Construction And Study Of Photoelectrochemical Immunosensor For Rapid Detection Of Vibrio Parahaemolyticus

With the advance of scientific technology and the improvement of living standards,health issues are increasingly concerned by people.Now foodborne diseases have become one of the biggest threats to public health in the world.The food poisoning events caused by Vibrio parahaemolyticus(VP)has increased in recent years,and it has been limited to coastal areas at first and spread to every regions at present.The harms of food poisoning caused by VP are very big.The current detection methods are mostly limited to long detection time,complicated detection process,high detection cost and unrealizable on-site detection.Therefore,it is necessary to develop a rapid detection method for VP with a wide detection range,a low detection limit,and a low cost.In this study,a photoelectrochemical immunosensor based on CdSe sensitized Ho³⁺/Yb³⁺-TiO₂ was assembled and used to detect the VP.The Ho³⁺/Yb³⁺-TiO₂ sample was successfully prepared by hydrothermal method.Compared with the pure TiO₂ sample,the sample of doping rare earth element has a smaller particle size and more higher photocurrent responsiveness.When the ratio of Ho³⁺/Yb³⁺is 1:5,the photocurrent is the largest,The photocurrent of Ho³⁺/Yb³⁺-TiO₂ sample with a concentration of 2 mg/m L can reach 40?A,which is twice than that of pure TiO₂.At the same time,the photocurrent stability and photocurrent performance of CdSe quantum dots prepared by different Cd:Se ratios were compared.When Cd:Se was 1:0.3,the generated photocurrent was the most stable and the storage time was the longest.Using TGA-CdSe quantum dot-sensitized TiO₂ as a photosensitive material,the photoelectrochemical sensor constructed by layer-by-layer self-assembly method has a detection range of 10²-10⁷ CFU/m L and a detection limit of 50 CFU/m L for VP.The photoelectrochemical sensor based on TGA-CdSe quantum dot-sensitized Ho³⁺/Yb³⁺-TiO₂has a detection range of 10²-10⁹ CFU/m L and a detection limit of 25 CFU/m L.The sensor constructed by this method has good specificity,stability and reproducibility.The results showed that the detection performance of the sensor can be improved by increasing the photoelectric activity of the photosensitive material.In addition,the method of detecting quantitative VP by real-time PCR was studied.DNA extraction was performed by DNA kit method,and the gene was detected with tdh gene.The results showed that the detection range was 50-5×10⁸ CFU/m L.It has a good linear relationship with a linear correlation coefficient of 0.993 and an amplification efficiency of 101%.Later,the detection effects of two rapid detection methods on artificially simulated aquatic products were compared.The RSD of photoelectrochemical immunosensors was generally large,and the RSD range was 6.7-20.3%,but the average value was better than that of RT-PCR.