| Summary: | 碩士 === 國立中央大學 === 生醫科學與工程學系 === 106 === Metallogels were established based on coordinative interactions, exhibiting unique abilities, and being applied for various biomedical applications. However, the applications of metallogels for wound healing property has not been explored. In this study, we report a newly nature-derived metallogels developed by coordination of polyphenols and metal ions. Gelation occurs by mixing low-cost polyphenolic tannic acid (TA) and group (IV) metal ions (titanium ions) to form TA-TiIV gel. The TA-TiIV gel exhibits a good ability to incorporate diverse functional metal ions by in situ co-gelations. Herein, we used five metal ions: ferric ions (Fe3+), copper(II) ions (Cu2+), zinc(II) ions (Zn2+), cobalt(II) ions (Co2+) and nickel(II) ions (Ni2+) for antimicrobial tests. The formations and collapse of formed metallogels are sensitive to external pH – and the presence of H2O2, which displays in the healing process of infected wounds. The chemical and coordinative structures of TA-TiIV metallogel were characterized by UV-Vis spectrometer and Fourier-transform infrared (FT-IR) spectroscopy. The release of metal ions was evaluated by inductively coupled plasma mass spectrometry (ICP-MS), indicating the different releasing profiles upon the types of metal ions. For TA-TiIV-CuII metallogel, distinct releasing rates at different pH values of 5.5, 7.4 and 8.4 has been studied. The result indicates the pH-dependent metal ions release manner. Moreover, the bacterial environment has been investigated by UV-Vis spectrometer and pH meter, the result showed the acidic environment during the metabolism process of bacteria. Besides, HRP incorporated with TA-TiIV-CuII HG brought to a significant Cu2+ ions released, where H2O2 is presented. As the results, antibacterial effect of synthesized metallogels againsts Gram-negative Escherichia coli, and Gram-positive Methicillin-Resistant Staphylococcus aureus (USA300), Staphylococcus epidermidis bacteria has been investigated by agar diffusion test. Simultaneously, cytotoxicity of metallogels on NIH 3T3 fibroblast cell line was also explored by MTT assay, and turned out to be excellent biocompatibility. For clinical applications as infected wound dressings, TA-TiIV-CuII HG indicated the antimicrobial effect, led to significant smaller in wound area after 8 days, compared to TA-TiIV HG and Gauze. Consequently, demonstrated HG is promising a potential materials for infected wound applications.
Keywords- Metallogels, tannic acid (TA), metal ions, nature-derived
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