The Mechanism Of Nanoparticles Stabilizing Pickering Emulsion And The Improvement Of Bioavailability Of Insoluble Drugs

Pickering emulsion can be prepared by particles based on biological macromolecules,which are non-toxic and biocompatible.It can be widely used in biomedical,food and other fields.There are many factors that affect the stability and function of Pickering emulsion,and the property of particle is one of the most important factor.However,the stability mechanism and the effect of particle shape,size and hardness on the stability of Pickering emulsion and the improvement of the bioavailability of the insoluble drugs by Pickering emulsion have not been systematically studied.In order to get Pickering emulsion with high stability and wide application,we use the nanoparticles(NPs),which are made by a-lactalbumin but have different shapes,sizes and hardness to prepare the Pickering emulsions,then research the effects of particle properties on the stability and application of Pickering emulsions,and select the best nanoparticles.The primary work of this paper are as follows:1.Construction of self-assembled nanoparticles with different shapes,sizes and hardness.The amphiphilic polypeptides were obtained by using bacillus licheniformis protease to enzymolyse a-lactoalbumin.In different experimental conditions,the amphiphilic peptides were self assembled to form nanoparticles with different sizes and morphology.Then the free amino groups on adjacent polypeptides were cross-linked via glutaraldehyde and nanoparticles with higher harderness were obtained due to the limited relative motion of the polypeptide.2.Preparation and stability comparison of different Pickering emulsions.The Pickering emulsions prepared by different NPs were characterized by camera,microscope,fluorescence confocal microscope and cryoscanning electron microscope respectively.The final consequence showed that Pickering emulsion was successfully prepared.The long-term and short-term stability analysis of Pickering emulsion prepared by different nanoparticles was conducted.Then the mechanism of the stability of Pickering emulsion was studied by measuring the adsorption capacity of nanoparticles on the oil-water interface and the strength of the interfacial film formed by nanoparticles.The final experimental results show that Pickering emulsions prepared by spherical nanoparticles with low hardness and small particle size have the best stability.3.The comparison of bioavailability of curcumin in different Pickering emulsions.Through the digestion of Pickering emulsions by simulating intestinal fluid in vitro,we found that Pickering emulsion prepared by small nanospheres or long nanotubes has the fastest digestion rate,and the emulsion prepared by large nanospheres has the slowest digestion rate.And the digestion rate of these Pickering emulsions is faster than that of individual medium-chain triglycerides.The results of Caco-2 cell endocytosis experiments indicates that emulsions with small particle size and good dispersivity is the most easily taken up by cells.Finally through the rat gastric experiment we measured the curve of the plasma concentration of curcumin embedd in emulsions with times.And the final result was similar to the in vitro digestion and cell experiments.Pickering emulsion could indeed improve the bioavailability of curcumin,especially the Pickering emulsion prepared by nanospheres with smaller particle size.To sum up,we studied the effect of the properties of nanoparticles on the stability and application of Pickering emulsionk,and provide a theoretical basis for the selection of nanoparticles in the preparation of Pickering emulsion,which is beneficial to improve the stability of Pickering emulsion and optimize its application.