Research On Cell Sensor And Handheld Detector For Detection Of Marine Toxins

With the development of modern society,the ocean has been contaminated day by day.The marine toxins,which are result from ocean pollution,has become a new threat to human health.Marine toxins,produced by algae,are easily accumulated to a high level in filter-feeding fish or shellfish.People get poisoned commonly by eating the contaminated seafood,and.even to death.Current detection methods of marine toxins include the mouse bioassay(MBA),high performance liquid chromate-graphy(HPLC)and liquid chromatography-electrospray tandem mass spectrometry(LC-MS/MS).Although all these methods have their advantages,there are still many limits for these techniques in practical applications.Nevertheless,each of these methods has their own drawbacks,such as poor repeatability and ethical concerns for MBA,expensive equipment and complicated operations for HPLC or LC-MS/MS.As an emerging technology,cell-based biosensor employed cells as the sensing element and combined the second sensor of physics or chemistry to realize the detection of various compounds.And cell-based biosensor has wide applications in cell research and food detection fields.Besides,a sensing smartphone and its portable accessory could also be utilized for the rapid marine toxin detection.In this thesis,we investigate the two kinds of cell-based biosensors to detect marine toxins on cell level,and develop a sensing smartphone and its portable accessory for on-site rapid biochemical detection of marine toxins.The major contents and contribution of this thesis are as follows:1.Detection of Okadaic acid(OA)using liver cancer cell-based surface acoustic wave biosensorA HepG2 cell-based surface acoustic wave biosensor was introduced in Okadaic acid(OA)detection.The cell culture density was optimized for the toxin detection,and the optimal density was 10,000 cells/well.The insertion loss shifts of sensor have a good relationship with OA concentrations(10-100 ng/mL),which is the correlation coefficient of 0.9834 and the limit detection of 10.91ng/mL.Therefore,the OA concentration could be calculated by the insertion loss shift.Besides,other toxins were also tested to demonstrate the specificity and repeatability of this biosensor.And this research showed that this method has a good potential in OA detection.2.Propose an improved high-throughput assay for the detection of saxitoxin(STX)toxin with cardiomyocyte potential sensorThis article is based on myocardial cell potentiometric sensor system to detect STX.This kind of biosensor could realize synchronous detection for extracellular potentials and improve detection efficiency.Protein modification and cell density optimization were studied for enhancing the coupling of cardiomyovytes and sensor chips.The results show that,for the high-throughput MEA chip,cardiomyocytes seeded with gelatin modification at the proper cell density of 12×104 cells/cm2,prompting high-closely coupling between cardiomyocytes and MEA chips.Under the optimal conditions,this kind of biosensor presented the maximum signal amplitude,the highest frequency and the best repeatability.And this cardiomyocyte potential biosensor was utilized for the STX detection.Through analyzing the specific parameters of extracellular field potential signals(amplitude and frequency),the detection limit was 1.004 ng/mL and the detection range was 7.5-480ng/mL for STX.This cardiomyocyte potential sensor has many advantages such as easy to operate,low detection limit.So it could be a new platform for marine toxin detection.3.A sensing smartphone and its portable accessory for on-site rapid biochemical detection of OA and STX have been developed.A.smartphone-based system cooperating with competitive immunoassay strips was used for rapid on-site detection of OA and STX.The output image could be captured and further analyzed by the smartphone-based system.The detection range for OA was 3-20 ng/mL and for STX was 10-100 ng/mL.The detection limits for OA and STX were 2.800 ng/mL and 9.808 ng/mL,respectively.Other toxins were also tested to verify the specificity of this method.Taking advantage of the smartphone and biochemical analysis,this system will be a promising tool for on-site rapid detection of these marine toxins.