Research On The Synthesis Of Amorphous Calcium Carbonate Composite Nanoparticles And Their Application In Drug Sustained Release And Food Preservation

With the development of nanotechnology,some nanomaterials are widely used in biomedicine and food preservation.Amorphous calcium carbonate(ACC),as a typical amorphous phase of calcium carbonate,not only has excellent biocompatibility and biodegradability,but also has the sensitivity to acidic p H,thus its has been studied widely for use in biomaterial applicaiotns.Compared with crystalline calcium carbonate,ACC nanoparticles have a high potential for application in the field of nanomaterials due to their smaller scale,easy modification properties.However,their applications in biomaterial are also limited by the poor stability and acid resistance.Therefore,how to effectively utilize or solve these defects of ACC is the key to further apply in biological fields.In this paper,we focus mainly on the designing and synthesizing stable composite nanomaterials based on ACC and exploring their biological applications.The main research contents and results are as follows:(1)ACC nanoparticles with average particle size less than 100 nm were synthesized in alcohol solution by "vapor diffusion method".Then,phosphate-stabilized amorphous nanoparticles(ACCP)were successfully prepared in aqueous solution by "coprecipitation method".The characteristics of nanoparticles were studied by analysis of the synthesis conditions.By analyzing the phase transition of products at room temperature,it can be seen that ACCP nanoparticles can maintain their amorphous structure for more than 60 days and have good storage stability.Meanwhile,a series of inorganic nanocarriers,namely ACC and ACCP coated curcumin(Cur)nanomaterials,were successfully constructed by adding hydrophobic drugs in reaction process.We have investigated the drug release properties of ACC-Cur and ACCP-Cur based on the degradability in physiological environments.The results showed that in the same p H environment,the rate of drug release of ACC was slightly faster than ACCP,and the cumulative release rate after 40 h was more than 50%.The carriers were highly lethal to lung cancer cells(A549),and the cell survival rate was lower than 50% when the carrier concentration was 32 μg/m L.Based on Cur excellent antioxidant properties,we also analyzed the free radicals scavenging ability of ACC-Cur and ACCP-Cur and the protective effect of Cur.The results showed that nanoparticles can not only assist in scavenging free radicals,but also hinder the decomposition of Cur,effectively expanding the application range of nanoparticles;(2)To achieve a special design of release properties of ACCP nanoparticles,Alginate/ACCP composite nanoparticles were developed.The resultants not only have a particle size of less than 200 nm,but also form a uniform dispersion after ultrasonic treatment.Based on the p H-sensitive property of alginate,we have investigated the drug release properties of nanoparticles and tested the effect of carriers on the growth of A549 cancer cells.The results showed that the release rate of composite nanoparticles gradually decreased with the increase of alginate under the same release medium.When the amount of alginate was 1.0 mg/m L,the cumulative release rate of nanoparticles at 40 h was lower than 40%.In addition,the composite nanoparticles showed excellent cancer cell killing ability and showed concentration-dependent growth,but the control carriers had little effect on the cells,and the toxicity belonged to grade 1.Hence,through rational optimal design,we can synthesize composite nanoparticles with excellent sustained-release properties and use them to provide new strategies for long-term treatment of cancer;(3)With natural polymer material chitosan(CS)as film matrix and glycerol as plasticizer,a series of CS/ACCP and CS/Alginate/ACCP composite fresh-keeping films were prepared by fluidization.Meanwhile,the effect of memebrane physical-chemical properties from ACCP and Alginate/ACCP mass were investigated.The results showed that nanoparticles can significantly improve the tensile strength and elongation at break of chitosan film and improve its barrier performance to water vapor.When the addition amount is 8%,the elongation at break reaches maximum value,and comprehensive performance is better.Furthermore,Cur release properties of chitosan films were also studied,and antioxidant,antibacterial and preservation effects were explored.The results showed that chitosan films had good bacteriostatic and preservation properties.Based on composite nanoparticles,biofilm materials with greater value in biological fields can be prepared by further optimal design.