Polypyrrole Nanowires Research Articles

A Simple Route to Fabricate Ultralong and Uniform Polypyrrole Nanowires with High Electrochemical Capacitance for Supercapacitor Electrodes

This work demonstrated a straightforward strategy to fabricate ultralong interconnected polypyrrole (PPy-GS) nanowires with a gemini surfactant (GS) as a soft template and dopant. Pure PPy particles and a PPy nanowire doped with CTAB (PPy-CTAB) were prepared for comparison. The results showed that the electrochemical performances, conductivity, and morphology of PPy-GS could be significantly changed by changing the concentration of GS in the aqueous phase owing to the different self-assembly behaviors. When the molar ratio of pyrrole, APS, and GS was 1:1:0.4, an interconnected ultralong and uniform PPy-GS nanowire with the largest surface area, the smallest average pore size, the lowest contact angle, and the highest conductivity can be obtained, resulting in the formation of effective electrolyte transport channels and faster electron transport pathways. Compared with pure PPy particles and the PPy-CTAB nanowire, the incorporation of GS significantly enhanced the conductivity and specific capacitance of PPy-GS-40%. The conductivity of PPy-GS-40% was up to 13.54 S/cm compared with 1.17 S/cm for PPy particles and 3.84 S/cm for the PPy-CTAB nanowire. Also, the highest specific capacitance of PPy-GS reached up to 556 F/g at 1 A/g compared with 233 F/g for PPy particles and 397 F/g for the PPy-CTAB nanowire. A total of 85.4% of the initial capacitance was retained even after 2000 cycles at 1.0 A/g. The energy density and power density of the PPy-GS-40% symmetrical supercapacitor were 49.4 Wh/kg and 400 W/kg, respectively. The good electrochemical properties of the PPy-GS electrode suggest a tremendous potential in the high-performance electrode not only for supercapacitors but extensively for various energy storage applications.

WS2@PPy heterostructured high performance supercapacitor self-powered by PVDF piezoelectric separator

Self-charging supercapacitors have elicited immense concern for grid-scale power supply applications. Designing energy harvesting and storage systems as an integrated device has therefore become an imperative research interest. Herein, for the very first time, WS2 nanospheres adorned with polypyrrole (PPy) nanowires have been explored for supercapacitor application. The electroactive WS2@PPy heterostructure exhibited a specific capacitance of 245 F/g at a current density of 1 A/g and high cyclic stability of 99.2 % up to 10,000 cycles. Self-powered symmetric supercapacitor device (SPSSC) was assembled employing WS2@PPy heterostructure as electrode material and a PVDF film separator as a piezo-generator. The self-charging piezoelectric phenomenon of SPSSC device was tested by finger pressing, which offered a maximum output potential of 880 mV in 60 s and the device exhibited a specific capacitance of 337.7 F/g, energy density of 26.38 Wh/kg and power density of 1874 W/kg within a wide voltage window of 1.5 V. This work can open up avenues in employing WS2 based electrode materials for new era self-powered supercapacitor applications.

Cobalt sulfide nanosheets decorated on polypyrrole nanowires for improved charge storage in supercapacitors

Nanostructured cobalt sulfide-based electrode materials for supercapacitors (SCs) still suffer from easy aggregation, sluggish reaction kinetics, and poor structural stability. To resolve these issues, we adopt a two-step electrochemical deposition method to fabricate CoS nanosheets decorated on polypyrrole (PPy) nanowires that grow directly on Ni foam. The PPy nanowires serve as supports for growing CoS nanosheets, which not only make the CoS nanosheets well dispersed but also reduce their size and thickness. In addition, the intensive interaction between CoS and PPy endows the nanoarchitecture with high mechanical strength. Therefore, the constructed [email protected] nanocomposites feature abundant electroactive sites, high charge transport and transfer efficiencies, a short ion diffusion distance, and good structural stability. As a result, the optimized [email protected] nanocomposites as SC electrodes demonstrate specific capacities of 860C g−1 at 1 A g−1 and 595C g−1 at 20 A g−1, as well as a 92% initial capacity retention after 5000 cycles at 10 A g−1. Furthermore, a fabricated asymmetric supercapacitor (ASC) device with [email protected] nanocomposites as the positive electrode realizes a specific energy of 51.1 Wh kg−1 at 800 W kg−1, suggesting a promising potential for their practical application in SCs. This work may provide a feasible strategy for fabricating other metal sulfide/conducting polymer nanocomposites with enhanced charge storage capabilities as SC electrodes.

