酶触发聚合物囊泡-核交联胶束转变用于响应性抗菌剂释放

通过使用药物运载体系来提高抗菌物质的使用效率是应对抗生素耐药性的有效途径.本文报道了一种制备细菌酶响应聚合物囊泡作为"智能型"抗菌剂载体的方法.通过可逆加成-断裂链转移聚合(RAFT)制备的脂酶和硝基还原酶响应的二嵌段共聚物PEG-b-PA和PEG-b-PN,能够在水溶液中自组装形成聚合物囊泡组装体.该囊泡组装体在没有酶存在的条件下相对稳定,而在脂酶或硝基还原酶的作用下发生从囊泡到核交联胶束的形貌转变.基于这一转变过程实现了负载在囊泡中的抗菌剂(三氯生,抗菌肽Parasin Ⅰ和溶菌酶)的选择性释放,并研究了针对大肠杆菌(E.coli,革兰氏阴性菌)、金黄色葡萄球菌(S.aureus,革兰氏阳性菌)和白色念珠菌(C.albicans,真菌)的生长抑制效果.

Enzyme-triggered Transition from Polymeric Vesicles to Core Cross-linked Micelles for Selective Release of Antimicrobial Agents

The optimization of the efficacy of currently available antibiotics by taking advantage of drug delivery systems has emerged as an alternative methodology to combat the severe threat of antimicrobial resistance,which can in part bypass the challenges for developing brand new antimicrobial agents.Herein,we report a new strategy to design and fabricate bacterial enzyme-responsive polymersomes as "smart" antimicrobial delivery carriers.Lipase (Lip)-and nitroreductase (NTR)-responsive amphiphilic block copolymers (BCPs),poly(ethylene glycol)-b-poly(2-((((4-acetoxybenzyl)oxy)carbonyl)amino)ethyl methacrylate) (PEG-b-PA) and poly(ethylene glycol)-b-poly(2-((((4-nitrobenzyl)oxy)carbonyl)amino)ethyl methacrylate) (PEG-b-PN),consisting of enzyme-reactive pendent chains,were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization.The resultant BCPs self-assembled into vesicles with hydrophilic PEG coronas and hydrophobic enzyme-reactive bilayers.The as-assembled vesicles were relatively stable in aqueous solution but they underwent enzymatic degradation with the formation of core cross-linked (CCL) micelles through aminolysis reaction from decaged carbamate linkages.Several antimicrobial agents,including hydrophobic triclosan (TCN),hydrophilic antibacterial peptide (Parasin Ⅰ),and therapeutic protein lysozyme (Lyz),were encapsulated into the enzymeresponsive polymersomes either within the aqueous interiors or hydrophobic bilayer membranes.We demonstrated that the enhanced release of encapsulated antibacterial agents as well as antimicribial activities against Gram-negative (E.coli),Gram-positive (S.aureus) bacteria,and fungi (C.albicans),could be achieved when triggered by Lip or NTR.