Search Results (424)

Electrically conductive hydrogels are gaining attention owing to their applications in biosensing, cellular interfaces, and tissue engineering. However, conventional hydrogels often lack adequate electrical conductivities. Here, we present two novel conductive alginate-based hydrogels designed for extrusion-based 3D bioprinting: (i) covalently synthesized alginate–polypyrrole (alginate–PPy) via EDC/NHS-mediated conjugation with 3-aminopropyl pyrrole, and (ii) nanoparticle-reinforced alginate blended with polypyrrole nanoparticles (alginate@PPy-NP). Both systems exhibited shear-thinning behavior, tunable viscoelasticity, and excellent printability. Alginate@PPy-NP demonstrated superior compressive strength and shape fidelity, whereas alginate–PPy showed enhanced elastic moduli (G′/G″), reflecting a more uniform gel network. Electrical conductivity increased with increasing pyrrole content in both formulations. Optimization of the composition and printing conditions enabled the fabrication of fibroblast-laden constructs with high structural integrity. This work highlights the potential of alginate–polypyrrole hydrogels as customizable, conductive bioinks for 3D bioprinting in regenerative medicine. Full article

Background/Objectives: Photothermal therapy (PTT) is an emerging minimally invasive strategy in biomedicine that converts near-infrared (NIR) light into localized heat for the targeted inactivation of pathogens and tumor cells. Methods and Results: In this study, we report the synthesis and characterization of thermoresponsive nanogels composed of poly (N-isopropylacrylamide-co-N-isopropylmethylacrylamide) (PNIPAM-co-PNIPMAM) semi-interpenetrated with polypyrrole (PPy), yielding monodisperse particles of 377 nm diameter. Spectroscopic analyses—including ¹H-NMR, FTIR, and UV-Vis—confirmed successful copolymer formation and PPy incorporation, while TEM images revealed uniform spherical morphology. Differential scanning calorimetry established a volumetric phase transition temperature of 38.4 °C, and photothermal assays demonstrated a ΔT ≈ 10 °C upon 10 min of 850 nm NIR irradiation. In vitro antimicrobial activity tests against Pseudomonas aeruginosa (ATCC 15692) showed a dose-time-dependent reduction in bacterial viability, with up to 4 log CFU/mL. Additionally, gentamicin-loaded nanogels achieved 38.7% encapsulation efficiency and exhibited stimulus-responsive drug release exceeding 75% under NIR irradiation. Conclusions: Combined photothermal and antibiotic therapy yielded augmented bacterial killing, underscoring the potential of PPy-interpenetrated nanogels as smart, dual-mode antimicrobials. Full article

This review is different from previous studies focusing on polypyrrole (PPy) in universal fields such as sensors and supercapacitors. It is the first TO systematically review the specific applications of PPy-based electrospun nanofiber composites in the biomedical field, focusing on its biocompatibility regulation mechanism and tissue repair function. Although PPy exhibits exceptional electrical conductivity, redox activity, and biocompatibility, its clinical translation is hindered by processing challenges and poor degradability. These limitations can be significantly mitigated through composite strategies with degradable nanomaterials, enhancing both process compatibility and biofunctionality. Leveraging the morphological similarity between electrospun nanofibers and the natural extracellular matrix (ECM), this work comprehensively analyzes the topological characteristics of three composite fiber architectures—randomly distributed, aligned, and core–shell structures—and elucidates their application mechanisms in nerve regeneration, skin repair, bone mineralization, and myocardial tissue reconstruction (e.g., facilitating oriented cell migration and regulating differentiation through specific signaling pathway activation). The study further highlights critical challenges in the field, including PPy’s poor solubility, limited spinnability, insufficient mechanical strength, and scalability limitations. Future efforts should prioritize the development of multifunctional gradient composites, intelligent dynamic-responsive scaffolds, and standardized biosafety evaluation systems to accelerate the substantive translation of these materials into clinical applications. Full article