Recent progress in the genotyping of bovine tuberculosis and its rapid diagnosis via nanoparticle-based electrochemical biosensors.

Bovine tuberculosis (bTB) is considered a worldwide infectious zoonotic disease. Mycobacterium bovis causes bTB disease. It is one of the Mycobacterium tuberculosis complex (MTBC) members. MTBC is a clonal complex of close relatives with approximately 99.95% similarity. M. bovis is a spillover pathogen that can transmit from animals to humans and rarely from humans to animals with contact. Genotyping techniques are important to discriminate and differentiate between MTBC species. Spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) are widely used but they have some limitations. As an alternative, whole genome sequencing approaches have been utilized due to their high-resolution power. They are employed in typing M. bovis and explain the evolutionary and phylogenetic relationships between isolates. The control of bTB disease has attracted a large amount of attention. Rapid and proper diagnosis is necessary for monitoring the disease as an initial step for its control and treatment. Nanotechnology has a potential impact on the rapid diagnosis and treatment of bTB through the use of nanocarrier and metal nanoparticles (NPs). Special attention has been paid to voltammetric and impedimetric electrochemical strategies as facile, sensitive, and selective methods for the efficient detection of tuberculosis. The efficacy of these sensors is enhanced in the presence of NPs, which act as recognition and/or redox probes. Gold, silver, copper, cobalt, graphene, and magnetic NPs, as well as polypyrrole nanowires and multiwalled carbon nanotubes have been employed for detecting tuberculosis. Overall, NP-based electrochemical sensors represent a promising tool for the diagnosis of bTB.

Capacitors Based on Polypyrrole Nanowire Electrodeposits.

The electrochemical polymerization of polypyrrole nanowires is carried out using potentiodynamic and galvanostatic methods in order to enhance the performance of the modified electrodes as capacitor devices. The electrochemical, spectroscopic, and morphological properties are determined through cyclic voltammetry, Raman spectroscopy and scanning electron microscopy, respectively, corroborating the presence of PPy-nw in dimensions of 30 nm in diameter. Characterization as a capacitor revealed that the nanowire structure enhances key parameters such as specific capacitance with 60 times greater value than bulk polymer modification, in addition to a significant increase in stability. In this way, it is verified that electrodes modified with polypyrrole nanowires obtained in situ by electrochemical methods constitute an excellent candidate for the development of capacitors.

Enhancing Electrochemical Biosensor Performance for 17β-Estradiol Determination with Short Split-Aptamers.

Chronic exposure of 17β-estradiol (E2) even at low concentration can disorganize the endocrine system and lead to undesirable health problems in the long run. An electrochemical biosensor for rapid detection of E2 in water samples was successfully developed. The biosensor was based on split DNA aptamers attached onto poly (methacrylic acid-co-n butyl acrylate-succinimide) microspheres deposited on polypyrrole nanowires coated electrode (PPY/PMAA-NBA). The sandwich paired of split DNA aptamers used were truncated from 75 mer parent aptamers. These two strands of 12-mer and 14-mer split DNA aptamers were then immobilized on the PMAA-NBA microspheres. In the presence of E2, the split DNA aptamers formed an apt12-E2-apt14 complex, where the binding reaction on the electrode surface led to the detection of E2 by differential pulse voltammetry using ferrocyanide as a redox indicator. Under optimum conditions, the aptasensor detected E2 concentrations in the range of 1 × 10-4 M to 1 × 10-12 M (R2 = 0.9772) with a detection limit of 4.8 × 10-13 M. E2, which were successfully measured in a real sample with 97-104% recovery and showed a good correlation (R2 = 0.9999) with the established method, such as high-performance liquid chromatography. Interactions between short and sandwich-type aptamers (split aptamers) demonstrated improvement in aptasensor performance, especially the selectivity towards several potential interferents.

