Electrochemical Chiral Sensor Based On Biological Molecules And Functionalized Nanomaterial

Electrochemical chiral sensors is a new analysis method combining the chiral recognition and electrochemical sensors, with the advantages of fast response, high sensitivity, good selectivity, simple operation, easy miniaturizationand automation. Studies on the interaction between biological molecules and chiral molecules, can help us understand the life process, and has remarkable significance on human biological engineering and pharmaceutical engineering. Nanomaterials have promote the development of electroanalytical chemistry, with the merits of large surface area, strong adsorption capacity and excellent biocompatibility. Based on the above consideration, this paper combined biological molecules as the sensitive element and nanostructured materials with excellent electrochemical properties to construct electrochemical chiral sensor. The main research are included as follows:1. A reagentless electrochemical chiral sensor for discriminating mandelic acid (MA) enantiomers in the presence of Fe(III) was achieved by adsorbing hemoglobin (Hb) on the multiwalled carbon nanotubes (MWNTs) modified glassy carbon electrodes. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) had been used to measure the interactions between Hb and with MA enantiomers in the presence of Fe(III). The results showed that Hb could recognize Fe(III) complexes of MA enantiomers, and larger response signals were obtained from S-MA.2. A reagentless method for selectively electrochemical discrimicating tryptophan (Tip) enantiomers has been developed by means of adsorbing human serum albumin (HSA) on methylene blue-multiwall carbon nanotudes nanohybrid (MB-MWNTs) modified glassy carbon electrode (HSA/MB-MWNTs/GCE). It was found that the developed electrodes exhibited different interaction with Tip enantiomers, and stronger binding effect was obtained from HSA and L-Trp. In addition, the value of the enantioselectivity coefficient (a) and the association constant (k) were calculated.3. The size-controlled gold nanoparticle-methylene blue-multiwalled carbon nanotubes nanocomposite (nanoAu-MB-MWNTs) was successfully synthesized as electrochemical redox-probe indicator and immobilization matrix, which calf thymus double-stranded DNA (DNA) could be adsorbed for chiral sensing propranolol (PRO) enantiomers. The DNA-immobilized sensing platform (DNA/nanoAu-MB-MWNTs/GCE) showed a larger electrochemical response for S-PRO than R-PRO. Quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS) had confirmed the higher affinity for S-PRO with DNA. The experimental parameters such as acidity, incubation time, size of nanoAu and the amount of DNA were assessed to obtain the optimized conditions.