Preparation And Properties Of Amylose Nanoparticles

As a kind of natural polymer, starch is renewable, inexpensive, biodegradable andnon-toxicity. Starch has many functional groups which can be modified by chemicalmethod to meet different needs. Starch nanoparticles have many advantages, such as smallsize, large surface area, biocompatibility and non-toxic, therefore, starch nanoparticlescould be used as drug carriers, adsorbents and embedding agents.In this study, amylose was dissolved in solutions of DMSO/H2O with differentvolume proportions. Starch nanoparticles were prepared by using ethanol as the precipitant.The influence of temperature, proportion of DMSO/H2O, decentralized manner during theprecipitating, the dosage of ethanol concentration of starch suspension on the morphologyand particle size of starch nanoparticles were investigated. Then the particle size and theparticle size distribution of starch nanoparticles obtained at various conditions in watermedium were investigated. Two surfactants, Tween80and Span80, were selected to studythe influence of surfactant on the morphology and particle size of starch nanoparticles.The effects of storage time, temperature, relative humidity and surfactant on thecrystallization property of starch nanoparticles were also studied. The aim of this study wasto explore approach to prepare starch nanoparticles with suitable size, morphology andproperty through controlling preparaing conditions, using surfacants and adjusting storageconditions.SEM was used to observe the morphology and particle size of starch nanoparticles,the results showed that when the proportion of DMSO/H2O was90/10the preparednanoparticles were smaller than that of100/0. When the proportion of DMSO/H2O was60/40, the obtained particles were very large and non-uniform, the system had anagglomeration. The decentralized manner during the precipitating had an important effecton size and morphology of the particles. The ultrasonic shock method had a betterdispersion effect than magnetic stirring. The results also showed that the particle size of amylose nanoparticles decreased as increasing of the dosage of ethanol. The particle sizeand particle size distribution of the nanoparticles dispersed in water medium wereexamined by using DLS, the results were consistent with the conclusion of the SEM test.To study the effects of surfactants, Tween80and Span80, on the size and morphologyof starch nanoparticles, SEM and DLS were used to characterize the amylosenanaoparticles prepared by adding surfacants. The results showed that the particle size ofamylose nanoparticles increased as increasing of the concentration of surfactant from0.5%to4.0%. The smallest nanoparticles were obtained when using the mixture of thesurfactants with HLB of12.325.XRD analysis was used to characterize the influence of storage conditions andsurfactant on crystallinity of the amylose nanoparticles. The results showed that thehumidity and water content of starch nanoparticles had significant effect on crystallinity,higher water content may hinder the recrystallization process. In addition, change of thedegree of crystallinity was related to the surfactant.