Decorating cobalt selenide nanoparticles on polypyrrole nanowires as nanocomposite electrodes for hybrid supercapacitors

• PPy@Co 0.85 Se nanocomposites are fabricated by a two-step electrochemical method. • Dispersed Co 0.85 Se nanoparticles are decorated on PPy nanowires growing on Ni foam. • PPy@Co 0.85 Se electrodes demonstrate improved rate capacities and cyclic stability. • The improved charge storage property arises from structural merits of nanocomposites. Cobalt selenide electrode materials for hybrid supercapacitors (HSCs) still suffer from the unsatisfactory rate performance and cyclic stability thanks to their limited electrical conductivity and poor structural stability. To address these issues, we here report on the construction of polypyrrole (PPy)@Co 0.85 Se nanocomposites that grow on Ni foam by a two-step electrochemical synthesis method. In such nanocomposites, well dispersed Co 0.85 Se nanoparticles are decorated on conductive PPy nanowires, which are featured by enhanced electrical conductivity, rich electroactive sites, easy adsorption/desorption and diffusion of electrolyte ions, and good mechanical stability. As a result, the obtained PPy@Co 0.85 Se nanocomposites give a maximum specific capacity of 827 C g −1 at 1 A/g, a capacity retention of 67 % at 20 A/g, and an initial capacity retention of 93 % after 5000 cycles at 10 A/g. Furthermore, a two-electrode HSC device is assembled with PPy@Co 0.85 Se as the positive electrode, which demonstrates an energy density of 51.9 Wh kg −1 at a power density of 812 W kg −1 as well as an initial capacity retention of 96 % after 5000 cycles at 5 A/g. These results showcase a great potential for future application of the synthesized PPy@Co 0.85 Se nanocomposites in HSCs, and our work may provide an efficient strategy for engineering other metal selenide-based electrode materials for HSCs.

Delocalized ferroelectric engineering of efficient photo-generated charge directional transfer for solar energy conversion into H2

Efficient transfer of photo-generated charges is a key kinetic factor of photocatalytic water (H2O) overall splitting. Herein, conversion of polypyrrole nanowire (PPyWs) insulator into delocalized ferroelectric semiconductor by transforming pyrrole into graphene structure containing azide (CNxFs) and subsequently integrating Ni2P (CNxFs/Ni2P) has been achieved for efficiently photocatalytic H2O overall splitting into hydrogen (H2) energy through a joint thermal and hydrothermal treatment. Theoretical prediction and detailed experimental results reveal that band gap of PPyWs insulator narrows from 4.63 eV to 2.36 eV of CNxFs (redox potentials: −0.85/1.51 V vs NHE), and the constructed delocalized ferroelectric CNxFs/Ni2P show efficient charge directional migration from generation sites to surface redox active sites. As a result, stoichiometric H2 and O2 evolution and a solar-to-H2 (STH) efficiency of 1.273 ± 0.051 % in photocatalytic H2O overall splitting have been completed under AM 1.5 G solar simulator irradiation along with gas bubbles under visible and even natural solar light. This research aims to solve the kinetic barrier of photocatalytic H2O splitting fundamentally through delocalized ferroelectric engineering, which will greatly boost the development of solar to H2 energy conversion.

