light irradiation. In addition, WSP and GOx were attached to TiO2 by chemical bonds, providing stability during use. As a result, the micromotor could move by self-generating H2O2 for its own fuel by consuming glucose even without photoirradiation. The micromotor could move faster than without visible light irradiation through the synergistic decomposition of glucose and H2O2 under visible light by the diffusiophoretic mechanism with a speed of 7.49 μm/s.

To detect neomycin, one of the common antibiotics in the environment and in food and which may pose harm to human health, a fluorescence sensing system based on an amphiphilic conjugated polyelectr...

The interface material is an indispensable part of perovskite solar cells (PSCs) because of its special functions. In this work, a conjugated polyelectrolyte, PTPADT-SO3Na, was synthesized and intr...

Conjugated polyelectrolyte/MWCNT/poly(pyrrole) (CPE-K/MWCNT/PPY) composites have been prepared by a simple solution mixing technique. Synthesis of PPY/CPE/MWCNT composites was characterized by scanning electron microscopy and thermogravimetric analysis. These nanocomposites of CPE-K/MWCNT/PPY were deposited onto a glassy carbon electrode (GCE) in order to fabricate a reliable Mg2+ cationic sensor. A plot called the calibration curve is produced from the current as a function of concentration of Mg2+ ion. This plot was found to be linear in the range 0.1 nM to 0.01 mM, which is defined as the linear dynamic range. According to the surface area of the GCE (0.0316 cm2) and the slope of the calibration curve, a high sensitivity (19.4968 µA µM–1 cm–2) of the Mg2+ ion sensor was calculated. A significant lower limit of detection (97.71 ± 4.89 pM) was obtained in association with a signal to noise ratio of 3. Sensor parameters such as reproducibility, long-time stability, and short response time were measured and found to be quite satisfactory. This new approach to Mg2+ detection with high sensitivity is suggested for application as a novel multifunctional sensing system. Besides, it was found to be very effective to analyze real environmental samples.

In the present study, we synthesized a new conjugated polyelectrolyte with the N-(α-isobutyryl)pyridinium bromide as substituents via the spontaneous, catalyst-free polymerization of 2-ethynylpyrid...

Colloidal semiconductor nanocrystals (NCs) and, recently, nanoplatelets (NPLs), owing to their efficient and narrow-band luminescence, are considered as frontier materials for light-emitting diode (LED) technology. NC-LEDs typically incorporate interfacial layers as charge regulators to ensure charge balancing and high performance. In this Letter, we show the prolongation of the lifetime of multilayer solution-processed NC-LEDs by combining a self-doped conductive conjugated polyelectrolyte and exfoliated molybdenum disulfide (MoS2) flakes as an alternative to PEDOT:PSS. The ink features a neutral pH and a tunable hydrophobicity that mainly results in a remarkable stability of LEDs, using CdSe/CdZnS NPLs.

Poly(3-alkylthiophene) (PT)-based conjugated polyelectrolytes (CPEs) constitute an important class of responsive polymers with excellent optical properties. The electrostatic interactions between PTs and target analytes trigger complexation and concomitant conformational changes of the PT backbones that produce distinct optical responses. These conformation-induced optical responses of the PTs enable them to be utilized as reporters for detection of various analytes by employing simple UV-vis spectrophotometry or the naked eye. Numerous PTs with unique pendant groups have been synthesized to tailor their interactions with analytes such as nucleotides, ions, surfactants, proteins, and bacterial and viral pathogens. In this perspective, we discuss PT-target analyte complexation for bioanalytical applications and highlight recent advancements in point-of-care and field deployable assays. Subsequently, we highlight a few areas of critical importance for future applications of PTs as reporters, including (i) design and synthesis of specific PTs to advance the understanding of the mechanisms of interaction with target analytes, (ii) using arrays of PTs and linear discriminant analysis for selective and specific detection of target analytes, (iii) translation of conventional homogeneous solution-based assays into heterogeneous membrane-based assay formats, and finally (iv) the potential of using PT as an alternative to conjugated polymer nanoparticles and dots in bioimaging. Ministry of Education (MOE) Nanyang Technological University This work was funded by the Singapore Ministry of Education Academic Research Fund Tier 2 (MOE2018-T2-1-025) and the NTU-NU Institute for NanoMedicine located at the International Institute for Nanotechnology, Northwestern University, USA and the Nanyang Technological University, Singapore; Agmt10/20/14.

Monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) are polycyclic aromatic hydrocarbon (PAH) metabolites that have been used widely as biomarkers for evaluating human PAH exposure. In this...

Electrostatic assembly of conjugated polyelectrolytes, which combine a π-conjugated polymer backbone with pendant ionic groups, offer an opportunity for tuning materials properties and a new route for formulating concentrated inks for printable electronics. Complex coacervation, a liquid-liquid phase separation upon complexation of oppositely charged polyelectrolytes in solution, is used to form dense suspensions of π-conjugated material. A model system of a cationic conjugated polyelectrolyte poly(3-[6'-{

Emulating essential synaptic working principles using a single electronic device has been an important research field in recent years. However, achieving sensitivity and energy consumption comparable to biological synapses in these electronic devices is still a difficult challenge. Here, we report the fabrication of conjugated polyelectrolyte (CPE)-based artificial synapse, which emulates important synaptic functions such as paired-pulse facilitation (PPF), spike-timing dependent plasticity (STDP) and spiking rate dependent plasticity (SRDP). The device exhibits superior sensitivity to external stimuli andlow-energy consumption. Ultrahigh sensitivity and low-energy consumption are key requirements for building up brain-inspired artificial systems and efficient electronic-biological interface. The excellent synaptic performance originated from (i) a hybrid working mechanism that ensured the realization of both short-term and long-term plasticity in the same device, and (ii) the mobile-ion rich CPE thin film that mediate migration of abundant ions analogous to a synaptic cleft. Development of this type of artificial synapse is both scientifically and technologically important for construction of ultrasensitive highly-energy efficient and soft neuromorphic electronics.

Electron injection layers (EILs) based on a simple polymer blend of polyethyleneimine ethoxylated (PEIE) and poly[(9,9-bis(3'-(( N, N-dimethyl)- N-ethylammonium)-propyl)-2,7-fluorene)- alt-2,7-(9,9-dioctylfluorene)] (PFN-Br) can suppress the dependence of organic light-emitting device (OLED) performance on thickness variation compared with single PEIE or PFN-Br EILs. PEIE and PFN-Br were compatible with each other and PFN-Br uniformly mixed in the PEIE matrix. PFN-Br in PEIE formed more fluorene-fluorene pairs than PFN-Br alone. In addition, PEIE:PFN-Br blends reduced the work function (WF) substantially compared with single PEIE or PFN-Br polymer. PEIE:PFN-Br blends were applied to EILs in fluorescent polymer-based OLEDs. Optimized PEIE:PFN-Br blend EIL-based devices presented lower driving voltages and smaller dependences of device performance on EIL thickness than single PEIE or PFN-Br-based devices. These improvements were attributed to electron-transporting fluorene moieties, increased fluorene-fluorene pairs working as channels of electron transport, and the large WF reduction effect of PEIE:PFN-Br blends.

The control of the optoelectronic properties of the interlayers of perovskite solar cells (PSCs) is crucial for achieving high photovoltaic performances. Of the solution-processable interlayer candidates, NiOx is considered one of the best inorganic hole-transporting layer (HTL) materials. However, the power conversion efficiencies (PCEs) of NiOx-based PSCs are limited by the unfavorable contact between perovskite layers and NiOx HTLs, the high density of surface trap sites, and the inefficient charge extraction from perovskite photoactive layers to anodes. Here, we introduce a new organic-inorganic double HTL consisting of a Cu:NiOx thin film passivated by a conjugated polyelectrolyte (PhNa-1T) film. This double HTL has a significantly lower pinhole density and forms better contact with perovskite films, which results in enhanced charge extraction. As a result, the PCEs of PSCs fabricated with the double HTL are impressively improved up to 17.0%, which is more than 25% higher than that of the corresponding PSC with a Cu:NiOx HTL. Moreover, PSCs with the double HTLs exhibit similar stabilities under ambient conditions to devices using inorganic Cu:NiOx. Therefore, this organic-inorganic double HTL is a promising interlayer material for high performance PSCs with high air stability.

