Study Of Functionalized SERS Substrate For Rapid Detection Of Geniculin Toxin And Escherichia Coli In Water

Safe drinking water is a considerable public health issue.Ensuring safe drinking water quality has been a major public health challenge.It is very important to study the microorganism detection in drinking water quality.Detection methods for E.coli in drinking water include conventional detection methods,emerging detection methods and biosensor-based detection methods,as well as detection methods for E.coli markers.Detection methods for biotoxins in drinking water include of immunochemistry methods,gas or liquid chromatography based on coupled mass spectrometry analyzers.These detection methods have their advantages and disadvantages,but there are some problems in the broad spectrum and practical performance.Therefore,it is particularly necessary to develop a fast and sensitive method to meet the needs for rapid field detection.SERS is a very attractive vibration spectrum technology with high detection sensitivity and fast detection speed.SERS detection of water pollutants has been shown to be superior to the traditional detection method.However,the application of the existing SERS detection method is not good enough.Therefore,it is imperative to realize popularization and simplification of SERS method on toxins and pathogenic microorganisms in water bodies.Aiming at the pollution problem of geniculin toxin and Escherichia coli in water body,this paper developed a simple,sensitive and fast response SERS field detection method,making efforts towards the direction of applied research.Aiming at the above goals,this paper carried out the following four aspects of research:(1)Highly sensitive detection of geniculin toxin(GTX)by lysine functionalized SERS monolayer membrane substrate.In this chapter,Lys functionalized gold nanords(AuNRs)were used as nanounits to construct high-density hotspot SERS film base through liquid-liquid interface assembly,and the dynamic SERS detection method was adopted to realize highly sensitive detection of GTX.The Lys functionalized gold nanorods were designed and the highly density SERS film base was constructed.The principle of automatic capture of target molecules by small gaps in functionalized monolayer nanoparticles was discussed.The sensitivity to biotoxin detection was studied.(2)Study on rapid detection method of SERS base on functionalized acupuncture needles for β-galactosidase activity of Escherichia coli marker.The SERS base of PVPAu NP functionalized acupuncture needle was studied.Soluble colorless X-gal hydrolysate catalyzed to produce insoluble blue X-gal hydrolysate was designed as a marker,and the SERS detection principle was discussed.The time and sensitivity of functional acupuncture needles to effectively detect X-gal hydrolyzed products in colonies were investigated.It was verified that the detection strategy of SERS acupuncture needle sensor was necessary and feasible to improve the reliability of bacterial detection and shorten the detection time.(3)Detection of β-galactosidase activity of Escherichia coli marker by polyamideTriton X-114 functionalized SERS substrate.On the basis of revealing the properties of X-gal β-lactosidase hydrolysates,a multifunctional PVP AuNPs-polyamide-Triton X-114 substrate with adsorption enrichment and SERS enhanced effect was explored,and a β-lactosidase hydrolysates analysis method with multiple advantages such as small sample size,high sensitivity and fast detection speed was established.To achieve a highly sensitive detection of E.coli marker β-galactosidase for detection and evaluation of Escherichia coli in water.In addition,the practical application performance of the composites is further investigated.(4)Rapid detection of Escherichia coli in water by sorbate functionalized SERS chip.The best metal nanoparticles were selected,and the interaction between sorbic acid and bacteria was utilized to combine sorbic acid and nanoparticles to prepare SERS chips for rapid detection of bacteria,and its practical application ability was analyzed.The interaction between sorbate and bacteria was investigated.The optimal utilization ratio of nanoparticles and sorbate was screened out,and SERS detection chip was developed,and its detection performance on Escherichia coli was analyzed.The portable Raman spectrometer was used to detect Escherichia coli in simulated water samples after simple pretreatment.