Nickel phosphide nanoparticles decorated on polypyrrole nanowires as battery-type electrodes for hybrid supercapacitors

Metal phosphides as electrode materials for hybrid supercapacitors (HSCs) still face many challenges, such as insufficient electroactive sites, sluggish reaction kinetics, and low structural stability. To resolve these problems, we here integrate nickel phosphide (NiP) with polypyrrole (PPy) to construct PPy@NiP nanocomposites using a two-step electrochemical approach. Such nanocomposites are composed of amorphous NiP nanoparticles decorated on PPy nanowires. They are featured by increased amount of electroactive sites, enhanced electrical conductivity and electrolyte diffusion rate, and improved structural stability compared to the pure NiP particles. As a result, the PPy@NiP nanocomposites as HSC electrodes yield specific capacities of up to 364 mAh g−1 at 3 A g−1 and 159 mAh g−1 at 20 A g−1 as well as a 91% initial capacity retention over 5000 cycles at 10 A g−1. Their charge storage performance is superior to that of the pure NiP electrode. Furthermore, the fabricated PPy@NiP-based HSC device demonstrates an energy density of 57.3 Wh kg−1 at 798 W kg−1. This strategy for constructing PPy@NiP electrodes may be extended to other metal phosphide-based electrodes with enhanced charge storage performance for HSCs.

Bacterial Growth-Induced Tobramycin Smart Release Self-Healing Hydrogel for Pseudomonas aeruginosa-Infected Burn Wound Healing.

Burns are a common health problem worldwide and are highly susceptible to bacterial infections that are difficult to handle with ordinary wound dressings. Therefore, burn wound repair is extremely challenging in clinical practice. Herein, a series of self-healing hydrogels (QCS/OD/TOB/PPY@PDA) with good electrical conductivity and antioxidant activity were prepared on the basis of quaternized chitosan (QCS), oxidized dextran (OD), tobramycin (TOB), and polydopamine-coated polypyrrole nanowires (PPY@PDA NWs). These Schiff base cross-links between the aminoglycoside antibiotic TOB and OD enable TOB to be slowly released and responsive to pH. Interestingly, the acidic substances during the bacteria growth process can induce the on-demand release of TOB, avoiding the abuse of antibiotics. The antibacterial results showed that the QCS/OD/TOB/PPY@PDA9 hydrogel could kill high concentrations of Pseudomonas aeruginosa (PA), Staphylococcus aureus, and Escherichia coli in a short time and showed a bactericidal effect for up to 11 days in an agar plate diffusion experiment, while showing good in vivo antibacterial activity. Excellent and long-lasting antibacterial properties make it suitable for severely infected wounds. Furthermore, the incorporation of PPY@PDA endowed the hydrogel with near-infrared (NIR) irradiation assisted bactericidal activity of drug-resistant bacteria, conductivity, and antioxidant activity. Most importantly, in the PA-infected burn wound model, the QCS/OD/TOB/PPY@PDA9 hydrogel more effectively controlled wound inflammation levels and promoted collagen deposition, vascular generation, and earlier wound closure compared to Tegaderm dressings. Therefore, the TOB smart release hydrogels with on-demand delivery are extremely advantageous for bacterial-infected burn wound healing.

Insights on the capacitance degradation of polypyrrole nanowires during prolonged cycling

Polypyrrole (PPy) nanowires are widely used in supercapacitors due to their high faradaic pseudo-capacitance and specific surface areas. However, their rapid capacitance degradation is a key and broad issue that cannot be ignored. In this work, PPy/p-toluenesulfonate nanowires (PPy/pTS NWs) network films were electro-polymerized with different nanowire diameters (D) and film thicknesses (L). The effects of nanowire structure and the dissolved O2 (DO) in the media on the capacitance degradation behavior were investigated. With the cyclic voltammetry (CV) cycles increasing, the surface layer of PPy/pTS NWs was gradually damaged and dissolved with the loss of most doping anions, resulting in decreased specific capacitance. The high initial over-oxidation degree of PPy/pTS NWs and the high DO concentration significantly accelerated the degradation of PPy/pTS NWs during CV cycles. After the loss of most capacitance, PPy/pTS NWs network films were expanded with increased L but reduced D, displaying uniform degradation without fractured nanowires. The capacitance stability of PPy/pTS NWs could be enhanced by lowering the initial over-oxidation degree, inhibiting the loss of doping anions, and removing DO in the media.