Antibiotic-resistant bacterial infections have become a serious public health threat. In an effort to address this threat, we develop an imidazolium-functionalized conjugated polyelectrolyte that exhibits profound light-activated biocidal activity. Here we report the synthesis, photophysical properties, and biocidal activity of a regioregular head-to-tail polythiophene substituted with cationic imidazolium units (P3HT-Im) prepared by Grignard metathesis controlled polymerization. In water, P3HT-Im has a broad absorption in the visible region and exhibited a remarkably high biocidal efficiency with both Gram-positive and Gram-negative bacteria at sub-microgram per milliliter concentrations. Moreover, mammalian cell studies suggest that P3HT-Im is nontoxic to mammalian cells at concentrations of ≤20 μg/mL over a short time scale (≤1 h) in the dark and light, and the targeting rate-dependent selective mechanism is revealed. This study demonstrates the capability of P3HT-Im to achieve selective imaging and in...

Conjugated polyelectrolytes (CPEs) are promising hole transport materials for perovskite solar cells, whereas their severe intermolecular aggregation significantly affects the device performance. Here, long-chain alkyl imidazolium ionic liquid (IL) of 1-dodecyl-3-methylimidazolium bromide ([C12mim]Br) and conjugated polyelectrolytes of potassium poly[3-(4-carboxylatebutyl)thiophene (P3CT-K) are combined with different mass ratios. The UV–vis spectra and dynamic light scattering studies indicate that the aggregation behavior of P3CT-K is suppressed by IL, thus obtaining a smoother hole transport layer for the latter device fabrication, which efficiently improves the film quality of perovskite absorber and enhances the hole transport at the interface. As a consequence, the inverted PSCs based on P3CT-K/IL film as the HTL show considerable improvement in power conversion efficiency (PCE), from 16.21% to 18.81%, compared with pristine P3CT-K based device. These findings indicate that IL can effectively inhibit the aggregation of CPEs, providing a new pathway to further improve the performance of PSCs based on CPEs interlayer.

We measure the UV-visible absorption of an annealed hydrophobic conjugated polyelectrolyte as a function of the pH, for different temperatures and ionic strengths. The position of the absorption ma...

In the following report, a conjugated polyelectrolyte (CPE) blend has been introduced for the first time as a fluorescent probe of membrane organization. Insertion of the blend into the lipid doubl ...

A conjugated polyelectrolyte (CPE) named PBNBr, is prepared by post-quaternizing of poly{4,8-bis(octyloxy)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-9,9-bis(3′-((N,N-dimethylamino)propyl)fluorene-2,7-diyl} (PBN) with bromoethane. The chemical strucutes, electrooptical properties of the PBNBr is fully characterized. As compared with the PBN, the PBNBr exhibit much better methanol solution processibility, and more effectively tuning ability for the work function (Wf) of ITO (WF bare ITO, −4.8 eV, WF of ITO with PBN interlayer, −4.1 eV, WF of ITO with PBNBr interlayer −3.9 eV). The open circuit voltages (VOC) and power conversion efficiencies (PCEs) of polymer solar cells from the blend film of poly(3-hexylthiophene) (P3HT) and [6,6]-phenylC61-butyric acid methyl ester (PC61BM) with PBN and/or PBNBr modified ITO as cathode are respectively increased about 27% and 120% in contrast to those for the control devices with bare ITO as cathode. And PCEs of 4.21% and 4.53% are achieved in the PSCs with PBN ...

We crosslink an amino-functionalized polyfluorene by the solvent additive 1,8-diiodooctane (DIO). DIO remains in the film after drying of the main solvent and chemically binds to the amino-side groups after a low temperature annealing step, rendering the polyfluorene film insoluble in non-polar solvents. We correlate the amount of DIO, the reduction of operational voltage and increase in lifetime of solution-processed OLEDs. We demonstrate a fully solution-processed device using the crosslinked polyfluorene electron injection layer and an inkjet-printed Ag top electrode.

We introduce a facile method to form a well-deposited [6] , [6] -phenyl-C61-butyric acid methyl ester (PCBM) film on the surface of 2D perovskite by mixing the poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9–dioctylfluorene)] (PFN), which can benefit the film formation of PCBM as well as improve the electron extraction efficiency of electron transport layer (ETL). As a result, the optimized group presents an enhanced photovoltaic performance with power conversion efficiency of 12.7%, which is attributed to the improved interfacial contact and better matched energy alignment. It is observed that the fully covered and dense ETL (PCBM:PFN) leads to a better environmental stability of devices in ambient air condition without encapsulation.