The rapid development of energy storage technologies has led to an increasing demand for high-performance electrode materials that can enhance both the energy density and the cycling stability of batteries. In this study, polypyrrole (PPy) nanorods with partial hollow features are utilized as a conductive and flexible framework for the in situ growth of VO₂ nanospheres via a simple hydrothermal method, forming a well-defined core–shell PPy/VO₂ nanocomposite. This hierarchical nanostructure combines the excellent electrical conductivity and mechanical flexibility of PPy with the high theoretical capacity of VO₂, creating a synergistic effect that significantly enhances the electrochemical performance. The well-integrated interface between PPy and VO₂ reduces interfacial resistance, promotes efficient electron and ion transport, and improves the overall energy conversion efficiency. Electrochemical testing reveals that the PPy/VO₂ nanocomposite delivers a high specific capacity of 413 mAh g⁻¹ at 100 mA g⁻¹ and retains 87.2% of its initial capacity after 1200 cycles, demonstrating exceptional rate capability and long-term cycling stability. This work provides a versatile strategy for designing high-performance cathode materials and highlights the promising potential of PPy/VO₂ nanocomposites for next-generation high-energy-density aqueous zinc-ion batteries. Full article

In this study, membranes of collagen–chitosan (C-Ch) in combination with conductive polymers (CPs) such as polyaniline (Pani) and polypyrrole (Ppy) were obtained by electrospinning using non-toxic solvents such as PBS and ethanol. The change in the morphology after swelling was observed by SEM, while an FTIR analysis showed specific interactions between C-Ch and CP. Mechanical tests showed that C-Ch/Ppy exhibited more elastic behavior and a better stress distribution compared to C-Ch/Pani. The diffusion of Na⁺ and Ca²⁺ ions through the membranes was evaluated and showed a greater resistance for Ca²⁺ in both membrane types. Preliminary biocompatibility testing with H9C2 cells showed a successful cell adhesion to the membranes. These results emphasize the potential of C-Ch/Pani composites for electrically active scaffolds and of C-Ch/PPy composites for applications in mechanically dynamic tissue-specific regeneration. Full article

Bioelectronic medicines record biological signals and provide electrical stimulation for the treatment of diseases. Advanced bioelectronic therapies require the development of electrodes that match the softness of the implanted tissues, as the present metal electrodes do not meet this condition. The objective of the present work was to investigate whether the electroconductive polymer polypyrrole (PPy) could be used for fabricating such electrodes, as PPy is several orders softer than metals. For this purpose, we here investigated if electrodes made using coatings and films of PPy doped with naphthalin-2-sulfonic acid (PPy/N) are capable to record and elicit by stimulation cardiac monophasic action potentials (MAPs) and if PPy/N is also biocompatible. The results of this study showed that the tested PPy/N electrodes are capable of recording MAPs almost identical to the MAPs recorded with platinum electrodes and eliciting stimulation-evoked MAPs almost identical to the spontaneous MAPs. In addition, we show here that the cell cultures that we used for biocompatibility tests grew in a similar manner on PPy/N and platinum substrates. We, therefore, conclude that PPy/N coatings and films have recording and electrical stimulation capabilities that are similar to those of platinum electrodes and that PPy/N substrates are as biocompatible as the platinum substrates. Full article

Conducting polymer (CP) nanoparticles have emerged as innovative materials for biomedical applications, particularly due to their safe interaction with biological systems. This study focuses on the synthesis, morphological, and spectroscopic characterization of polypyrrole nanoparticles (PPy-NPs) as photoactivatable agents under near-infrared (NIR) radiation for the inactivation of pathogenic bacteria. We successfully synthesized uniform nanoparticles (~180 nm) with strong absorption in the NIR region. A comprehensive characterization was performed using electron microscopy, dynamic light scattering, X-ray diffraction, and UV–Vis and infrared spectroscopy. The microbiological evaluation focused on elucidating the inactivation mechanism of Pseudomonas aeruginosa, particularly through oxidative stress induction, metabolic activity alteration, and cell membrane disruption. Our results highlight the significant potential of PPy-NPs as photoactivatable agents for the targeted inactivation of pathogenic microorganisms, underscoring their promising applications in antimicrobial surface coatings. Full article

In this work, conductive polymers, i.e., polyaniline (PANI) and its copolymers with polypyrrole (PPy), polythiophene (PTh), and poly (3,4-ethylenedioxythiophene) (PEDOT) were synthesized following chemical oxidative polymerization methods and used in the construction of supercapacitor devices. These conductive copolymers were characterized by structural (FTIR, XRD), morphological (FESEM), electrochemical (CV and GCD), and impedance spectroscopy studies. The PANI-PPy copolymer showed higher sp. capacitance of 420 F/g and cyclic capacitive retention of 97.8% compared to the other copolymers. Additionally, Tafel extrapolation studies demonstrated that the PANI-PEDOT had the lowest corrosion rate. To further assess performance, asymmetric supercapacitor devices (ASDs) were fabricated using prepared materials. GCD analysis demonstrated that the PANI-PTh//AC device achieved a sp. capacitance of 81 F/g and power density of 550 W/kg, while the PANI-PPy//AC device exhibited a capacitance of 69 F/g. PANI-PTh//AC device shows superior performance over other electrode configurations. Full article

