Facile Preparation of the ZnSe/Ag2Se Binary Heterojunction for Photocatalytic Antibacterial Efficiency

Nanofibrous membrane/self-healing hydrogel double-layer nanocomposite dressings based on oxidized dextran and carboxymethyl chitosan loading ZIF-nanozyme for enhanced bacterial-infected diabetic wound healing

Treatment of diabetic wounds at different stages remains a pressing challenge. By simulating the complex structure of natural skin, a multifunctional nanofibrous membrane/self-healing hydrogel double-layer nanocomposite dressing loading nanozyme was prepared to accelerate diabetic wound healing. The upper layer was prepared from a modified self-synthesized polyurethane (APU) nanofibrous membrane, and the bottom layer was made of an injectable self-healing hydrogel loaded with nanozyme based on oxidized dextran (ODex) and carboxymethyl chitosan (CMC). The APU nanofibrous membrane on the top can maintain a breathable and sterile environment, support the dressing, and promote cell proliferation and migration. Glucose oxidase (GOx) and l -arginine (L-Arg) at the bottom were co-doped with zinc-ZIF nanoparticles (GLZ) and acted as nanozymes for enzyme catalysis. Under the catalytic action of GOx, the high blood sugar in the wound was consumed, the pH of the microenvironment was reduced, and Zn2+ was released, achieving an effective antibacterial effect. L-Arg was catalyzed by H2O2 to generate NO in a lower pH environment, accelerating angiogenesis. Overall, the double-layer composite dressings loaded with ZIF-nanozyme exhibited comprehensive blood sugar regulation capabilities and antibacterial activity, which could promote angiogenesis and cell proliferation, and effectively treat chronic diabetic wounds.

Prohibiting the electron-phonon coupling effect in tungsten trioxide nanosheet colloid with enhanced photocatalytic antibacterial capacity

The serious combination of abundant electrons/holes in bulk primarily hinders the efficiency in the photocatalytic reaction. It is crucial to control the spatial charge dynamics through delicately designing the crystal configuration of photocatalyst. In this work, a modified tungsten trioxide nanosheet colloid (M-WO3) was synthesized by an ion exchange method. Compared to pristine WO3 (P-WO3), the crystal lattice vibration frequency of M-WO3 increases from 2.8 meV to 4.3 meV, which effectively prohibits electron-phonon coupling and powerfully accelerates the separation and transfer of photoinduced charge carriers. Irradiated by visible-light, M-WO3 shows much higher photocatalytic bacterial inactivation performance than P-WO3. In addition, this regulation method increases the surface charges of the WO3 colloid to improve its stability, which endows this colloid photocatalyst with broad prospects in practical photocatalytic antibacterial applications. This work offers guidance to construct efficiently separated photoinduced electron/hole pairs of the colloid photocatalyst by designing its crystal structure.

Decoupled electron-phonon transport in Ag2Se thermoelectric materials through constructing TiO2/MoS2 co-decorated cell-membrane-mimic grain boundaries

Ag2Se has emerged as a promising n-type thermoelectric material; however, its application is limited mainly due to the strongly coupled charge carrier and phonon transport. Enhancing phonon scattering by constructing interfacial complexes often results in low carrier mobility due to its strong carrier scattering resulting from the high energy barrier at the multiphase interface. Inspired by the cell membrane with selective permeability, we construct bio-mimic grain boundaries with TiO2 and MoS2 co-decoration in Ag2Se to decouple electron scattering from strong phonon scattering. The nanostructured TiO2 with a high dielectric constant screens the interfacial Coulomb potential, ensuring efficient carrier transport and reducing the grain boundary barriers, while the few-layer MoS2 provides significant phonon scattering to further reduce the thermal conductivity. This method effectively enhances the zT value of Ag2Se by as much as 60% and also can significantly enhance the theoretical output performance of the thermoelectric device, which highlights the effectiveness of the bio-mimic grain boundary engineering strategy.

Rough Ag2S@H-CeO2 photonic nanocomposites for effective eradication of drug-resistant bacteria and improved healing of infected cutaneous wounds

With the continuous increasing threat of drug-resistant bacteria induced cutaneous wound infections, there is a growing demand for novel effective antibiotics-alternative antibacterial strategies for clinical anti-infective therapy. Here, we report the fabrication and antibacterial efficacy of Ag2S@H-CeO2 photonic nanocomposites with rough surface through in-situ growth of Ag2S nanoparticles on CeO2 hollow spheres. With excellent photothermal property and peroxidase-like activity, as well as increased bacterial adhesion, the photonic nanocomposites demonstrated a broad-spectrum synergistic antibacterial effect against Gram-positive, Gram-positive bacteria and fungi as well biofilm in vitro. Significantly, the nanocomposites can effectively eradicate drug-resistant bacteria such as Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL E. coli). Notably, in vivo assessments validated its synergistic therapeutic potential in the treatment of MRSA-infected cutaneous wounds, all while maintaining excellent biosafety and biocompatibility. Our study offers a competitive and promising strategy for the development of a multifunctional synergistic antibacterial platform poised to effectively treat drug-resistant bacteria-infected cutaneous wounds.

Photocatalytic antibacterial agents based on inorganic semiconductor nanomaterials: a review

Microbial contamination and antibiotic pollution have threatened public health and it is important to develop a rapid and safe sterilization strategy. Among various disinfection strategies, photocatalytic antibacterial methods have drawn increasing attention due to their efficient disinfection performances and environment-friendly properties. Although there are some reviews about bacterial disinfection, specific reviews on photocatalysis focused on inorganic semiconductor nanomaterials are rarely reported. Herein, we present a systematic summary of recent disinfection developments based on inorganic nanomaterials (including metal oxides, sulfides, phosphides, carbon materials, and corresponding heterostructures) over the past five years. Moreover, key factors and challenges for inorganic nanomaterial-based photocatalytic disinfection are outlined, which holds great potential for future photocatalytic antibacterial applications.