Study On Preparation And Property Of Stimuli-Responsive Polymer/Inorganic Hybrid Materials

Mesoporous materials with well-defined structures have widely applied on drug carriers,biosensors, bio-markers. However, when used as drug deleiver, un-modified mesoporousmaterials show a low drug loading content and can not meet the requirement of controlledrelease. In recent years, the controlled release system, based on the environmental stimuliresponse of mesoporous materials, has caused great attention.Stimuli-responsive polymer （also known as intelligent polymer） has applied on drugdelivery, gene therapy. When a stimulus, such as a change of pH, temperature, or light isapplied, their physical/chemical properties change as a response. After being modified withstimuli-responsive polymers, the hybrid materials can load and control release of drugs, whichis expected to become a new generation of intelligent drug carrier.In this thesis, the main researches are as follows:1. Hollow mesoporous silica nanoparticles （HMSN） were synthesized by sol-gel, whichused DDA as the main template and PVP-10as the co-template. The HMSN-Br was firstlyprepared by reaction of hydroxyl groups on the surface of HMSN with2-bromoisobutyrylbromide, and then it was used as the initiator. Poly （N,N-dimethylaminoethyl methacrylate）（PDMAEMA） was grafted on the surface of HMSN via surface-initiated ATRP. TEM, FT-IR,TGA, XRD and N₂adsorption-desorption analysis were used for the characterization. Theresults stated that HMSN was obtained by a sol-gel process with an average diameter andalmost uniform pore size and the stimuli-responsive polymer had been successfully graftedonto the surface of HMSN.2. Poly （N,N-dimethylaminoethyl methacrylate）（PDMAEMA） was grafted on the surfaceof hydroxy carbonate apatite （HCA） nanoparticles via surface-initiated ATRP. SEM, FT-IR,TGA, N₂adsorption-desorption analysis and DLS were employed for their characterization.The results indicated that the stimuli-responsive polymer had been successfully grafted ontothe surface of HCA and the hybrid materials have a good response to pH.3. The hydrochloric acid doxorubicin （DOX） was used as model drug, and drug-loadingconcent and entrapment efficiency were measured by using fluorescence spectrometry. The drug release behaviors were studied at pH of4.0,6.9and9.0. The results showed that thehybrid materials could load drug efficiently, release drug under acidic conditions and havelittle release under neutral and alkaline conditions.