Antibacterial hydrogel has received extensive attention in soft tissue repair, especially preventing infections those associated with impaired wound healing. However, it is challenging in developing an inherent antibacterial hydrogel integrating with excellent cell affinity and superior mechanical properties. Inspired by the mussel adhesion chemistry, a contact-active antibacterial hydrogel is proposed by copolymerization of methacrylamide dopamine (MADA) and 2-(dimethylamino)ethyl methacrylate and forming an interpenetrated network with quaternized chitosan. The reactive catechol groups of MADA endow the hydrogel with contact intensified bactericidal activity, because it increases the exposure of bacterial cells to the positively charged groups of the hydrogel and strengthens the bactericidal effect. MADA also maintains the good adhesion of fibroblasts to the hydrogel. Moreover, the hybrid chemical and physical cross-links inner the hydrogel network makes the hydrogel strong and tough with good recoverability. In vitro and in vivo tests demonstrate that this tough and contact-active antibacterial hydrogel is a promising material to fulfill the dual functions of promoting tissue regeneration and preventing bacterial infection for wound-healing applications.

An efficient polymer moist-electric generator is developed on the basis of conventional polyelectrolyte membrane to output considerable electric power under moisture.

The term “zwitterionic polymers” refers to polymers that bear a pair of oppositely charged groups in their repeating units. When these oppositely charged groups are equally distributed at the molecular level, the molecules exhibit an overall neutral charge with a strong hydration effect via ionic solvation. The strong hydration effect constitutes the foundation of a series of exceptional properties of zwitterionic materials, including resistance to protein adsorption, lubrication at interfaces, promotion of protein stabilities, antifreezing in solutions, etc. As a result, zwitterionic materials have drawn great attention in biomedical and engineering applications in recent years. In this review, we give a comprehensive and panoramic overview of zwitterionic materials, covering the fundamentals of hydration and nonfouling behaviors, different types of zwitterionic surfaces and polymers, and their biomedical applications.

Conductive hydrogels (CHs) have gained significant attention for their wide applications in biomedical engineering owing to their structural similarity to soft tissues. However, designing CHs that combine biocompatibility with good mechanical and electrical properties is still challenging. Herein, we report a new strategy for the fabrication of tough CHs with excellent conductivity, superior mechanical properties, and good biocompatibility by using chitosan framework as molecular templates for controlling conducting polypyrrole (PPy) nanorods in situ formation inside the hydrogel networks. First, polyacrylamide/chitosan (CS) interpenetrating polymer network hydrogel was synthesized by UV photopolymerization; second, hydrophobic and conductive pyrrole monomers were absorbed and fixed on CS molecular templates and then polymerized with FeCl3 in situ inner hydrophilic hydrogel network. This strategy ensured that the hydrophobic PPy nanorods were uniformly distributed and integrated with the hydrophilic polymer phase to form highly interconnected conductive path in the hydrogel, endowing the hydrogel with high conductivity (0.3 S/m). The CHs exhibited remarkable mechanical properties after the chelation of CS by Fe3+ and the formation of composites with the PPy nanorods (fracture energy 12 000 J m–2 and compression modulus 136.3 MPa). The use of a biopolymer molecular template to induce the formation of PPy nanostructures is an efficient strategy to achieve conductive multifunctional hydrogels.

Converting ubiquitous environmental energy into electric power holds tremendous social and financial interests. Traditional energy harvesters and converters are limited by the specific materials and complex configuration of devices. Herein, it is presented that electric power can be directly produced from pristine graphene oxide (GO) without any pretreatment or additives once encountering the water vapor, which will generate an open-circuit-voltage of up to 0.4-0.7 V and a short-circuit-current-density of 2-25 µA cm on a single piece of GO film. This phenomenon results from the directional movement of charged hydrogen ions through the GO film. The present work demonstrates and provides an extremely simple method for electric energy generation, which offers more applications of graphene-based materials in green energy converting field.