Hydrogels prepared by PEG-catechol group modified polypeptides for antimicrobial and drug delivery applications

Abstract

Recently there is an increasing interest in biomimetic hydrogels with impregnated antimicrobial nanoparticles and antibiotics which possess good biocompatibility high degradability and low toxicity as well as good antibacterial activity against various bacteria The biomimetic hydrogels would potentially be promising for biomedical applications such as wound healing tissue engineering and payload delivery systems In this study we designed a type of hydrogels based on PEG-catechol group modified gelatin and in situ formation of antimicrobial nanoparticles (Ag NPs) for antimicrobial application as well as encapsulation of a drug (DOX-anticancer agent) for drug delivery The Ag NP-loaded gelatin-PEG-catechol hydrogels were formed through in situ formations of Ag NPs in the polypeptide solutions followed by an enzymatic cross-linked reaction between HRP enzyme and oxidizing agent H2O2 The experimental results showed that the antimicrobial Ag NPs could be formed in the polypeptide solutions without adding toxic reducing agents and/or additional processes such as UV or thermal treatment The results also showed that the gelation time mechanical strength adhesive strength swelling ratio and enzymatic degradation behavior of hydrogels can be tuned by varying enzyme/oxidative agent concentration catechol content and redox reaction conditions including redox reaction time and initial Ag+ ion concentration In particular the Ag NP-loaded gelatin-PEG-catechol hydrogels exhibited excellent antibacterial activities against both gram-negative and positive bacteria For the injectable DOX-encapsulated hydrogels the hydrogels could be simply formed via coordinated/oxidized cross-linking by Fe3+ ions and H2O2 with short gelation time It was found that the DOX was loaded onto the hydrogel network by metal-DOX/catechol complexes The mechanical strength swelling ratio and degradability behavior could be controlled by varying Fe3+/H2O2 concentration It was found that the DOX release can be controlled by varying the solution pH

Date of Award	2020
Original language	English
Supervisor	Jeng-Shiung Jan (Supervisor)