In this work, we exploit the versatile function of cationic phosphonium-conjugated polythiophenes to develop multifunctional platforms for imaging and combined therapy (siRNA delivery and photodynamic therapy). The photophysical properties (absorption, emission and light-induced generation of singlet oxygen) of these cationic polythiophenes were found to be sensitive to molecular weight. Upon light irradiation, low molecular weight cationic polythiophenes were able to light-sensitize surrounding oxygen into reactive oxygen species (ROS) while the highest were not due to its aggregation in aqueous media. These polymers are also fluorescent, allowing one to visualize their intracellular location through confocal microscopy. The most promising polymers were then used as vectors for siRNA delivery. Due to their cationic and amphipathic features, these polymers were found to effectively self-assemble with siRNA targeting the luciferase gene and deliver it in MDA-MB-231 cancer cells expressing luciferase, leading to 30&ndash, 50% of the gene-silencing effect. In parallel, the photodynamic therapy (PDT) activity of these cationic polymers was restored after siRNA delivery, demonstrating their potential for combined PDT and gene therapy.

PCPDTBT-SO3 K (CPE-K), a conjugated polyelectrolyte, is presented as a mixed conductor material that can be used to fabricate high transconductance accumulation mode organic electrochemical transistors (OECTs). OECTs are utilized in a wide range of applications such as analyte detection, neural interfacing, impedance sensing, and neuromorphic computing. The use of interdigitated contacts to enable high transconductance in a relatively small device area in comparison to standard contacts is demonstrated. Such characteristics are highly desired in applications such as neural-activity sensing, where the device area must be minimized to reduce invasiveness. The physical and electrical properties of CPE-K are fully characterized to allow a direct comparison to other top performing OECT materials. CPE-K demonstrates an electrical performance that is among the best reported in the literature for OECT materials. In addition, CPE-K OECTs operate in the accumulation mode, which allows for much lower energy consumption in comparison to commonly used depletion mode devices.

Conjugated polyelectrolytes (CPEs) have been widely used as reporters in colorimetric assays targeting nucleic acids. CPEs provide naked eye detection possibility by their superior optical properties however, as concentration of target analytes decrease, trace amounts of nucleic acid typically yield colorimetric responses that are not readily perceivable by naked eye. Herein, we report a pixelated analysis approach for correlating colorimetric responses of CPE with nucleic acid concentrations down to 1 nM, in plasma samples, utilizing a smart phone with an algorithm that can perform analytical testing and data processing. The detection strategy employed relies on conformational transitions between single stranded nucleic acid-cationic CPE duplexes and double stranded nucleic acid-CPE triplexes that yield distinct colorimetric responses for enabling naked eye detection of nucleic acids. Cationic poly[N,N,N-triethyl-3-((4-methylthiophen-3-yl)oxy)propan-1-aminium bromide] is utilized as the CPE reporter deposited on a polyvinylidene fluoride (PVDF) membrane for nucleic acid assay. A smart phone application is developed to capture and digitize the colorimetric response of the individual pixels of the digital images of CPE on the PVDF membrane, followed by an analysis using the algorithm. The proposed pixelated approach enables precise quantification of nucleic acid assay concentrations, thereby eliminating the margin of error involved in conventional methodologies adopted for interpretation of colorimetric responses, for instance, RGB analysis. The obtained results illustrate that a ubiquitous smart phone could be utilized for point of care colorimetric nucleic acids assays in complex matrices without requiring sophisticated software or instrumentation., Graphical abstract Image 1, Highlights • A cost effective sensory cartridge and an algorithm compatible with smart phone are developed. • Conjugated polyelectrolyte impregnated paper for detection of nucleic acid. • A pixelated assay to visualize nucleic acid down to concentration of 1 nM.

A water-soluble anionic conjugated polyelectrolyte was successfully synthesized via the Suzuki cross-coupling reaction in the presence of a palladium catalyst. Using this fluorescent polyelectrolyte, a new concept for a rapid, label-free lysozyme-sensing method is proposed via possible naked-eye detection of the emission color change. Intermolecular exciton migration in the conjugated polyelectrolyte-based complex was adopted to enhance the selectivity and sensitivity for lysozyme sensing by the formation and dissocia- tion of the polymer-lysozyme assay complex in the absence and presence of the anti-lyso- zyme aptamer, respectively. The polymer-lysozyme complex showed red emission because of cooperative aggregation of the conjugated polyelectrolyte and lysozyme. Upon expo- sure to the aptamer, the complex dissociated into individual molecules, resulting in a trans- parent blue-emitting solution. This occurred because lysozyme is released from the complex by the aptamer via the more favorable binding between the two molecules (lyso- zyme and aptamer).

