The Study Of Marine Toxin Rapid Detection System Based On Smartphone

With the accelerating industrialization process around the world and increasing marine pollution,the number of occurrences of red tides in coastal areas of China has soared,reaching 40 to 50 times per year.The toxic algae in the red tide and the heavy metals discharged into the ocean with industrial sewage are ingested by marine organisms.After accumulation and transformation,they form marine biotoxin toxins,which endanger the health of the consumers,leading to serious food safety emergency.Marine toxins had an adverse impact on seawater quality and aquaculture.The traditional marine toxin detection method is professional with a long detection period and huge instruments,and the laboratory is far away from the coastline,which can not meet the needs of on-site monitoring.Therefore,the rapid on-site detection of marine toxins has gradually gained attention.We designed and implemented on-site rapid detection of marine toxins based on smartphones in this paper.The main detection targets are marine biotoxins-representative paralytic shellfish toxins,saxitoxin(STX)and heavy metal ions Cd6+.By the self-developed portable optical detection instrument for smartphones,nano-materials are used to establish biosensors(immunosensors,aptamer sensors and cell sensors)to detect the paralytic shellfish toxin,saxitoxin STX and heavy metal ions.These Optical biosensing methods were designed for the toxicity evaluation of marine toxins,primary screening and rapid on-site detection to prevent marine toxin poisoning events.The main work and innovations completed in this paper are as follows:1.A new portable optical detection system based on smartphones was designed to achieve on-site rapid detection of marine toxins.A portable optical detection system based on smartphone(SBCA)was designed to detect changes in absorbance of biochemical experiments.Optimized by structure and algorithm,SBCA integrates cold light sources,fiber optics,neutral filters and other optical components into the system and uses a mobile phone as a processor.making it a portable and accurate on-site colorimetric instrument.In addition,SBCA is comparable to commercial microplate readers in biochemical analysis.The appropriate channels are available in four color channels(RGB and Gray)for biochemical testing of multiple color products.Combined with on-site rapid detection and screening of corresponding testing experiments,SBCA is a low-cost and sensitive detection system that enables rapid on-site detection of marine toxins and immediate information to avoid emergency safety accidents,which may be applicable to the sea in the future.Large-scale sample field testing of product safety.2.An enzyme-linked immunosorbent assay combining nanogold and biotin-streptavidin has been proposed to improve the sensitivity of STX detection.In this paper,three enzyme-linked immunosorbent assays for STX were proposed,including(1)indirect enzyme-linked immunosorbent assay(detection limit:5 ng/mL,detection range:10?20 ng/mL).(2)biotin-streptavidin Indirect competitive enzyme-linked immunosorbent assay for detection of STX by immunoassay(detection limit:3.2 ng/mL,detection range:5?200 ng/mL)(3)nanogold-enhanced Indirect competitive enzyme-linked immunosorbent assay for detection of STX(detection limit:0.4 ng/mL,detection range:1-200 ng/mL).After the addition of nanomaterials,the sensitivity of the traditional enzyme-linked immunosorbent assay was improved,and the detection limit was reduced by 12.5 times.The recovery experiment proved that the enzyme-linked immunosorbent assay for the detection of STX has a recovery range of 89.1?112.2%and a coefficient of variation(CV)of 4.6?23.2%.The average recovery rate is over 85%,which can meet the needs of on-site inspection.3.A low-cost and practical biosensor based on nucleic acid aptamer was designed,and the application method and feasibility of the sensor in detecting STX were explored.In this paper,a colorimetric method for the detection of marine toxin STX in combination with nanogold and nucleic acid aptamers M-30f was proposed,and the results of the portable optical detection instrument SBCA were used.The linear curve of the standard curve was 0.9820 and the detection limit was 314.6 ng/mL.The colorimetric reaction time of detecting marine toxin STX with nano gold and M-30f nucleic acid aptamer is rapid,and the nucleic acid aptamer is easy to prepare and low in price.It is expected to become a new screening means of marine toxins detection in marine aquatic products in the future.4.A new method based on cell sensor for the detection of marine heavy metal toxin Cr6+ions and its toxicity evaluation was proposed.Preliminary experiments show that this method can be used for on-site rapid biotoxicity evaluation of heavy metals.A detection method based on smartphone-based optical detection system-Bionic e-Eye combined with cell activity sensor(CVB)for heavy metal toxicity evaluation was proposed.CVB is a cell sensor that uses living cells as a sensitive component and a cell counting reagent(CCK-8)as a secondary transducer to convert the activity parameters of cells into optical signals.CVB was constructed using human hepatoma cell line(HepG2),and HepG2-CVB constructed with a cell density of 4000 cells/well was able to respond to Cr6+ ions in the range of 0.5?5 mmol/L.The optimal detection time was 5 h.The detection limit is 0.48 mmol/L.This method is a portable,low cost,easy to operate and highly efficient method for rapid on-site biotoxicity evaluation of heavy metals.