| Summary: | 博士 === 義守大學 === 電機工程學系 === 103 === Silver nanoparticles (AgNPs) have been widely applied in various fields including nanotechnology, biotechnology, and medical industry. In order to reduce the AgNPs potential toxicity for human body, various synthesis strategies have been developed in recent years. The stability and distribution characteristics of the synthesized AgNPs are two crucial parameters in synthetic techniques. In our study, we established two synthetic systems to fabricate AgNPs-embedded chitosan particles with different size scales. In the first system, a novel approach for the one-step synthesis of AgNPs-embedded chitosan particles was proposed by using the pump-driven syringe method. The method was planned to simultaneously obtain and stabilize AgNPs in chitosan polymer matrix in situ, and the product was called silver nanoparticles-chitosan composite particles (Ag@chitosan). The diameters of the synthesized Ag@chitosan spheres ranged from 1.7 to 2.5 mm, and those of embedded AgNPs were measured to be 15±3.3 nm. Furthermore, we utilized various instruments to analyze the characteristics of the prepared Ag@chitosan spheres including the ultraviolet-visible absorbance spectrophotometer (UV-Vis), Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), energy dispersive spectroscopy (EDS), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results showed that the AgNPs were homogeneously distributed over the chitosan sphere, and these synthesized spheres possessed porous structure that could be utilized in multiple fields. Then, the antifungal effect of the Ag@chitosan spheres was evaluated, and it was found that they could inhibit the growth of Cordyceps militaris (Cm) but not Antrodia cinnamomea (Ac). Ac is an important cash crop with highly economic value in Taiwan, and our products might be an option to become a beneficial additive for cultivating Ac by inhibiting other fungi and bacteria. In the second system, we developed the microfluidic chip device made by Polymethyl methacrylate (PMMA) to synthesize the Ag@chitosan spheres with micrometer scale. The diameters of the Ag@chitosan spheres synthesized by the microfluidic method ranged from 262 to 558 μm, and their sizes could be controlled by altering the concentration of chitosan, concentration of NaOH, flow rate of continuous phase, and flow rate of dispersed phase. Moreover, we utilized various instruments to analyze the characteristics of the prepared Ag@chitosan spheres including the UV-Vis spectrophotometer, FTIR spectrometer, EDS, and SEM. The results showed that the AgNPs were also homogeneously distributed and the sphere structure was also porous as expected. In order to assess the possible toxicity of Ag@chitosan for human cells, we executed the MTT assay on both NIH-3T3 and MCF-7 cell lines. The results demonstrated that there was no observable toxicity even if the concentration of Ag@chitosan up to 1000μg/mL. Furthermore, the antibacterial effect of Ag@chitosan was evaluated by using Escherichia coli (E. Coli) broths, and the results showed that E. Coli growth could be inhibited by Ag@chitosan with dose-dependent relationship. Generally speaking, we have established two novel systems to synthesize homogeneous and stable AgNPs embedded in the chitosan particles successfully, and have confirmed the product to be highly biocompatible, non-toxic, antibacterial, and antifungal. Our synthetic systems and the synthesized products will provide a novel option of the antimicrobial research, and may be utilized in medicine and other fields in the future.
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