Flexible Organic Photovoltaic-Powered Hydrogel Bioelectronic Dressing With Biomimetic Electrical Stimulation for Healing Infected Diabetic Wounds.

Electrical stimulation (ES) is proposed as a therapeutic solution for managing chronic wounds. However, its widespread clinical adoption is limited by the requirement of additional extracorporeal devices to power ES-based wound dressings. In this study, a novel sandwich-structured photovoltaic microcurrent hydrogel dressing (PMH dressing) is designed for treating diabetic wounds. This innovative dressing comprises flexible organic photovoltaic (OPV) cells, a flexible micro-electro-mechanical systems (MEMS) electrode, and a multifunctional hydrogel serving as an electrode-tissue interface. The PMH dressing is engineered to administer ES, mimicking the physiological injury current occurring naturally in wounds when exposed to light; thus, facilitating wound healing. In vitro experiments are performed to validate the PMH dressing's exceptional biocompatibility and robust antibacterial properties. In vivo experiments and proteomic analysis reveal that the proposed PMH dressing significantly accelerates the healing of infected diabetic wounds by enhancing extracellular matrix regeneration, eliminating bacteria, regulating inflammatory responses, and modulating vascular functions. Therefore, the PMH dressing is a potent, versatile, and effective solution for diabetic wound care, paving the way for advancements in wireless ES wound dressings.

Adhesive Ion-Conducting Hydrogel Strain Sensor with High Sensitivity, Long-Term Stability, and Extreme Temperature Tolerance.

Ion-conducting hydrogels with excellent flexibility and ductility have great potential in human movements monitoring. However, some obstacles, including a small detection range, low sensitivity, low electrical conductivity, and poor stability under extreme conditions, impede their use as sensors. Herein, an ion-conducting hydrogel comprising acrylamide (AM), lauryl methacrylate (LMA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and a water/glycerol binary solvent (named the AM-LMA-AMPS-LiCl (water/glycerol) hydrogel) is designed, which exhibits an enlarged detection range of 0%-1823% and improved transparency. Notably, the ion channel constructed using AMPS and LiCl significantly improves the sensitivity (gauge factor = 22.15 ± 2.86) of the hydrogel. The water/glycerol binary solvent endows the hydrogel with electrical and mechanical stability under extreme conditions (70 and -80 °C). Furthermore, the AM-LMA-AMPS-LiCl (water/glycerol) hydrogel exhibits antifatigue properties for 10 cycles (0%-1000%) because of noncovalent interactions such as hydrophobic interactions and hydrogen bonding. The hydrogel can be used to monitor human movements such as joint bending and perceive subtle discrepancies such as different joint bending speeds and angles, showing its great potential application in human movement monitoring, electronic skin, and wearable devices.

Single-Ion-Conducting Hydrogel Electrolytes Based on Slide-Ring Pseudo-Polyrotaxane for Ultralong-Cycling Flexible Zinc-Ion Batteries.

Flexible zinc-ion batteries (ZIBs) with high capacity and long cycle stability are essential for wearable electronic devices. Hydrogel electrolytes have been developed to provide ion-transfer channels while maintaining the integrity of ZIBs under mechanical strain. However, hydrogel matrices are typically swollen with aqueous salt solutions to increase ionic conductivity, which can hinder intimate contact with electrodes and reduce mechanical properties. To address this, a single-Zn-ion-conducting hydrogel electrolyte (SIHE) is developed by integrating polyacrylamide network and pseudo-polyrotaxane structure. The SIHE exhibits a high Zn2+ transference number of 0.923 and a high ionic conductivity of 22.4 mS cm-1 at room temperature. Symmetric batteries with SIHE demonstrate stable Zn plating/stripping performance for over 160 h, with a homogenous and smooth Zn deposition layer. Full cells with La-V2 O5 cathodes exhibit a high capacity of 439 mA h g-1 at 0.1 A g-1 and excellent capacity retention of 90.2% after 3500 cycles at 5 A g-1 . Moreover, the flexible ZIBs display stable electrochemical performance under harsh conditions, such as bending, cutting, puncturing, and soaking. This work provides a simple design strategy for single-ion-conducting hydrogel electrolytes, which could pave the way for long-life aqueous batteries.

Electrically Conducting Hydrogels for Health care: Concept, Fabrication Methods, and Applications.

