Preparation Of An Intelligent Container For Drug Delivery And Its Application In The Field Of Metal Anti-corrosion

Based on the synthesis of a molecular valve with quasi-rotaxane structure,this thesis prepares intelligent drug-delivery containers that can respond to p H,reductant,and metal ions to varying degrees.They are composed of silicon oxide,cysteine,2,2’-dithiodipyridine,cyclodextrin,etc.And through the Fourier infrared test（FT-IR）,X-ray diffractometer（XRD）,isothermal titration calorimetry（ITC）,transmission electron microscope（TEM）,scanning electron microscope（SEM）,1H-nuclear magnetic resonance（NMR-H¹）,element analyzers and other means were used to characterize the materials.Firstly,a hollow silicon oxide sphere（HMS）about 1μm in diameter was prepared as a basic container via the hard template method,with three different thicknesses of 40,75,and 140 nm.Secondly,the thiol coupling agent（KH590/MPTMS）,2,2’-dithiodipyridine,and cysteine are sequentially connected to the HMS by chemical grafting method.The composite material can be used as a p H/glutathione/metal ion-responsive drug container.Rhodamine 6G was selected as the model drug,and the drug release behavior of the material in different p H buffer or solution containing different metal ion concentrations was studied.At the same time,the thickness of the spherical shell,reaction time,and drug size during the preparation process were adjusted to evaluate the effects of these factors on the release behavior of the drug.Many explanations of the response mechanism were made,especially the analysis of the metal ion response and the slight difference in the response mechanism of different metal ion was also show.The results show that the thicker shell and the larger size of the loaded drug will slow down the release behavior,and the optimal time for the disulfide bond exchange reaction is 4h.All metal ion responses utilize the chelation with cyclodextrin,while Fe²⁺shows a little special which will also interact with disulfide bonds because of its reducibility.Finally,to solve the problem that the above materials cannot load small molecule corrosion inhibitors BTA,the existing research data was referred to perform partial molecular replacement of the above materials,and the resulting smart container can be loaded with 2 kinds of metal corrosion inhibitors.The corrosion inhibition effect of 2 kinds of corrosion inhibitors on Q235 carbon steel,copper,and AZ31s magnesium alloy was evaluated by electrochemical impedance test（EIS）.The corrosion inhibitor exhibited corrosion inhibition effect,indicating that the intelligent container loaded with corrosion inhibitor has potential applications in metal smart coatings.When the smart containers loaded with a corrosion inhibitor are directly put into a neutral corrosion medium of magnesium alloy,the behavior of metal corrosion can be observed to slow down with the release time of the corrosion inhibitor by electrochemical methods.In summary,the smart container prepared in this paper has potential application value as a controlled release material in the field of metal corrosion and protection.