Research On The Composite System Of Protein, Polysaccharide

Soy protein isolate (SPI) and gelatin (Gel) and hyaluronic acid (HA) are natural macromolecule, and their based materials are expected to be environment-friendly, biodegradable and reproducible products. We focused on prepare composite films based on SPI and gelatin, and novel strategies to create hyaluronic acid-silver nanoparticle composite.In the first part, the author researched the preparation of composite films SPI and Gelatin by solution film-forming method and melting film-forming method. The properties of film-forming solution were investigated. The influence of the ratio of SPI/Gel (w/w) on the mechanical properties, apparent properties, gas barrier properties and microstructure of SPI/Gel (w/w) composite films was studied. Results showed that when the ratio of SPI/Gel (w/w) was about 7/3, their compatibility was best, and tensile strength and elongation at break of the composite film were 31.59MPa and 65.96%, In addition, the composite film had better apparent film properties, gas barrier properties, and the surface of composite film presents certain hydrophobic. Meanwhile, the author researched the composite films SPI and Gelatin by melting film-forming methed which has advantages both SPI and Gelatin. Results showed that when the ratio of SPI/Gel (w/w) was about 9/1, tensile strength and elongation at break of the composite film were 41.97MPa and182.2%. When the ratio of SPI/Gel (w/w) was about 7/3, their compatibility was best. By comparing with the two methods, the composite film which was preparaed by solution film-forming method had much better gas barrier properties, and the composite film preparaed by melting film-forming methed had much better mechanical properties. The composite film preparaed by melting film-forming methed had strong water affinity.In seond part, a simple route for the synthesis of hyaluronic acid-silver nanoparticle composite using HA has been proposed in this work. Hyaluronic acid-silver nanoparticle composite was obtained by the method of UV irradiation of an aqueous solution containing silver nitrate (AgNO3) and HA in the absence of any reducing agents and protecting agents. The hyaluronic acid-silver nanoparticle composite has high stability and the nanometer silver load on HA. Transmission electronic microscopy (TEM) images and UV-Vis spectrum analysis of hyaluronic acid-silver nanoparticle composite confirmed the formation of metallic silver. The UV-Vis spectrum showed that the purified solution yielded the maximum absorbance at about 440 nm due to surface plasmon resonance of the silver nanoparticles. Infrared spectroscopy, zeta electric potential and viscosity confirmed that the formation of silver nanoparticles might be related with the reduction and photochemistry between HA and UV light. Hyaluronic acid-silver nanoparticle composite showed excellent antibacterial activity against Staphylococcus aureus.