Preparation And Applied Basic Research Of Starch Nanoparticles Based On Dry-hot Acid Hydrolysis

Starch is the second largest biomass resource after cellulose,and it is a bio-based material with good biocompatibility and safety.Starch nanoparticles are one of the starch derivatives.They have the inherent safety properties of starch,and also have the scale effect brought by nanometer size,which has a good application prospect in drug delivery systems.Nanoprecipitation is one of the methods for preparing starch nanoparticles,which is characterized by fast,simple and reproducible.However,the efficiency of the traditional nanoprecipitation method is not high,which affects the widespread promotion of this method.In this paper,the research on the preparation of starch nanoparticles by dry heat acid hydrolysis combined with nanoprecipitation was carried out,and the characteristics and application basic research of starch nanoparticles were explored.1.Starch was pretreated and modified based on dry-hot acid hydrolysis,and starch nanoparticles were prepared by combined nanoprecipitation.The effects of solid acid hydrolysis process and nano-precipitation process on the properties of starch nanoparticles were investigated.And the morphology,crystal structure and thermal stability of the starch nanoparticles prepared were investigated.Combined with the literature and experimental research,the preparation mechanism was initially discussed.The starch nanoparticles were prepared by dry-hot acid hydrolysis combined with nanoprecipitation.The effects of dry-hot acid hydrolysis and nanoprecipitation on the particle size and particle size distribution of starch nanoparticles were discussed.Starch nanoparticles prepared under optimal conditions(Optimum conditions: dry-hot acid hydrolysis reaction at 80 ?,hydrochloric acid concentration of 3% for 12 h,and starch nanoparticles were prepared by nanoprecipitation with 50 mg/mL starch solution and ethanol content of 400%)could be obtained with particles size of 200 nm and the PDI(Polymer dispersity index)of 0.3.Moreover,dry-hot acid hydrolysis had an effect on the properties of starch nanoparticles.It was found that the dry-hot acid hydrolysis method made the starch granules loose and easy to break,which made starch treated by dry-hot acid hydrolysis soluble in hot water.Ethanol and acetone had little effect on the properties of starch nanoparticles according to characterization of different nanoparticles,but the nano-starch prepared by acetone was unstable,and some particles could form a cavity structure,which was also proved by experiments and reasonablely inferred.2.Starch nanoparticles were used as templates for template polymerization to synthesize composite nanoparticles of starch and PAA(Polyacrylic acid),and then PAA nanocapsule(200-300 nm)was obtained by removing the template,and the corresponding mechanism of synthesis of nanocapsule was explored.Acrylic acid was adsorbed on the surface of the starch nanoparticles by hydrogen bonding,and polymerized to form composite nanoparticles,and the PAA nanocapsules were obtained after removing the starch template.Thus,starch nanoparticles became a green template for the preparation of nanocapsules.3.The drug loading and dissolution properties of the starch nanoparticles were evaluated.The results showed that the loading rates of starch nanoparticles on aspirin and asarone brain were 31.73 4.83% and 25.66 5.63%,respectively,and the release of aspirin-loaded nanoparticles could be completed within 36 h.Compared with the release of aspirin tablets,starch nanoparticles had a sustained release effect.Besides,the initial release rate of asarone-loaded particles was faster than that of the original drug,but with the drug release,the release rate of asarone-loaded particles was lower than that of the original drug.The release of aspirin-loaded granules and asarone-loaded granules was consistent with the two-phase kinetic model and the first-order kinetic model.