Dual-Mode electrochemical biosensors based on Chondroitin sulfate functionalized polypyrrole nanowires for ultrafast and ultratrace detection of acetamiprid pesticide

The inappropriate and excessive use of pesticides poses a great challenge to human health. It is necessary to analyze pesticide residues efficiently, economically and quickly to minimize the risk of public safety issues. Herein, a dual-mode biosensor was proposed for ultrafast and ultratrace detection of acetamiprid (ACE). The polypyrrole nanowires (PPyNWs) was prepared using the guidance of CS by electrochemical method, which showed large electroactive surface area, excellent conductivity and high stability. After immobilization of ACE aptamer onto CS/PPyNWs, the biosensor can be effortlessly prepared. The ACE concentration can be measured by both the signal decrease of the chronocoulometry (CC) method and the chronoamperometry (CA) method. The dual-mode biosensor exhibited ultrafast detection speeds of 0.5 s and 2 s across 9 and 6 orders of magnitude linear ranges through CC and CA, respectively. More importantly, the biosensor was successfully applied to detect ACE residues in soil samples, proving the feasibility of the dual-mode biosensor for ACE detection in complex samples.

Simultaneously Improved Dielectric Constant and Breakdown Strength of PVDF-based Composites with Polypyrrole Nanowire Encapsuled Molybdenum Disulfide Nanosheets

Simultaneously Improved Dielectric Constant and Breakdown Strength of PVDF-based Composites with Polypyrrole Nanowire Encapsuled Molybdenum Disulfide Nanosheets

Charge Storage and Solar Rechargeable Battery Devices Based on Electrodes Electrochemically Modified with Conducting Polymer Nanowires.

In this work, the use of nanostructured conducting polymer deposits on energy-storing devices is described. The cathode and the anode are electrochemically modified with nanowires of polypyrrole and poly(3,4-ethylenedioxythiophene), respectively, prepared after the use of a mesoporous silica template. The effect of aqueous or ionic liquid medium is assayed during battery characterization studies. The nanostructured device greatly surpasses the performance of the bulk configuration in terms of specific capacity, energy, and power. Moreover, compared with devices found in the literature with similar designs, the nanostructured device prepared here shows better battery characteristics, including cyclability. Finally, considering the semi-conducting properties of the components, the device was adapted to the design of a solar-rechargeable device by the inclusion of a titanium oxide layer and cis-bis(isothiocyanate)-bis(2,2′-bipyridyl-4,4′-dicarboxylate) ruthenium (II) dye. The device proved that the nanostructured design is also appropriate for the implementation of solar-rechargeable battery, although its performance still requires further optimization.

A non-noble, low cost, multicomponent electrocatalyst based on nickel oxide decorated AC nanosheets and PPy nanowires for the direct methanol oxidation reaction

The multicomponent electrocatalyst is a low-cost composite material exhibiting excellent catalytic activity suitable for methanol oxidation reactions (MOR). In this work, we report a glassy carbon electrode modified nickel oxide nanospheres (NiO) decorated biomass-derived activated carbon (AC) nanosheets and polypyrrole (PPy) nanowire, electrocatalyst (NiO_AC@PPy/GCE) for direct methanol oxidation fuel cell (DMFC) application. The SEM micrographs reveal the nanosheets and nanowire-like morphology of AC and PPy decorated with NiO nanospheres which provide a high surface area with electrocatalytic activity, and stability for MOR. The NiO_AC@PPy/GCE exhibits a high current density of 551 mA/mg at a low onset potential of 0.5 V (vs Ag|AgCl) towards electro-oxidation of 0.5 M methanol (MeOH) in an alkaline medium. This superior performance of the NiO_AC@PPy/GCE over other reported metal-oxides based electrocatalysts is attributed to the synergistic effect of the NiO_AC@PPy electrocatalyst, wherein NiO provides electrocatalytic active sites for MOR via Ni2+/Ni3+ redox couple while the PPy and AC contribute towards the chemical stability and electrical conductivity of the electrode, respectively. The electrode shows 79% of capacity retention after 10,000 s of chronoamperometry displaying excellent chemical stability with reduced effect of CO intermediate poisoning at the electrode surface. This excellent stability and overall performance of the NiO_AC@PPy proves it as an ideal, low-cost non-noble electrocatalyst for DMFCs.

