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Background: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. Objectives: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O- carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. Methods: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. Results: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. Conclusions: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation. [ABSTRACT FROM AUTHOR]

Herein, a novel boron doped carbon sphere (BCS) and its derived MnO2 nanocomposite electrode (abbreviated as MnO2/BCS) are firstly prepared via a facile hydrothermal strategy, which was successfully confirmed via a combined characterization including SEM, TEM, EDS, FT-IR, Raman and XPS. Due to the introduction of BCS, the MnO2/BCS shows hierarchical nanoflower-like morphology with a smaller particle size and higher specific surface area than that of pristine MnO2. Importantly, the resultant MnO2/BCS with proper addition of BCS displays superior OER performance than those of the pristine MnO2. The electrochemical measurement results demonstrate that the optimal MnO2/BCS0.08 can give rise to a lowest overpotential mere 170 mV at 10 mA·cm-2, onset potential reaching 1.33 V together with smallest Tafel slope value of 31.43 mV dec-1, which can be mainly due to the higher conductivity, faster charge transfer kinetics and higher electrocatalytic active sites of the MnO2/BCS0.08 than those of other counterparts. Undoubtedly, the incorporation of BCS is mainly responsible for the enhanced electrocatalytic activity. Furthermore, the MnO2/BCS0.08 also has a prominent long-term stability in alkaline conditions. In conclusion, our present work demonstrates an effective strategy to enhance the OER performance of MnO2 by incorporation of the carbon nanomaterials. [ABSTRACT FROM AUTHOR]