Design,Construction And Cu(Ⅱ) Detection Application Of Functionalized Mesoporous Silica Fluorescent Nanoprobes

Organic-inorganic mesoporous silica hybrids which combine the functionality of organic groups and structural features of mesoporous silica materials have attracted increasing research interests in sensing,adsorption,catalysis and drug carriers.In recent years,fluorescent nanoprobes based mesoporous silica with controllable morphology,excellent luminescence performance,and superior photochemical stability have been widely used in the sensing of heavy metal ions.High optical stability and good recyclability are exhibited for these mesoporous silica fluorescent nanosensors.In addition,the low cytotoxicity of functionalized mesoporous silica nanoprobe with makes them become excellent candidates for biological and environmental sensing applications.In this thesis,the synthesis,detection and application of functionalized mesoporous silica nanoprobes were studied.Two mesoporous silica fluorescent nanoprobes based on benzimidazole derivatives（DHBM）and Schiff base derivatives（SCN）were prepared by post-modification and condensation methods,respectively.The material structures and optical sensing properties of two copper ion nanoprobes were investigated,and their fluorescence imaging performance in cells or organisms were explored.The main study components are as follows.（1）A benzimidazole derivative（DHBM）was synthesized by a one-step reaction and then grafted onto the surface of mesoporous silica materials（DHBM-MSN）.The successful synthesis of mesoporous hybrids was verified The highly ordered mesoporous structure was maintained after functionalization.Mesoporous silica hybrids with different morphologies were synthesized,which were used to study the effect of morphologies on the detection.（2）The detection conditions of fluorescent receptor DHBM was investigated.DHBM had specific response to Cu²⁺in aqueous solution and the detection behavior of DHBM could remain stable over a broad p H range（p H 7.0～10.0）.The DHBM-MSN sensor showed an obvious quenching effect on Cu²⁺in aqueous solutions.qualitative and quantitative Cu²⁺detection could be realized by DHBM-MSN.The detection limit could be as low as 7.69×10^-8 M and good antiinterference performance was exhibited.In addition,the morphological structure of material does not affect the detection ability of probe.The detection mechanism of the fluorescent probe was systematically elucidated by combining experimental results and density function theory calculations.Moreover,the detection system was successfully applied for Cu²⁺detection in bovine serum,juice,and live cells.These results indicate that the DHBM-MSN fluorescent sensor holds great potential in practical and biomedical applications.（3）A novel Cu²⁺sensing periodic mesoporous organosilica（SCN-PMO）with ordered mesoporous structure was prepared by introducing a Schiff base fluorescent ligand into the pore walls of mesoporous silica.SCN-PMO showed high selectivity and sensitivity fluorescence response towards Cu²⁺based on its specific ligand binding effect.The detection limit of SCN-PMO could be as low as 6.7×10^-7 M.Due to protection of the silica network,SCN in PMO exhibited higher photostability.Meanwhile,the hybrid material had great recyclability.Additionally,the fluorescence sensing of Cu²⁺in zebrafish could achieved by SCN-PMO.These results indicated that SCN-PMO has potential applications as a nanoprobe in biological fields.