Fabrication of polypyrrole nanowire arrays-modified electrode for point-of-use water disinfection via low-voltage electroporation

Still ∼10% of world's population has no sustainable access to centralized water supply system, causing millions of deaths annually by waterborne diseases. Here, we develop polypyrrole nanowire arrays (PPyNWs)-modified electrodes by polymerization of pyrrole on graphite felt for point-of-use water disinfection via low-voltage electroporation. A flow-through mode is specially applied to alleviate diffusion barrier of pyrrole in the porous graphite felt for uniform PPyNWs growth. The flow-through disinfection device using the optimized PPyNWs electrode achieves above 4-log removal for model virus (MS2) and gram-positive/negative bacteria (E. faecalis and E. coli) at applied voltage of 1.0 V and fluxes below 1000 and 2500 L/m2/h. Electroporation is recognized as the dominant disinfection mechanism by using square-wave alternating voltage of ±1.0 V to eliminate the electrochemical reactions. In-situ sampling experiments reveal that anode acts as the main disinfection function due to its electric field attraction with negatively charged E. coli cells. The live/dead baclight staining experiments indicate an adsorption-desorption process of E. coli cells on anode, and the adsorption-desorption balance determines the disinfection abilities of PPyNWs anode. Under 1.0 V and 2000 L/m2/h, the disinfection device enables above 4-log E. coli removal in tap water within 7-day operation with energy consumption below 20 mJ/L, suggesting its sound application potential for point-of-use water disinfection.

Tailorable high-k and negative-k percolation behaviors in PPy/P(VDF-HFP) composites

Polymer-based composites with high permittivity and low loss are highly desirable for many applications such as embedded capacitors and pulse-power. In the meantime, percolating composites with negative permittivity can be promising candidates for metamaterials. In this paper, nanocomposites using conductive polypyrrole nanowires as fillers and poly(vinylidenefluoride-hexafluoropropylene) (P(VDF-HFP)) as matrix were prepared by a solution-casting method. The electrical properties were investigated in detail. Two types of percolation behavior were observed in the composites with increasing PPy content. The permittivity significantly enhanced when the PPy content exceeded high-dielectric percolation threshold (i.e. fhigh-k) due to the large number of microcapacitors formed by PPy fillers and P(VDF-HFP) matrix. With further increasing PPy content, tunable negative permittivity behavior was achieved due to the formation of conductive networks, this phenomenon can be regarded as a negative-dielectric percolation (i.e. negative-k percolation), which can be well described by Drude-Lorentz model. The realization of high permittivity and tunable negative permittivity in PPy/P(VDF-HFP) nanocomposites gives a new and efficient strategy toward high-k materials and random metamaterials.

Confined conductive and light-adsorbed network in metal organic frameworks (MIL-88B(Fe)) with enhanced photo-Fenton catalytic activity for sulfamethoxazole degradation

