Cowberry extract loaded chitosan hydrogel with photothermal and antioxidant properties promotes infected wound healing.

Bacterial infection and oxidative stress impede clinical wound healing. Herein, the plant-derived cowberry extract (CE) was first explored as a natural photothermal agent and antioxidant to deal with bacterial infection and oxidative stress. After loading in the carboxymethyl chitosan (CMCs)/oxidized dextran (Odex) hydrogel, the photothermal effect of CE was highly enhanced by CMCs. The controlled temperature induced by CE-containing hydrogel under NIR laser irradiation could rapidly (10 min) and effectively kill Staphylococcus aureus (S. aureus, 99.3 %) and Escherichia coli (E. coli, 94.6 %). Besides, this hydrogel exhibited a fast gelation and hemostasis abilities, high stability, adhesion and ROS scavenging capabilities, as well as good injectability and biocompatibility. Above superior properties make this hydrogel to accelerate the wound healing in S. aureus-infected mice, and it is expected to be a potential clinical wound dressing.

Mild hyperthermia-assisted chitosan hydrogel with photothermal antibacterial property and CAT-like activity for infected wound healing.

Infected wounds pose a serious threat to public health and pose a significant challenge and financial burden worldwide. The treatment of infected wounds is now an urgent problem to be solved. Herein, mild hyperthermia-assisted hydrogels composed of carboxymethyl chitosan (CMCs), oxidized dextran (Odex), epigallocatechin gallate (EGCG) and PtNPs@PVP (CAT-like nanoenzymes) were proposed for the repair of infected wounds. The incorporation of PtNPs@PVP nanoenzymes give the hydrogels excellent photothermal property and CAT-like activity. When the temperature is maintained at 42-45 °C under 808 nm near infrared (NIR) exposure, the CMCs/Odex/EGCG/Nanoenzymes (COEN2) hydrogel demonstrated highly enhanced antibacterial ability (95.9 % in vivo), hydrogen peroxide (H2O2) scavenging ratio (85.1 % in vitro) and oxygen supply (20.7 mg/L in vitro). Furthermore, this mild-heat stimulation also promoted angiogenesis in the damaged skin area. Overall, this multifunctional hydrogel with antibacterial, antioxidant, oxygen supply, hemostasis, and angiogenesis capabilities has shown great promise in the repair of infected wounds. This study establishes the paradigm of enhanced infected wound healing by mild hyperthermia-assisted H2O2 scavenging, oxygen supplemental, and photothermal antibacterial hydrogels.

PEI-PLGA nanoparticles significantly enhanced the immunogenicity of IsdB137-361 proteins from Staphylococcus aureus.

INTRODUCTION: Staphylococcus aureus seriously threatens human and animal health. IsdB137-361 of the iron surface determinant B protein (IsdB) from S. aureus exhibits the strong immunogenicity, but its immunoprotective effect is still to be further promoted. Because PEI-PLGA nanoparticles are generated by PEI conjugate with PLGA to develop great potential as a novel immune adjuvant, the immunogenicity of IsdB137-361 is likely be strengthened by PEI-PLGA. METHODS: Here, PEI-PLGA nanoparticles containing IsdB137-361 proteins were prepared by optimizing the entrapment efficiency. Mice were immunized with IsdB137-361 -PEI-PLGA nanoparticles to assess their anti-S. aureus effects. The level of IFN-γ, IL-4, IL-17, and IL-10 cytokines from spleen lymphocytes in mice and generation of the antibodies against IsdB137-361 in serum was assessed by ELISA, the protective immune response was appraised by S. aureus challenge. RESULTS: IsdB137-361 proteins loaded by PEI-PLGA were able to stimulate effectively the proliferation of spleen lymphocytes and increase the secretion of IFN-γ, IL-4, IL-17, and IL-10 cytokine from spleen lymphocytes, and significantly enhance generation of the antibodies against IsdB137-361 in serum, reduce the level of bacterial load in liver, spleen and kidney, and greatly improve the survival rate of mice after challenge. CONCLUSION: These data showed that PEI-PLGA nanoparticles can significantly enhance the immunogenicity of IsdB137-361 proteins, and provide an important reference for the development of novel immune adjuvant.

ARTP mutation and adaptive laboratory evolution improve probiotic performance of Bacillus coagulans.

Bacillus coagulans is a thermophilic, facultative anaerobic, spore-forming Gram-positive bacterium, which is used as a probiotic in animal feed and human dietary supplements. In the present study, a bile-resistant thermophilic B. coagulans WT-03 strain was isolated and genetically identified. Atmospheric pressure room temperature plasma (ARTP)-induced mutation combined with adaptive laboratory evolution (ALE) was used to improve the probiotic performance of B. coagulans WT-03. After 15 s of ARTP mutation and 40 days of ALE culture, a mutant artp-aleBC15 was obtained and showed the improved tolerance to pH 2.5 and 0.3% bile salt with a survival rate of 22.4%. Further studies showed that the artp-aleBC15 mutant exhibited a relatively stable morphology, lower permeability, and higher hydrophobicity of cell membrane compared with the parent strain of B. coagulans. Additionally, artp-aleBC15 could maintain homeostasis with an intracellular pH of over 4.5 and had the altered contents of saturated fatty acids/unsaturated fatty acids in the cell membrane at pH 2.5. Our study proved that ARTP mutation combined with ALE is an efficient mutagenesis strategy to improve the probiotic performance of B. coagulans for potential industrial use.Key Points• A B. coagulans strain that can grow at 80 °C and 0.3% bile salt was screened.• ARTP combined with ALE effectively mutated B. coagulans WT-03.• B. coagulans artp-aleBC15 mutant showed an improved probiotic performance.• The mutant exhibited the lower permeability and altered fatty acid contents in the cell membrane.