Preparation Of Biosensors Modified By Glycosaminoglycan And Their Application In Detection Of Major Zoonotic Diseases

Zoonosis is a contagious disease that can be transmitted from animals?wild and domestic?to humans or from humans to animals.Zoonotic diseases not only endanger human health,but also cause loss of livestock and by-products,which bring great harm to society and economy.Therefore,it is urgent to strengthen the early detection of zoonotic diseases.However,not all vaccines for diseases can perform their proper functions,so detection is becoming the most effective mean of blocking.Traditional methods have their advantages,but the disadvantages are also obvious.Electrochemical biosensors have attracted much attention due to their high sensitivity,selectivity,ease of use,fastness and stability,and simple instruments.They are widely used in disease detection,food analysis,environmental analysis,and defense.However,the current bottleneck is that it is impossible to exclude interferences from organic and inorganic compounds as well as various enzyme and protein contained in the sample.As a result,the sensitivity and accuracy of the detection methods are reduced.In this work,three antifouling interfaces were constructed,which were applied to the detection of disease markers in serum.1)Based on the preparation,identification and purification of the specific antigen of Brucellosis,a novel brucellosis electrochemical immunosensor with ultraselectivity and ultrasensitivity was constructed by the synergy of glutathione?GSH?and hyaluronate?HA?.Electrochemical immunosensors were characterized by scanning electron microscopy?SEM?,energy dispersive spectroscopy?EDS?,Fourier transform infrared spectroscopy?FT-IR?,electrochemical impedance spectroscopy?EIS?and differential pulse voltammetry?DPV?.Under optimized conditions,the detection linear range is2.08×10^-1515 g mL^-11 to 1.04×10^-1212 g mL^-1,and the detection limit?LOD?is as low as 0.50fg mL^-1?S/N=3?.This LOD is lower than the results of most existing methods,indicating the immunosensor has feasible commercial value in practical detection.2)AnelectrochemicalDNAbiosensorwasconstructedbasedon Fe₃O₄@Au@PEG@CS NPs which was applied in mycoplasma pneumonia detection.First,differential pulse voltammetry was used to investigate the antifouling property of themagneticglassycarbonelectrode?MGCE?surfacemodifiedwith Fe₃O₄@Au@PEG@CS NPs in single protein solutions?bovine serum albumin?BSA?and OMP31?or complex solutions?DNA mixture,100%goat milk and 100%serum?.Studies had shown that the DPV response current change of the interfaces before and after incubation in 100%serum was only 0.79%,which layed the foundation for the successful construction of DNA biosensors with antifouling,high selectivity and sensitivity.Therefore,the subsequently constructed mycoplasma pneumoniae biosensor has a unique specificity for the target DNA in 100%serum.The linear detection range of the sensor is10^-1717 M to 10^-1111 M,and the low detection limit is 3.30 aM.This result indicates that the DNA biosensor has enormous clinical diagnostic potential.3)Another novel antifouling electrochemical DNA biosensor based on chondroitin sulfate?CS?was constructed for the detection of tuberculosis.Firstly,Au nanoparticles?Au NPs?were electrochemical deposition on the surface of glassy carbon electrodes.Polyethyleneimine?PEI?was then immobilized on the surface of the Au NPs modified electrode by Au-N bond.Subsequently,chondroitin sulfate was then immobilized on the polyethyleneimine modified surface by covalent attachment.1,4-butanediol diglycidyl ether?BDDGE?was used as a crosslinking agent when the capture DNA related to tuberculosis is then fixed.The developed DNA biosensor has high selectivity,excellent sensitivity and good stability.For target DNA,the linear detection range was between10^-1616 M and 10^-1010 M,and the detection limit was 0.03 fM?S/N=3?.Therefore,the proposed novel electrochemical DNA biosensor will have broad application prospects in disease detection and clinical diagnosis.