Preparation And Application Of Photoelectrochemical Sensor Based On TiO₂ Mesocrystals

Photoelectrochemical sensor is a detecting device which by virtue of the photoelectrochemical performance of photoactive materials to determine the concentration of target. Due to the complete separation of excitation source ?light? and detection signal ?current? in the photoelectrochemical detection, the undesired background signal was greatly reduced, which make photoelectrochemical technology show the unique superiority and broad application prospects in the analysis detection and biomolecular recognition.In this thesis, the titanate ?KxH2-xTi6O13? nanowires synthesized by a simple hydrothemal method were used as precursors for preparing a series of TiO₂ mesocrystals with unique morphology, and then they were used for the fabrication of novel photoelectrochemical sensor based on different sensing mechanisms.1. quasi-octahedral shape TiO₂ mesocrystals used as photoactive materials were modified onto the carbon nanohorns modified electrode, and then the target ?4-methylimidozal, electron donor? was added into the detecting solution to enhance the photocurrent, realizing the ultrasensitive detection of 4-methylimidozal.2. A delicate amplify strategy was firstly proposed by coordinating dopamine with undercoordinated titanium atoms of TiO₂-B nanorods to form a hybrid, then by virtue of the high biospecific affinity between concanavalin A and glucose molecules to make glucose self-assemble onto the electrode surface for inhibiting the photocurrent, which the glucose concentration in saliva can be detected by recording the photocurrent.3. Through the immune recognition reaction between a-fetoprotein antigen and antibody and the catalysis of enzyme to trigger the generation of CdS for improving the photocurrent of octahedral TiO₂ mesocrystals, which the multiplex amplification strategy successfully achieved the ultrasensitive detection of a-fetoprotein.