科研之友
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摘要
We designed a hydrogel with durable and excellent antibacterial activity. Amphiphilic block copolymer, polycaprolactone-block-poly(glutamic acid) (PCL-b-PGA), was first synthesized by ring-opening polymerization with amine-terminated polycaprolactone (PCL-NH2 ) as the macro-initiator and Bz-Glu-NCA as the monomer. This copolymer self-assembled into vesicles in solvent mixture of DMF/water with a critical vesiculation concentration of 5.27 mu g mL(-1). Antibacterial Ag-decorated vesicles were then prepared by in situ deposition of silver nanoparticles in PGA coronas of the vesicles as a result of the electrostatic interaction between carboxyl groups and Ag+ H-1-NMR analysis revealed the composition of PCL47-b-PGA(46) block copolymer. Dynamic light scattering (DLS) study revealed an intensity-averaged diameter of 215 nm for the vesicles with a polydispersity of 0.029. Transmission electron microscopy (TEM) confirmed a hollow structure of the vesicles with a number-averaged diameter of 270 nm, and the presence of sliver nanoparticles on the vesicles. Atomic force microscopy (AFM) revealed the collapsed surface morphology of vesicles with a width to height ratio of 18, confirming further the hollow structure of the vesicles. Meanwhile, Ag-decorated vesicles were incoporated into Pluronic F127 hydrogels to afford antibacterial hydrogels, showing good degradability at different pH. MIC90 (minimum concentration of inhibiting 90% of bacterium) of the antibacterial vesicles was 10 mu g mL(-1) against Gram-negative bacterium E. coli, and it was 20 mu g mL(-1) against Gram-positive bacterium S. aureus, and measured by spread plate method, which afford the hydrogels excellent antibacterial property. Oxford cup tests confirmed that MIC50 of the antibacterial hydrogel against both E. coli and S. aureus is 7.5 mu g mL(-1) and MBC (minimum bactericidal concentration) against both of them is 30 mu g mL(-1). The in vitro degradation tests confirmed that the vesicle was degraded in the presence of lipase. Overall, we provide a new method for preparation of antibacterial hydrogels, which may have promising biomedical applications requiring a long-acting antibacterial therapy such as inflammation triggered by bacteria infection, wound healing after surgery and sterilization for the implant devices, etc.
- 出版日期2018-1
- 单位同济大学