Electrically conducting hydrogels are gaining increasing attention due to their potential application in smart patches, biosensors, functional tissue engineering scaffolds, wound management, and implants. The current review focuses on these novel materials, their synthesis routes, and their composites. Special attention is paid to fabrication routes to produce functional composites with organic and inorganic components. The design of conductive hydrogels leads to inheritance of the advantages of each component and offers new features from the synergistic effects between the components, thus opening new application areas. The review also discusses the emerging role of 3D printing as an advanced approach toward new design, functionality, and material combination possibilities. The issue of lack of the spatial control with current techniques is highlighted, and possible new routes to solve it are discussed. The review will provide readers with knowledge tool to select appropriate methodology for designing desired hydrogel material composites.

A Self-Healing, All-Organic, Conducting, Composite Peptide Hydrogel as Pressure Sensor and Electrogenic Cell Soft Substrate.

Conducting polymer hydrogels (CPHs) emerge as excellent functional materials, as they harness the advantages of conducting polymers with the mechanical properties and continuous 3D nanostructures of hydrogels. This bicomponent organization results in soft, all-organic, conducting micro-/nanostructures with multifarious material applications. However, the application of CPHs as functional materials for biomedical applications is currently limited due to the necessity to combine the features of biocompatibility, self-healing, and fine-tuning of the mechanical properties. To overcome this issue, we choose to combine a protected dipeptide as the supramolecular gelator, owing to its intrinsic biocompatibility and excellent gelation ability, with the conductive polymer polyaniline (PAni), which was polymerized in situ. Thus, a two-component, all-organic, conducting hydrogel was formed. Spectroscopic evidence reveals the formation of the emeraldine salt form of PAni by intrinsic doping. The composite hydrogel is mechanically rigid with a very high storage modulus ( G') value of ∼2 MPa, and the rigidity was tuned by changing the peptide concentration. The hydrogel exhibits ohmic conductivity, pressure sensitivity, and, importantly, self-healing features. By virtue of its self-healing property, the polymeric nonmetallic hydrogel can reinstate its intrinsic conductivity when two of its macroscopically separated blocks are rejoined. High cell viability of cardiomyocytes grown on the composite hydrogel demonstrates its noncytotoxicity. These combined attributes of the hydrogel allowed its utilization for dynamic range pressure sensing and as a conductive interface for electrogenic cardiac cells. The composite hydrogel supports cardiomyocyte organization into a spontaneously contracting system. The composite hydrogel thus has considerable potential for various applications.

Amperometric glucose biosensing performance of a novel graphene nanoplatelets-iron phthalocyanine incorporated conducting hydrogel.

Herein, a novel one step synthesis of multicomponent three dimensional polyacrylic acid (PAA) based conducting hydrogel (CH) incorporated with iron phthalocyanine functionalised graphene nanoplatelets (GPL-FePc) is reported. An amperometric glucose biosensor was fabricated by the immobilization of glucose oxidase (GOx) onto the synthesised PAA-VS-PANI/GPL-FePc-CH (where VS-PANI is vinyl substituted polyaniline). Scanning electron microscopy reveals the presence of three dimensional microporous structure with estimated pore size of 19 µm. The 5-(trifluoromethyl)-2-mercaptopyridine substitution onto FePc enabled the solubility of FePc in water and controls the aggregation of GPL-FePc in the synthesised CH. A sharp peak around 699 nm in UV-visible spectra confirms the presence of incorporated GPL-FePc into CH. Cyclic voltammogram of the synthesised CH biosensor exhibited well defined redox peaks with a ΔEp value of 0.26 V in Fe(CN)63-/4- bench mark solution. The fabricated PAA-VS-PANI/GPL-FePc/GOx-CH amperometric biosensor resulted in remarkable detection sensitivity of 18.11 µA mM-1 cm-2 with an average response time of ∼1 s, linearity from 1 to 20 mM, and low detection limit of 6.4 µM for the determination of glucose.

Near-infrared light-responsive electrochemical protein imprinting biosensor based on a shape memory conducting hydrogel.

Herein, a near-infrared (NIR) light-responsive imprinting biosensor with excellent conductivity and tensibility was designed by incorporation graphene oxide/polyaniline (GO/PANI) with thermo-responsive poly(N-isopropylacrylamide) hydrogel (PNiPAAm) on a glassy carbon electrode (GCE). In this design, polyaniline (PANI) nanofiber modifies with graphene oxide (GO) acts as a physically cross-linker, providing hydrogen bond interaction with amide groups in the PNiPAAm. It is functioned to enhance the strength of imprinted hydrogel networks. Thus, the imprinted hydrogel biosensor incorporation of GO/PANI nanocomposite exhibited excellent mechanical performance and NIR light-responsive characteristic. As a NIR radiation trigger gate, the obtained biosensor not only has a function of IR-based cleaning toward bovine serum albumin (BSA) in the absence of elution solution, but also a function of proteins releasing and uptaking, basing on reversibly conformational changes with 808 nm NIR light. Simultaneously, the responsive processes were electronically monitored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and verified by scanning electron microscopy (SEM). Moreover, the proposed GO/PANI nanocomposite imprinted biosensor exhibited excellent characteristics along with high conductivity and tensibility, long-term stability, and wide linear range, performing great promising for preparing remote NIR light-driven extraction protein smart devices.

