Preparation And Characterization Of Self-Assembled Starch Nanomicelles

In this thesis, amphiphilic starch derivatives that prepared by introducing the hydrophobic group to starch molecule chain through chemical modification were studied. The amphiphilic starch derivatives can self-assemble into nano-sized starch micelles with core/shell structure in aqueous, the hydrophobicity groups forming core of micelles by aggregation, and hydrophilic groups wrapping around the core. So, the core of nano-micelle can be used as a carrier for hydrophobic drugs, and has a great potential application in drug delivery systems.In order to select the appropriate amphiphilic starch derivatives which prepare the starch nanoparticles. The morphology of starch nanoparticles after self-assembling with different crystal types of starch(A type: corn starch, B type: potato starch, C type: pea starch), different esterification agent(lauroyl chloride, octenyl succinic anhydride), different reactions system(aqueous phase, dimethylsulfoxide, pyridine) were investigated by scanning electron microscopy(SEM). These result showed that the degree of hydrophobic modification was an important factor affecting starch derivatives amphiphilic self-assembly, and octenyl succinic anhydride starch(OSA-Starch) has a good spherical structure after assembling.Lower molecular weight of waxy maize could be produced by a certain acid hydrolysis, and then proceeded an esterification reaction in a pyridine solution, prepared in a series of different degrees of substitution of OSA-Starch. In aqueous solution form starch nano-micelles by initial water dialysis method. We studied the degree of substitution, the initial volume of water, OSA-Starch concentration effect on the particle size of the starch micelles, these results show that OSA-Starch self-assembled into nano-micelles with high degree of substitution(DS≥0.67), and the hydrophobic core becomes more closely with the DS continue to increase, resulted in the smaller the particle size of the micelles; with initial volume of water increased, produced lower rate of dialysis, smaller starch micelles could be formed; with OSA-Starch concentration increased, the solution has a greater viscosity and easy aggregation, resulted in larger particle size.The structural of characterization of amphiphilic starch derivatives were investigated by infrared spectroscopy(FTIR), FTIR results showed that the octenyl succinic group successfully introduced into starch molecules; and nuclear magnetic resonance(1H NMR) technique was used to determine the DS of OSA-Starch. The morphology of starch nano-micelles, particle size, the critical micelle concentration(CMC) were analyzed by scanning electron microscopy(SEM), dynamic light scattering(DLS), fluorescence spectrophotometer technology. SEM results show that micelles had spherical structure; DLS data indicated that the size of the micelles at 50~200nm, and had a good dispersion in solution; fluorescence spectrophotometer was used to determine the CMC of OSA-Starch in aqueous, CMC decreased with the increasing of DS.Starch nano-micelles as a carrier of hydrophobic drugs rutin. We studied the drug encapsulate properties by change DS, rutin volume, initial water volume. The results showed that with increasing degree of substitution of starch micelles, drug loading and encapsulation efficiency gradually decreased, and the micelles particle size became smaller; rutin content increased, resulted in drug loading increased, however, encapsulation efficiency and the micelles particle size decreased; with the increase of the initial volume of water, starch micelles drug loading and encapsulation efficiency decreased, the particle size became smaller.