The Construction And Research Of Biosensors In Environmental Monitoring

Biosensors are electrochemical devices that are based on the signal transmission of biochemical reactions, In comparison with the conventional chemical and biochemical analytical methods, the biosensors have the advantages of easy operation, convenience, time-saving, low cost as well as high precision. Moreover, they are convenient for computers to collect and process data, and the sample won't be damaged or polluted.So biosensors have become one of the new technologies in environmental monitoring. Enzyme biosensors have been one of most concerned areas because of their specificity and high-efficiency. In the design and fabrication of electrochemical biosensors,the key technology is to immobilize enzymes or proteins to biocompatible microenvironment. This research was aimed to develop and characterize the active interface that is biocompatible, as well as the application studies in environmental monitoring. The detailed research contents are summarized as follows:The self-assembled mercaptoacetic acid active interface (MAA/Au) and dithiothreitol (DTT)gold nanoparticles active interface (GNPs/DTT+DDT/Au) are constructed on the gold electrode. Based on in-situ functionalization of self-assembled monolayers (SAMs) of 4-aminothiophenol (4-ATP) on gold electrode, 4'-mercapto-N-phenylquinone diimine (NPQD) and 1,4-benzenedimethanethiol (BDMT) are mixed to self-assemble in order to immobilize gold nanoparticles. The active interface GNPs/NPQD+BDMT/Au is constructed.TheHb/Mb-CTS-GNPs/GC active interface is constructed by the chitosan-gold nanoparticles to embed Hb/Mb(CTS-GNPs). The synthesized GNPs is characterized by UV and TEM. Electrochemical characteristics of MAA/Au, GNPs/DTT+DDT/Au, GNPs/NPQD+BDMT/Au are studied by [Fe(CN)₆]^(3-)/(4-)probe. The interferential experiment of MAA/Au, GNPs/DTT+DDT/Au was also carried out. Meanwhile, we investigated the effect of pH and scanning rate on the electro-catalytical effect of MAA/Au, GNPs/DTT+DDT/Au, GNPs/NPQD+BDMT/Au. As a result, the electrode reaction mechanism is revealed. The constructed GNPs/NPQD+BDMT/Au has obvious catalysis for the naphthol isomers that belong to the environmental pollutants, In aqueous solution, trichloroacetic acid,oxygen were catalytically reduced by Hb/Mb biosensors,which suggest that the chitosan-gold nanoparticles retain their activity.