Characterization and repair effect of supramolecular conducting hydrogel carrying ligustrazine on spinal cord injury in rats / 中国组织工程研究

BACKGROUND:Based on the concept of the combination of medicine and industry and the advantages of traditional Chinese medicine treatment,the construction of a new composite material loaded with the effective active ingredient of traditional Chinese medicine is a hot research spot in the repair of spinal cord injury,and is expected to become an effective means to solve this problem. OBJECTIVE:To observe the effect of supramolecular conducting hydrogel carrying ligustrazine in repairing spinal cord injury in rats. METHODS:The supramolecular conducting hydrogel carrying ligustrazine was prepared and its microstructure,conductivity,rheology,swelling rate and in vitro release performance were characterized.45 SD rats were divided into 3 groups by random number table method,with 15 rats in each group:no spinal cord injury in the sham operation group;spinal cord injury model was established in the model group;and supramolecular conducting hydrogel carrying ligustrazine was injected into the spinal cord injury area after model establishment in hydrogel group.BBB score was used to evaluate the recovery of hind limb motor function of each group before and 1,7,14,21 and 28 days after modeling,respectively.28 days after the model establishment,the spinal cord tissues were collected and analyzed by hematoxylin-eosin staining,immunohistochemical staining and western blot assay. RESULTS AND CONCLUSION:(1)Under scanning electron microscopy,the supramolecular conducting hydrogel with ligustrazine displayed a three-dimensional micrometer-scale porous network structure with high porosity and a pore size of approximately 100 μm.The conductivity of the hydrogel was 7.66 S/m;the swelling rate was 3 764.42%,and it had certain mechanical stability and injection property.In vitro sustained release experiments demonstrated that the supramolecular conducting hydrogel with ligustrazine sustainably released ligustrazine for more than 800 hours.With the extension of time,the cumulative release of ligustrazine exhibited an increasing trend.(2)With the extension of modeling time,the hind limb motor function gradually recovered in the model group and the hydrogel group,and the hind limb motor function of the hydrogel group was better than that of the model group on 14,21,and 28 days after modeling(P<0.05).Hematoxylin-eosin staining demonstrated that the spinal cord tissue of the model group had cavities and a large number of inflammatory cells could be seen at the stump.In the hydrogel group,some inflammatory cells were infiltrated in the injured area of the spinal cord;the void area of the injured area was reduced;neuron cells appeared in the junction area,and the tissue arrangement was relatively neat.Immunohistochemical staining and western blot assay exhibited that the expression of tumor necrosis factor α and interleukin-6 protein in the rat spinal cord of the hydrogel group was lower than that in the model group(P<0.05),and the expression of neuronal nuclear antigen protein was higher than that in the model group(P<0.05).(3)These findings confirm that the supramolecular conducting hydrogel carrying ligustrazine can promote the repair of spinal cord injury.

Injectable conductive collagen/alginate/polypyrrole hydrogels as a biocompatible system for biomedical applications.

Recently, Injectable Conducting Hydrogel (ICH) systems have gained much attention for tissue engineering and regenerative medicine. These systems can promote the regeneration of tissues responding to electrical responses. In this study, a novel ICH system was introduced. To achieve this system, firstly, a soluble non-toxic polypyrrole (PPy) synthesized by grafting pyrrole on alginate (Alg) backbone (Alg-graft-PPy), and then, ICH systems were prepared by the given ratios of Alg-graft-PPy, Alg, and collagen (Col). Three different amounts of Col (0.5, 1, and 1.5 mg/ml) were added to the system including Alg-graft-PPy: Alg wt. % with the ratios of 20:80 and 30:70. FTIR spectroscopy, electrical conductivity, viscosity, syringeability, gelation time, and MTT assay were performed in order to characterize the produced hydrogels. Due to the rheological behavior of 20:80 (Alg-graft-PPy: Alg wt. %), it was recognized more suitable to inject. Also this system associated with 0.5 mg/ml Col introduced as the best sample with respect to its viscosity and injectability. This ICH system has shown high conductivity in addition to a good level of cell viability and syringeability. With respect to properties of the produced ICH system, it can be applied for bone, nerve, muscle and cardiac cells, which respond to electrical impulses.