A new conjugated polyelectrolyte material, namely, poly [9,9-bis((6′- N , N , N -trimethylamino)hexyl)-fluorene- alt - co -benzoxadiazole dibromide] (PFBD) is reported as electron transport layer (ETL) in polymer solar cells. We observed a light-soaking effect and described how a pre-UV light treatment on PFBD ETL is essential for attaining higher efficiencies (>7%) and negate the light-soaking problem. The pre-UV light treatment on PFBD layer is found to directly influence its molecular structure and result in reduction of the work function and increased electron mobility in PFBD which corroborates well with the observed lower series resistances obtained from dark current analysis and impedance spectra, and therefore enhancement in open-circuit voltage and fill factor. Moreover, after the pre-UV light treatment, the maximal efficiency of the solar cells retains at a nearly similar level for at least 26 days.

When aqueous conjugated-polyelectrolyte colloidal solutions containing an adequate amount of surfactant with an appropriate hydrophile-lipophile balance were sprayed onto latent fingerprints (LFPs), the polymer nanoparticles were readily transferred to the LFPs to reveal highly distinguishable fluorescent images, while the LFPs themselves remained intact.

We present a general and straightforward one-step approach to enhance the photophysical properties of conjugated polyelectrolytes. Upon complexation with an amphiphilic polymer (polyvinylpyrrolidone), an anionic conjugated polyelectrolyte (poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene]) was prepared into small nanoparticles with exceptional photostability and brightness. The polymer fluorescence intensity was enhanced by 23 -fold and could be easily tuned by changing the order of addition. Single molecule experiments revealed a complete suppression of blinking. In addition, after only losing 18% of the original intensity, a remarkable amount of photons were emitted per particle (similar to 10(9), on average). This number is many folds greater than popular organic fluorescent dyes. We believe that an intimate contact between the two polymers is shielding the conjugated polyelectrolyte from the destructive photooxidation. The prepared nanohybrid particles will prove instrumental in single particle based fluorescent assays and can serve as a probe for the current state-of-the-art bioimaging fluorescence techniques.

The development of highly efficient latent fingerprint (LFP) technology remains extremely vital for forensic and criminal investigations. In this contribution, a straightforward, rapid, and cost-effective method has been established for the quick development of well-preserved latent fingerprint on multiple substrates, including plastic, glass, aluminum foil, metallic surfaces, and so forth, without any additional treatment, based on aggregation-induced enhanced emission-active conjugated polyelectrolyte (CPE) 3,3'-((2-(4-(1,2-diphenyl-2-(p-tolyl)vinyl)phenyl)-7-(7-methylbenzo[c][1,2,5]thiadiazol-4-yl)-9H-fluorene-9,9-diyl)bis(hexane-6,1-diyl))bis(1-methyl-1H-imidazol-3-ium) bromide, revealing clearly the third-level details (ridges, bifurcations, and pores) with high selectivity, high contrast, and no background interference even by blood stains, confirming the ability of the proposed technique for LFP detection with high resolution. The LFP development process was accomplished simply by immersing fingerprint-loaded substrate into the CPE solution for ∼1 min, followed by shaking off the residual polymer solution and then air drying. The CPE was readily transferred to the LFPs because of the strong electrostatic and hydrophobic interaction between the CPE molecules and the fingerprint components revealing distinct fluorescent images on various smooth nonporous surfaces.

The iminodiacetate-Ni2+-hexahistidine system is extensively used in protein purification. In this study, an anionic conjugated polyelectrolyte (CPE) with a poly(p-phenylene ethynylene) backbone and iminodiacetate side chains, named PPEIDA, was designed and synthesized. Recognition and visualization of hexahistidine-tagged (His-tagged) proteins using PPEIDA was demonstrated.

A PTB7-based cationic narrow band-gap polyelectrolyte, named PTB7-NBr, has been designed and synthesized as a cathode interfacial material for polymer solar cells. PTB7-NBr exhibits excellent cathode interfacial modification in solar cells with PTB7 and PTB7-Th as donor polymer and a high PCE of 9.24% was achieved.