Polypyrrole (PPy)-doped bismuth calcium manganite (BCM) nanocomposites were synthesized by chemical polymerization. The amorphous nature of the polypyrrole and the monoclinic crystal structure of the BCM particles (35–65 nm) were confirmed by various microstructural, X-ray powder, and spectroscopy techniques. The DC conductivity analysis via the correlated barrier-hopping (CBH) model and Mott’s variable-range hopping (MVRH) model showed that the nanocomposites exhibited ionic conduction. Activation energies, evaluated from the Arrhenius plots, showed that PPy/BCM-30 (30 wt.% of BCM) had the minimum value of 0.09 eV, indicating maximum conductivity and normal NTCR behavior, with resistance decreasing with temperature. The CBH model described the conduction process, and the AC conductivity measurements indicated that the conductivity was frequency-independent at lower frequencies but became dispersive and frequency-dependent at higher frequencies, conforming to Jonscher’s power law. The study revealed that the transport of electrical charge in the material followed the correlated barrier-hopping (CBH) model. These results demonstrate how promising PPy/BCM nanocomposites are for energy storage, sensors, and electronic materials. Full article

This study investigates the efficient and recyclable use of polymer-based membrane materials in wastewater treatment, focusing on calcium-based montmorillonite (Ca-MMT), pyrrole (Py), and polypropylene (PP). Through sodium activation, organic modification, pyrrole intercalation, and in situ polymerization, polypyrrole/montmorillonite (PPy/MMT) was synthesized. A polypyrrole/montmorillonite/polypropylene composite membrane (PPy/MMT/PP) was then fabricated using melt compression and coating techniques for pollutant adsorption. The modification of montmorillonite by PPy was examined, alongside the morphology, composition, and structure of PPy/MMT/PP. The membrane’s adsorption performance for methyl orange and Pb²⁺ was evaluated, with a focus on cyclic adsorption. The results showed that PPy increased the interlayer spacing of montmorillonite from 1.23 nm to 1.74 nm and enhanced its specific surface area by 99.424 m²/g. The composite membrane exhibited improved wettability and adsorption capacity, achieving removal rates of 95.98% for methyl orange and 88.48% for Pb²⁺, following pseudo-second-order kinetics. The membrane demonstrated recyclability, maintaining efficient adsorption/desorption over three cycles. This work provides valuable insights and technical support for sustainable wastewater treatment using polymer-based membranes. Full article

A composite (N-rGO@ppy) of N-doped reduced graphene oxide (N-rGO) coated with polypyrrole (ppy) particles was successfully synthesized. The incorporation of N-rGO significantly mitigates the aggregation of ppy synthesized in situ, and the doped N atoms improve the conductivity of graphene oxide (GO), thereby enhancing N-rGO@ppy’s redox properties. Firstly, a glassy carbon electrode (GCE) modified with N-rGO@ppy (N-rGO@ppy/GCE) was used in combination with a bismuth film and square-wave anodic stripping voltammetry (SWASV) for the simultaneous trace analysis of Pb²⁺ and Cd²⁺. N-rGO@ppy/GCE exhibited distinct stripping peaks for Pb²⁺ and Cd²⁺, with a linear range of 1 to 500 μg L⁻¹. The limits of detection (LODs) were found to be 0.080 μg L⁻¹ for Pb²⁺ and 0.029 μg L⁻¹ for Cd²⁺, both of which are significantly below the standards set by the World Health Organization (WHO). Subsequently, the same electrochemical sensing strategy was adapted to a more portable screen-printed electrode (SPE) to accommodate the demand for in situ detection. The performance of N-rGO@ppy/SPE for analyzing Pb²⁺ and Cd²⁺ in actual samples, such as drinking water, milk, and honey, showed results consistent with those obtained from conventional graphite furnace atomic absorption spectrometry (GFAAS). Full article

