Lysine aggregates-based nanostructured antimicrobial peptides for cariogenic biofilm microenvironment-activated caries treatment

Dental caries is one of the most prevalent and costly biofilm-induced oral diseases that causes the deterioration of the mineralized tooth tissue.Traditional antimicro-bial agents like antibiotics and antimicrobial peptides(AMPs)struggle to effectively eradicate bacteria in biofilms without eliciting resistance.Herein,we demonstrate the construction of FeOOH@Fe-Lysine@Au nanostructured AMPs(nAMPs)dis-tinguished by their AMP-like antibacterial activity and self-producing reactive oxygen species(ROS)capacity for caries treatment.On the one hand,FeOOH@Fe-Lysine@Au nAMPs can catalyze glucose oxidation to generate ROS within the cariogenic biofilm microenvironment,resulting in the disintegration of the extra-cellular polymeric substance matrix and the exposure of bacteria.On the other hand,FeOOH@Fe-Lysine@Au nAMPs can attach to bacterial surfaces via electrostatic attractions,proceeding to damage membranes,disrupt metabolic pathways,and inhibit protein synthesis through the aggregated lysine and the generated ROS.Based on this antibacterial mechanism,FeOOH@Fe-Lysine@Au nAMPs can effectively eradicate Streptococcus mutans and its associated biofilm,significantly impeding the progression of dental caries.Given the straightforward and cost-efficient prepa-ration of FeOOH@Fe-Lysine@Au nAMPs compared to AMPs that require specific sequences,and their minimal adverse impacts on gingival/palatal tissues,major organs,and oral/gut microbiomes,our research may promote the development of novel therapeutic agents in dental health maintenance.

A self-regulated phototheranostic nanosystem with single wavelength-triggered energy switching and oxygen supply for multimodal synergistic therapy of bacterial biofilm infections

The exploration of antibiotic-independent phototherapy strategies for the treatment of bacterial biofilm infections has gained significant attention.However,efficient eradication of bacterial biofilms remains a challenge.Herein,a self-regulated pho-totheranostic nanosystem with single wavelength-triggered photothermal therapy(PTT)/photodynamic therapy(PDT)transformation and oxygen supply for multi-modal synergistic therapy of bacterial biofilm infections is presented.This approach combines a eutectic mixture of natural phase-change materials(PCMs)and an aggregation-induced emission(AIE)phototheranostic agent TPA-ICN to form col-loidally stable nanopartcicles(i.e.AIE@PCM NPs).The reversible solid-liquid phase transition of PCMs facilitates the adaptive regulation of the aggregation states of TPA-ICN,enabling a switch between the energy dissipation pathways for enhanced PDT in solid PCMs or enhanced PTT in liquid PCMs.Addition-ally,oxygen-carrying thermoresponsive nanoparticles are also introduced to alleviate the hypoxic microenvironment of biofilms by releasing oxygen upon heating by AIE@PCM NPs with enhanced PTT.The nanosystem exhibits outstanding therapeu-tic efficacy against bacterial biofilms both in vitro and in vivo,with an antibacterial efficiency of 99.99%.This study utilizes a self-regulated theranostic nanoplatform with adaptive PTT/PDT transformation via the phase transition of PCMs and heat-triggered oxygen release,holding great promise in the safe and efficient treatment of bacterial biofilm infections.

浅析我国农村生活污水处理的技术特点及应用现状

本文总结了我国农村污水处理常用的主流工艺,叙述了人工湿地、生物膜技术和生物滤池等几种农村生活污水处理技术的优缺点,并在此基础上,介绍了无动力-蒸发和颗粒污泥等农村污水处理新技术。本文总结了我国农村污水处理的相关技术及面临的问题,为农村污水治理提供了高能效、易管理、易运行且经济适用的技术建议。