Construction Of Visualization Sensor Based On Aunps And Its Application

Traditional sensor technology in the sensitivity,response time,equipment maintenance exist some shortcomings.So the development of faster and better sensor is particularly important.Nano-gold has the characteristics of strong surface effect,good biocompatibility and excellent heat conduction effect.Therefore,the sensor based on nano gold can be applied in the fields of biology,environment and medicine.The main research contents of this subject include two parts:(1)Cr3+/Pb2+ was detected by tyrosine-modified nano-gold-based sensing system.Firstly,nano-gold particles with a diameter of 13 nm were prepared by tyrosine modification.The specific binding of tyrosine to Cr3+/Pb2+ ions was used to make the gold nanoparticles agglomerate and the color of the body fluid changed from red to blue and purple.By optimizing the concentration of sodium chloride and p H,the detection limit and response time of the system were effectively reduced and the recyclability of the detection system was realized.The minimum detection limits were 30 nmol/L and 50 nmol/L.The chi-square values were above 0.99.The experiment also proved that the system had good selectivity and anti-interference by adding 13 kinds of different metal ions,and by analyzing the nano-gold particle blank system under different storage time and the A580/A520 value after adding Cr3+/Pb2+ system has good stability.Finally,a good detection system is successfully applied to the detection of simulated samples,and the highly sensitive and highly selective detection of heavy metals based on nano-gold sensing system is realized.(2)Construction of high sensitive DNA biosensor based on AuNPs.In the experiment,the concentration of PDDA/probe DNA/ probe DNA/Mg2+,p H and target DNA hybridization conditions were discussed.The optimal hybridization conditions were as follows: 37 oC water bath 1h.Under the optimal experimental conditions,the change of the target DNA concentration,the establi shment of the standard curve,the detection limit can reach 0.01 nmol/L,the chi square value more than 0.99.And then through the design of two mismatched DNA sequence to verify the selectivity of the system,through the A620/A520 ratio found that the system has a good selectivity.At the same time,in order to further prove the universality of the method,the experiment also designed another DNA fragment used to detect kanamycin,the minimum detection limit of up to 0.1 nmol/L.The results show that the system has good specificity and selectivity for kanamycin.Finally,the system was characterized by DLS and TEM and Zeta potential test respectively,and the feasibility and mechanism of the system were further proved.This topic overcomes some shortcomings in the previous research,such as the high detection limit,the long detection time,the high cost,can not be real-time detection and other shortcomings,which can be related to the subsequent research to provide better technical support.