In the development of flexible smart electronics, fabricating electrodes with optimized architectures to achieve superior electrochemical performance remains a significant challenge. This study presents a two-step synthesis and characterization of a polypyrrole (PPy)-MnO₂/carbon cloth (CC) nanocomposite. The MnO₂/CC substrate was first prepared via the hydrothermal method, followed by uniform PPy coating through vapor-phase polymerization in the presence of an oxidizing agent. Electrochemical measurements revealed substantial enhancement in performance, with the specific capacitance increasing from 123.1 mF/cm² for the MnO₂/CC composite to 324.5 mF/cm² for the PPy/MnO₂/CC composite at a current density of 2.5 mA/cm². This remarkable improvement can be attributed to the synergistic effects between the conductive PPy polymer and MnO₂/CC substrate and the formation of additional ion transport channels facilitated by the PPy coating. This work provides valuable insights for designing high-performance electrode materials and advances the development of composite-based energy storage devices. Full article

Organic hybrid materials are gaining traction as electrode candidates for energy storage due to their structural tunability and environmental compatibility. This study investigates polyimide/carbon nanotube/polypyrrole (PI/CNTs/PPy) hybrid nanocomposites, focusing on the correlation between thermal imidization temperature, polypyrrole deposition time, and the resulting electrochemical properties. By modulating PI processing temperatures (90 °C, 180 °C, 250 °C) and PPy deposition durations (60–700 s), this research uncovers critical structure–function relationships governing charge storage behavior. Scanning electron microscopy and electrochemical impedance spectroscopy reveal that low-temperature imidization preserves porosity and enables ion-accessible pathways, while moderate PPy deposition enhances electrical conductivity without blocking pore networks. The optimized composite, processed at 90 °C with 60 s PPy deposition, demonstrates superior specific capacitance (850 F/g), high redox contribution (~70% of total charge), low charge transfer resistance, and enhanced energy/power density. In contrast, high-temperature processing and prolonged PPy deposition result in structural densification, increased resistance, and diminished performance. These findings highlight a synergistic design approach that leverages partial imidization and controlled doping to balance ionic diffusion, electron transport, and redox activity. The results provide a framework for developing scalable, high-performance, and sustainable electrode materials for next-generation lithium-ion batteries and supercapacitors. Full article

In recent years, conductive polymer hydrogels based on polypyrrole (PPy) combined with electrical stimulation (ES) have emerged as a promising approach for chronic wound repair. However, in practical applications, PPy often exhibits limitations such as poor water dispersion, weak inherent conductivity and a lack of biological functionality. To address these challenges, this study proposes an innovative design of a conductive hydrogel that employs a natural biopolymer, lignin sulfonate (Lgs), as both a dispersant and dopant for PPy, while incorporating silver nanoparticles (Ag NPs) to confer the hydrogel antibacterial properties. The results showed that the water dispersion of PPy was significantly improved, and the conductivity of the hydrogel was as high as 2.82 ± 0.04 mS/cm through the double conduction mechanism of PPy and Ag NPs. The hydrogel exhibited antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and the antibacterial rate could exceed 90%. In vitro tests demonstrated that the hydrogel exhibited good biocompatibility, adhesion ability (7.97 ± 0.56 kPa) and hemostatic ability. Furthermore, in vivo animal experiments showed that the hydrogel combined with ES achieved 93.71 ± 2.46% wound closure within 14 days, which can significantly accelerate wound healing, promote collagen deposition and epithelial tissue regeneration. These findings demonstrate that the developed hydrogel can serve as an effective platform for ES-assisted chronic wound repair. Full article

Gold nanoparticles–cuprous oxide/reduced graphene oxide/polypyrrole (AuNPs-Cu₂O/rGO/PPy) hybrid nanocomposites were synthesized for surface acoustic wave (SAW) sensors, achieving high sensitivity (2 Hz/ppb), selectivity, and fast response (~2 min) at room temperature. The films, deposited via spin-coating, were characterized by SEM, EDS, and XRD, revealing a rough, wrinkled morphology beneficial for gas adsorption. The sensor showed significant frequency shifts to NH₃, enhanced by AuNPs, Cu₂O, rGO, and PPy. It had a 6.4-fold stronger response to NH₃ compared to CO₂, H₂, and CO, confirming excellent selectivity. The linear detection range was 12–1000 ppb, with a limit of detection (LOD) of 8 ppb. Humidity affected performance, causing negative frequency shifts, and sensitivity declined after 30 days due to resistivity changes. Despite this, the sensor demonstrated excellent NH₃ selectivity and stability across multiple cycles. In simulated breath tests, it distinguished between healthy and patient-like samples, highlighting its potential as a reliable, non-invasive diagnostic tool. Full article