ROS-generating injectable hydrogels via dual enzyme-triggered reaction for wound infection treatment

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Event Abstract Back to Event ROS-generating injectable hydrogels via dual enzyme-triggered reaction for wound infection treatment Yunki Lee1, Kyung-Hoon Choi2, Bong Joo Park2 and Ki Dong Park1 1 Ajou University, Department of Molecular Science and Technology, Korea 2 Kwangwoon University, Plasma Bioscience Research Center and Department of Electrical and Biological Physics, Korea Introduction: Previsouly, We reported horseradish peroxidase (HRP)-catalyzed and bioactive agents-loaded in situ forming hydrogels as a therapeutic carrier for biomedical applications[1]. It was demonstrated that moist environments and local delivery of therpeutic agents effectively promote the tissue regeneration. However, protection abilities from bacterial infections still remain a challenge for enhanced wound healing, because the infection prolong or impair optimal wound-healing process[2]. H2O2 plays a pivotal role in a wide range of phathological and biological processes, including aging, signaling, immune reactions, cancer development, and wound healing. Therefore, we hyphothesized that generation of continous oxidative stress (H2O2) could contribute to anti-infection and wound healing. In this study, H2O2-generating injectable hydrogels via dual enzyme-triggered reaction were developed for the anti-bacterial activity. The hydrogels were prepared using the HRP-catalyzed cross-linking for in situ hydrogel formation. Simultaneously, the glucose oxidase (GOx) and glucose (Glu) were also incorporated in hydrogel matrix to provide constant generation of H2O2. The physico-chemical properties of HRP/GOx-hydrogels were characterized, and the H2O2 release behaviors from gel matrices were monitored. Thereafter, the antibacterial performances of hydrogels were systematically investigated with various types of microorganisms. Materials & Methods: The HRP-reactive gelatin polymer (GH) was synthesized by conjugating 3-(4-hydroxyphenyl) propionic acid to gelatin backbone using EDC/NHS chemistry.[1] The GH hydrogels releasing H2O2 were prepared by simply mixing two GH solutions, each containing HRP/GOx and H2O2/Glu as illustrated in Fig. 1. The gelation kinetics and elastic moduli were investigated with the different Glu concentrations. In addition, the release kientics of H2O2 generated in hydrogels were monitered using a quantitative peroxide assay. We finally investigated the actibacterial activities of hydrogels against various types of microorganisms including Gram-negative and Gram-positive bacteria as well as drug resistance bacteria. Fig. 1 Schematic representation of in situ forming antimicrobial hydrogels via HRP- and GOx-mediated reaction Results & Discussion: The HRP/GOx-mediated GH hydrogels were successfully formed within 30 sec, and the mechanical strength (1-6.5 kPa) of the hydrogels could be well controlled denpending on the H2O2 and Glu concentrations. The supplement of GOx/Glu in HRP-hydrogels resulted in continuous and broad range of H2O2 release behavior for 6 h (Fig 2a). It was demonstrated that the production of H2O2 is tunable over Glu concentration, allowing them to act as dependent adjustment parameter to produce the desired dose. As shown in Fig. 2b, HRP-hydrogels had selective growth inhibition activities against only Gram-positive bacteria, according to the residual H2O2 content in hydrogels. In contrast, the HRP/GOx-hydrogels containing higher amount of H2O2 showed increased efficacy of antimicrobial activities toward both Gram-negative and Gram-positive bacteria including drug-resistant bacteria. Fig 2. Cumulative H2O2 release kinetics (a) and properties for bacterial growth inhibition (b) of HRP- and HRP/GOx-hydrogels Conclusions: We developed H2O2-generating injectable hydrogels via HRP- and GOx-catalyzed reactions for anti-infection. The physico-chemical properties of the hydrogels could be controlled by varying the concentration of HRP, GOx, and Glu. Furthermore, this system can be dynamically tuned to provide constant generation of H2O2 at a desired amount. The obtained results demonstrate that the in situ forming and H2O2-generating hydrogels have a great potential for various biomedical applications. Basic Science Research Program (NRF-2015R1A2A1A14027221)