Thesis (M.Sc.)--Chulalongkorn University, 2008

Silk sericin microparticles are obtained from precipitation of sericin solution in organic solvent (methanol, ethanol and iso-propanol) which develops a novel technique for preparation silk sericin microparticles in mass scale. The solution was prepared from boiling solution of silk fiber with degumming agent (distilled water, sodium hydrogen carbonate, and citric acid). Effects of organic solvent on the molecular characteristics of silk sericin microparticles were investigated by Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) spectroscopy. The results of ATR FT-IR spectra elucidated that the conformation of the silk sericin microparticles were changed from random coil to β-sheet after treatment. The appearance of β-sheet conformation may be associated with the packing of molecular chains. The secondary structure of silk sericin microparticles treated in methanol had more β-sheet structure than that treated in iso-propanol. The results indicated that the secondary structure of silk sericin microparticles could be controlled by organic solvent from the preparation. The morphology of silk sericin microparticles was observed by scanning electron microscope. The average particle size of silk sericin microparticles were about 5 μm but it does not completely isolate arising from its native structure. Silk sericin microparticles can apply for silver nanoparticles deposition. Silver nanoparticles are very well dispersed and deposited on silk sericin microparticles.