High light adsorption and fast charge separation are crucial for photo-Fenton catalytic activity of MOFs. Herein, bottom-up design was proposed to fabricate polypyrrole (PPyC) nanowires in MIL-88B(Fe) cages as photo-Fenton catalyst for Sulfamethoxazole (SMX) efficient degradation. Pyrrole was prior anchored into MIL-88B(Fe) cluster via Fe-N coordination, and then the additional monomer pyrrole was further triggered bottom-up polymerization in confined cages of MIL-88B(Fe) and formed PPyC@Py-MIL(Fe) composite. These PPyC nanowires were dispersed in Py-MIL(Fe) cages and tightly connected with MOFs clusters via Fe-N bonding. Characterization proved that: (1) Interfacial Fe-N can significantly promote the efficient electron transport from PPyC nanowires to Py-MIL(Fe), enhance optical absorption property, and construct strong Lewis acidic sites and ligand vacancies in PPyC@Py-MIL(Fe). (2) The confined PPyC nanowire via Fe-N connection remarkably promote photo-generated electron-hole separation, Fe2+|Fe3+ redox ability of MOF, and improved photo-electric corrosion ability. As a result, it significantly enhanced the photo-Fenton catalytic performance for SMX degradation. Catalytic oxidation was attributed to the generation of ‧OH species that oxidized 93% SMX in 60 min, showing ultra-rapid degradation and TOC removal rates of 33.7 min−1·mg·g−1 and 8.68 min−1·mg·g−1 respectively, which was about 4–220 times higher than those reported state-of-the-art catalysts. Additionally, the PPyC@Py-MIL(Fe) catalyst showed minimal loss in catalytic activity even after recycling for 10 times, exhibiting good recycling stability compared to many MOFs. Systematic analysis shown that in-situ anchored growth of polypyrrole in confined porous cages of MOF can effectively enhance the catalytic activity and stability of MIL-88B(Fe), and has great development potential applications for photo-Fenton catalytic degradation of organic pollutants.

Electrochemical formation of N–substituted polypyrrole nanowires, microwires and open microtubes and their decoration with copper structures

The substituted pyrrole monomer, N–(2–cyanoethyl)pyrrole, was electropolymerised in a 70% water and 30% ethanol solution with ClO4– and H2PO4– as the dopant species to give nanowires at short electropolymerisation times and microwires at longer deposition periods. On adding toluene to the electropolymerisation solution, hollow microtubes were formed. This was attributed to the adsorption of toluene droplets at the electrode surface which served to separate the dopants from the monomer, with the monomer being highly soluble in the toluene droplet and the inorganic dopants soluble in the water/ethanol mixture. As a result electropolymerisation was confined to the toluene-water/ethanol interface. These polymer systems exhibit redox activity with the oxidation wave centred at about 0.40 V vs SCE, and the broader reduction wave positioned between 0.75 V and 0.25 V vs SCE. Although N-substitution reduces the conductivity of the polymer, various copper deposits, including cubes, leaves and hierarchical structures were deposited at the microwires and microtubes using high overpotentials. The hierarchical structures were wrapped around the microtubes at considerable distances, typically 3–4 µm, from the substrate.

Two‐Dimensional‐Germanium Phosphide‐Reinforced Conductive and Biodegradable Hydrogel Scaffolds Enhance Spinal Cord Injury Repair

AbstractDeveloping biodegradable conductive hydrogels is of great importance for the repair of electroactive tissues, such as myocardium, skeletal muscle, and nerves. However, conventional conductive phase incorporation in composite hydrogels, such as polypyrrole, polyaniline, carbon nanotubes, graphene, and gold nanowires, which are non‐degradable materials, will exist in the body as foreign matter. Herein, an injectable hydrogel based on the integration of conductive and biodegradable germanium phosphide (GeP) nanosheets into an adhesive hyaluronic acid‐graft‐dopamine (HA‐DA) hydrogel matrix is explored, and the successful application of this biohybrid hydrogel in spinal cord injury (SCI) repair is demonstrated. The incorporation of polydopamine (PDA)‐modified GeP nanosheets (GeP@PDA) into HA‐DA hydrogel matrix significantly improves the conductivity of HA‐DA/GeP@PDA hydrogels. The conductive HA‐DA/GeP@PDA hydrogels can accelerate the differentiation of neural stem cells (NSC) into neurons in vitro. In a rat SCI complete transection model, the in vivo implanted HA‐DA/GeP@PDA hydrogel is found to improve the recovery of locomotor function significantly. The immunohistofluorescence investigation suggests that the HA‐DA/GeP@PDA hydrogels promote immune regulation, endogenous angiogenesis, and endogenous NSC neurogenesis in the lesion area. The strategy of integrating conductive and biodegradable GeP nanomaterials into an injectable hydrogel provides new insight into designing advanced biomaterials for SCI repair.