Preparation And Biosensing Applications Of Chalcogenide Semiconductor-Sensitized Nanomaterials

With the special optical,photoelectrocatalytic and photoelectric conversion properties,semiconductor nanomaterials have been widely studied and applied.In this paper,the emphasis is on the exploitation and modification of TiO₂ nanomaterials.With the combination of nanomaterials technology and photoelectrochemical detection technology,aptamer is selected as identification element to detect cytochrome c.The main research contents are as follows:?1?Preparationandresearchonphotoelectricpropertiesof CdS/CuInS₂/Au/TiO₂ NTs.Firstly,monodisperse and spectrally tunable CuInS₂quantum dots were synthesized using a thermolysis method,which had good absorption properties in the visible region.Then the TiO₂ nanotube arrays prepared by anodic oxidation were used as the substrate.After Au nanoparticles,CuInS₂ quantum dots and CdS quantum dots were successively deposited on TiO₂ nanotube arrays by pulse-electrical deposition,immersion and the successive ionic layer adsorption and reaction?SILAR?method,theCdS/CuInS₂/Au/TiO₂nanotubearrayswere successfully prepared.The experimental results showed that the CuInS₂ quantum dots with particle size of 4.1 nm had the best sensitization effect on TiO₂ nanotube arrays.In the optimization experiment of sensitizer load,the photoelectric test results exhibited that the optimum number of pulse-electrical deposition for Au nanoparticles was 30 cycles,the optimal immersion days in CuInS₂ quantum dots tuluene solution were 5 days,and the optimum number of SILAR layers for CdS quantum dots was 7layers.Under the optimized experimental conditions,the photocurrent of the CdS?7?/CuInS₂?5?/Au?30?/TiO₂ nanotube arrays was 2.33 mA/cm²,which was 19timesthatofpureTiO₂nanotubearrays.Itwasindicatedthatthe CdS?7?/CuInS₂?5?/Au?30?/TiO₂ nanotube arrays had excellent photoelectric properties and high stability.?2?A Label-free cytochrome c photoelectrochemical aptasensor based on CdS/CuInS₂/Au/TiO₂ nanotube arrays.With the good photoelectrochemical activity,CdS?7?/CuInS₂?5?/Au?30?/TiO₂ photoelectrode was used as the substrate of sensor.After modified the cytochrome c specific aptamer with a thiol group on the photoelectrode,a label-free photoelectrochemical aptasensor was constructed for the detection of cytochrome c.With the presence of cytochrome c,the aptamer could bind cytochrome c with high affinity and high specificity to form the aptamer-cytochrome c complex.Because of the steric hindrance of the complex,it hindered the carrier's transmission and leaded to the decrease of photocurrent.Thus,the quantitative detection of cytochrome c can be achieved by measuring the change in the photocurrent intensity of the sensor.The results showed that the sensor had a good linear response to cytochrome c in the range of 5 pM-100 nM.And the as-prepared aptasensor exhibited good selectivity and stability.