| With the progress of science and technology and the development of national economy,people's living standard has been greatly improved.How to improve the quality of life has become a more important topic for modern people.Three meals a day is the closest thing to People's Daily life,food and agricultural safety issues are closely related to everyone.In recent years,several food safety accidents have caused widespread panic among the people.The state and government attach great importance to food safety issues closely related to people's livelihood.Foodborne pathogens are the main reason for the failure of food safety,and the first solution to the quality control of food and agricultural products is the detection of foodborne pathogens in food.Current detection of foodborne pathogens is still the most commonly used method is one of the traditional flat notation,according to the national standard method to detect food processing after the sample solution and diluted,and then after 48 hours to cultivate the observation after growth of colony,the statistical number of colonies and according to the sample dilution multiple and the inoculation amount that calculates the number of bacteria in the sample.This classic method for its high accuracy(can be accurate to a single bacteria)has been adopted by the quarantine department,but the defect of classic methods is also very obvious,because the training time is long,when some emergency need to quickly get test results for pathogen information obviously the traditional method can't meet demand,and bacteria culture need professionals to operate,hindered the widespread popularization of this method.Based on the defect of traditional detection method,the fast detection method of foodborne pathogen was born.The attention put on high rapid pathogens detection methods are mainly based on the detection method based on molecular biology,bacteria detection method based on immunology and automation rapid detection method based on the biosensor.The more mature and representative methods are polymerase chain reaction(PCR),enzyme-linked immunoassay(ELISA)and tagged electrochemical biosensor.These methods have a short detection time,and the detection accuracy is not as good as the classical method,but it is enough to meet the needs of rapid detection.However,the first two methods invariably have higher requirements on the detection personnel's skills,and the expensive testing instruments are in the laboratory stage,which is not conducive to the popularization and promotion in the later stage.Moreover,most of these methods require tedious pretreatment process,such as marking the pathogen.For this situation,this subject studies the detection method,a new type of bacteria the method combined with biological sensor composed of nano materials,don't need to make marking,tested bacteria and short detection time,high specificity,good reliability,without complicated pretreatment can get conform to the requirements of the test results.Biosensor technology has been an important means to detect microorganism,gas,macromolecular material,etc.,and it is also an important means to realize automatic detection of foodborne pathogens.In recent years,the combination of biosensors and electricity,chemistry,materials and immunology has made it a great development in microbiological detection.In particular,the application of nanomaterials has brought broad development space to biosensors.Graphene is one of the most prominent research hotspots in nanomaterials today.It consists of a single layer of carbon atoms in a honeycomb arrangement.Graphene has excellent electrical,optical and mechanical properties of the material science,biology,medicine,energy and other fields has a good application prospect,has been hailed as the most development potential of the two dimensional nanomaterials.Pure graphene has a high electron mobility,is ten times the silicone material,the surface of graphene has very strong adsorption,can be combined with a variety of molecules and microbes: at the same time,its unique twodimensional structure monolayer of carbon atoms make graphene unusually sensitive on the surrounding environment,when there are other charged molecules or materials are adsorption,on the surface of the graphene doping electron mobility of graphene will produce obvious change,causing the graphene itself resistance change.Based on this,graphene is well suited to the receiving end of biosensors.This issue analyzes the existing bacteria detection technology and its insufficiency,the graphene field-effect tube detection principle,technology development and application of biological sensors,on the basis of this paper expounds the research content,mainly including the composition of the whole test system and the design idea and realization method of all parts.This paper combines the nano materials and biological sensors,this paper proposes a new method of rapid detection of escherichia coli,and on the basis of the theoretical experiment designed a set of on-site rapid detection of escherichia coli concentration system.The system is mainly composed of front-end biological sensor unit,resistance measurement unit,signal processing and control unit,display unit,the core part of graphene biological sensors and signal processing part of the weak current signal.The core work of this project is the preparation of graphene biosensor,the construction of the circuit part of the rapid detection system and the preparation and debugging of the software program.Verified by the experiment,we design the rapid detection of escherichia coli system has a good accuracy and reliability of testing time control within 30 minutes,in food and agricultural product inspection field has a good application prospect.The development of future biosensors and nanomaterials will bring about unprecedented changes in the detection of rapid bacteria. |
PDF Full Text Request