Preparation And Properties Study Of Environmentally Responsive Drug Carriers

Nanogel is a nano-scale hydrogel with cross-linked three-dimensional network structure.Based on its high specific surface area,excellent biocompatibility and simple synthesis method,nanogel is used in biological fields such as drug delivery.It has a very wide range of applications.In addition,the nanogel raw material contains a large number of active groups for modification.According to this feature,it can be made into nanogels with different uses and different properties,such as smart nano hydrogels sensitive to different environmental stimuli.Sodium alginate was grafted using glutamic acid.The experimental procedure was optimized and improved for the purpose of saving time and raw reagents and improving reaction efficiency.The product was characterized by ninhydrin color reaction,IR and NMR.The results showed that glutamic acid was successfully grafted on the-COOH group at the C6 position of sodium alginate,and the reaction rates of Glu were obtained by ninhydrin reaction and UV spectrophotometry.The Glu-SA was modified with five amounts of ethylenediamine to obtain a pH-sensitive product,and the pH-sensitive sodium alginate was characterized by Zeta potential,and the product with best p I was selected to be the starting material for the next reaction step.Then,N-isopropyl acrylamide was used for radical polymerization to prepare a temperature-sensitive,pH-sensitive double-response nanogel with a semi-interpenetrating network structure.The nanogel products were characterized by transmission electron microscopy,scanning electron microscopy,atomic force microscopy and Zeta potential analyzer.The nanogels with good dispersion and narrow size distribution were obtained and average particle size was 451.47 nm.The nanogels were also subjected to pH-sensitive,temperature-sensitive,in vitro drug-loading and drug-releasing experiments.It was found that the nano-hydrogels we produced were reduced in particle size at pH 5.5 and above 31 °C.It shows that it can release the drug according to the environmental changes.Finally,a kind of nanogel with a drug loading rate of 28.02% was obtained,and the release amounts were 8.41%,31.25%,and 14.28% at pH 7.4,pH 5.5,and pH 4.5,respectively.The innovations: A kind of nanogel with double sensitivity of pH and temperature was prepared,which can be released under the environment of human solid tumor.And the pH responsiveness of the hydrogel can be changed by changing the ratio of the raw materials,so that it can be applied to release in different environments.The preparation method is safe and simple,and no toxic solvent and substance are used,and the product has high safety.