Synthesis Of AIE Functionalized Mesoporous Silica Nanomaterials For Biomedical Application

With the development of cancer theranostic,imaging-guided,visualized cancer therapy has attracted much attention because of the high therapeutic efficiency and low side effects.Based on the unique structural characteristics(such as high specific surface area and suitable pore size)and the excellent biocompatibility,mesoporous silica nanomaterials(MSNs)are expected to be ideal carriers for drug delivery.Fluorescent MSNs have drawn increasing research interest for their potential application in imaging-guided therapy.However,when aggregation-caused quenching(ACQ)molecules are introduced into the inorganic matrixes,the emission of obtained materials may be quenched,which is harmful to their application.Compared with the ACQ system,the aggregation-induced emission(AIE)luminogens can exhibit strong emission in the solid state because of restriction of intramolecular rotation,offering potential for the development of novel inorganic-organic hybrid fluorescent materials.When AIE luminogens are doped into the inorganic materials,their intramolecular motion will be restricted,resulting in typical AIE characteristics.In this thesis,we prepared AIE functionalized mesoporous silica nanomaterials,and explored their biomedical applications such as cell imaging and drug delivery.Utilizing a “surfactant-directing alkaline etching” strategy to synthesize regular hollow mesoporous silica nanospheres(HMSNs),and then 1,2-bis[4-(bromomethyl)-phenyl]-1,2-diphenylethene(BTPE)with blue-emitting AIE core was selected as a model molecule and introduced into HMSNs by postgrafting method to form AIE luminogen-functionalized hollow mesoporous silica nanospheres(FHMSNs).The obtained FHMSNs with large cavity and mesoporous shell show strong blue emission and good biocompatibility.Importantly,such materials exhibit high loading capacity and pH-dependent release of the anticancer drug doxorubicin hydrochloride(DOX).The materials can also function as an effective luminescent bioprobe for intracellular imaging,suggesting the potential application of AIE luminogen-functionalized hollow mesoporous silica nanospheres in imaging-guided therapy.Decorating ultra-small CuS nanocrystals onto the AIE-functionalised mesoporous silica nanoparticles for cell imaging and simultaneous chemo-and photothermal therapies.The obtained nanocomposites exhibit blue emission and good biocompatibility,which can function as an effective luminescent bioprobe for intracellular imaging.Besides,the attached CuS nanocrystals can induce obvious thermal effect after the exposure of 808 nm laser,leading to an evident photothermal anticancer therapy.Meanwhile,DOX as a model anticancer drug was loaded into MSNs via electrostatic interactions,and the release can be apparently enhanced by NIR light,resulting in a synergistic therapeutic effect of combined photothermal therapy and chemotherapy.