Preparation And Properties Of Hydrogen Peroxide Stimulated Response Materials

As one of the representative reactive oxygen species（ROS）,hydrogen peroxide（H₂O₂）plays an important role in the physiological regulation of various organisms.Therefore,the detection and regulation of H₂O₂ have an important role in the diagnosis and treatment of many diseases related to oxidative stress.According to the change of H₂O₂ concentration level,the occurrence and development of related diseases in the body can be predicted and evaluated.Therefore,it is a meaningful research topic to develop and prepare intelligent materials with H₂O₂ stimulus response performance and indicative properties.Haloysite nanotubes（HNTs）are natural tubular materials with unique microstructure,high aspect ratio,large lumen volume,non-toxicity,and widespread in nature.Based on the H₂O₂ sensitivity of boron-carbon bonds,a H₂O₂stimulus-response hydrogel with fluorescence indicating behavior and color change response was designed and synthesized.Haloysite nanotubes were further introduced as a carrier and developed as a drug carrier.In this paper,we also prepared haloys ite nanotube-based composites and small molecule compounds containing benzoyl groups and tetrastyrene structures with specific responses to H₂O₂,and studied their fluorescence changes under H₂O₂ stimulation.The main research contents are as follows:Chapter 1:This chapter briefly introduces the research progress of hydrogen peroxide-stimulated response materials and HNTs,and puts forward the research purpose and significance of this article.Chapter 2:In this chapter,a fluorescein derivative with two boronic acid groups was synthesized,and a hydrogel was prepared by using a dehydration condensation mechanism with hydroxyl groups in polyvinyl alcohol.And then constructed a H₂O₂stimulation response drug loading system by introducing drug-loaded HNTs.The above system can show strong fluorescence under the condition of H₂O₂ concentration in the diseased tissue,and almost no fluorescence under the condition of H₂O₂ concentratio n in the normal tissue.The introduction of HNTs significantly reduced the burst effect.The B-C bond in the gel system will be broken under the action of H₂O₂ to form a phenol structure and emit fluorescence.The prepared hydrogel is H₂O₂ responsive and can monitor the release of the drug by changing the fluorescence intensity.In addition,the drug’s sustained-release performance and indication effect were detected and compared by UV-fluorescence.The drug release curves of the direct drug-loaded hydrogel and the drug-loaded haloysite nanotube-based hydrogel proved that the latter had a certain inhibitory effect on drug burst release effect.Chapter 3:A phenolphthalein derivative with two boronic acid groups was synthesized in this chapter.A colorless transparent hydrogel was prepared by cross-linking it with polyvinyl alcohol in the same method.The B-C bond in the structure breaks down under the action of H₂O₂ to form phenolphthalein,which gradually turns red as the gel dissolves in a weak alkaline environment.The difference from Chapter 2is that the hydrogel system can directly monitor the H₂O₂ concentration by observing the gel color change with the naked eye.Chapter 4:In this chapter,two compounds containing a benzoyl structure with high specific response to H₂O₂ are synthesized.Then the surface of halloysite nanotubes was modified by silane coupling agent to prepare aminated haloysite,and the molecules containing benzoyl groups were grafted onto the surface of nanotubes.Tetrastyrene-based aggregate fluorescence enhancement effects confer stimulus-response behavior to the product H₂O₂.The comparison of the fluorescence changes of small molecules and haloysite nanotube-based materials under H₂O₂ stimulation was carried out.