The intrinsic acidic nature of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole-transporting layer (HTL) induces interfacial protonation and limits the device performance in organic solar cells based on basic pyridylthiadiazole units. By utilizing a pH neutral, water/alcohol soluble conjugated polyelectrolyte CPE-K as the HTL in p-DTS(PTTh2)2:PC71BM solar cells, a 60% enhancement in PCE has been obtained with an increased V(bi), reduced R(s), and improved charge extraction. These effects originate from the elimination of interfacial protonation and energy barrier compared with the PEDOT:PSS HTL.

We designed and synthesized a novel conjugated polyelectrolyte (CPE), poly{3-[2-[4,8-bis(2-ethyl-hexyloxy)-6-methyl-1,5-dithia-s-indacen-2-yl]-9-(3-dimethylamino-propyl)-7-methyl-9H-fluoren-9-yl]-propyl}-dimethyl-amine (PBN). We employed PBN as an electron-transporting layer on a ZnO layer and constructed a highly efficient, inverted structure device consisting of a mixture of poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PTB7) and PC70BM, achieving a high power conversion of up to 8.6%, constituting a 21.1% improvement over the control device performance (7.1%) prepared without a PBN layer. This result was ascribed to the reduced interfacial resistance and the improved charge transport and collection through the PBN electron transport layer.

This study demonstrates the incorporation of a Cs 2 CO 3 :conjugated polyelectrolyte blended interfacial layer between the emissive layer and a silver (Ag) cathode, for realizing all-solution processed polymer light-emitting diodes. For a device with poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) as the emissive layer, this approach improves the maximum luminance of approximately 80,000 cd/m 2 and maximum current efficiency of 10.6 cd/A. It is clarified that the interfacial layer prevents Ag nanoparticles from penetrating into the emissive layer, resulting in yellow–green emission from F8BT. We also demonstrate the possibility of all-solution processed polymer light-emitting diodes utilizing solution-processed Cs 2 CO 3 :conjugated polyelectrolyte interfacial layer and Ag nano-ink.

A conjugated polyelectrolyte (CPE) based on a poly(phenylene ethynylene) backbone designed to avoid interchain aggregation was adsorbed onto n-type zinc oxide (0001) single crystals. Photophysical, atomic force microscopy, and photoelectrochemical measurements confirm the absence of aggregation in solution and on ZnO single-crystal surfaces. At high surface coverage on the ZnO surface, individual polymer chains are resolved, and photocurrent efficiency measurements suggest that charge injection occurs with modest efficiency.

A new “off-on” switch for sensitive and selective fluorescence detection of biothiols[glutathione(GSH), cysteine(Cys) and homocysteine(Hcy)] was developed based on an anionic conjugated polyelectrolyte(CPE), pyridyl-functionalized poly(phenylene ethynylene)(P1). The fluorescence of P1 can be significantly quenched by Ag+ due to complexation-mediated interpolymer aggregation. Furthermore, biothiols can efficiently recover the fluorescence intensity of P1 as a result of the stronger binding between thiol group and Ag+, which dissociates P1 from the P1/Ag+ complex and disrupts interpolymer aggregation. Under optimum conditions, a good linear relationship in a range of 100–4200 nmol/L is obtained for GSH with a detection limit of 80 nmol/L(S/N=3). As a result of specific interaction between the thiol group and Ag+, the proposed method shows a high selectivity for biothiols. In addition, the CPE-based fluorescence “off-on” switch has been used to quantitatively detect total biothiols in cell lysates.

This Feature Article focuses on recent progress made in elucidating the intermolecular interactions between a novel class of synthetic phenylene ethynylene (PPE)-based conjugated polyelectrolyte polymers (CPEs) and oligomers (OPEs) and multiscale cellular targets that give rise to their remarkable broad spectrum biocidal activity. We first review the interactions and self-assembly behaviors of the CPEs and OPEs with a set of vital biomolecules, including lipids, proteins, and nucleic acids, that reveal the potential pathways by which synthetic biocidal agents could exert toxicity. An overview of the antimicrobial effects and mechanisms of the CPEs and OPEs on multiple clinically relevant pathogens is then presented, with an emphasis on the morphological damage induced by the biocidal compounds toward the pathogens. Finally, we discuss the cytotoxicity of these materials against mammalian cells and human tissues to explore the potential applications of the CPEs and OPEs as antiseptics. We also pose some unanswered questions about their antimicrobial mechanisms, which provide direction for a future study.