Electrochemical Chiral Recognition Of Penicillamine Enantiomers

Chirality is a univeral phenomenon in nature, and represents the most essential nature of life process. Chiral materials which contain chiral centers have high application value in life science, medicine, pharamaceutical science and food science. Especially for chiral drugs, the different configurations of enantiomers may exhibit significant difference in metabolic processes, pharmacological efficacy and toxicity, duing to a close relationship between drug properties and the stereochemical structure of drug molecules. Thus, in recently, it is a research focus of analysis chemistry and to overcome the difficulties to develop the chiral recognition techniques with the merits of simple, rapid, accurate and low cost. There are many methods for chiral recognition, which live made certain progress, in which the electrochemical techniques gain the researches favor and provide powerful means for chiral recognition because of its fast detecting speed, low cost, high sensitivity and low detection line. Electrochemical sensors constructed by different principles and methods have realized the chiral recognition of penicillamine (Pen) enantiomers in this article. The main research jobs are as follows:1. Double-stranded DNA and multi-walled carbon nanotubes (MWNTs) were used to prepare the functional nanomaterials (DNA-MWNTs complex), then were constructed on the modified glassy carbon electrodes surface (DNA-MWNTs-GCE). Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM) and ultraviolet-visible spectroscopy (UV-Vis) were used to characterize the enantioselective phenomenon of Pen enantiomers and DNA-MWNTs complex. In addition, the interaction time and the amount of DNA-MWNTs complex for the chiral discrimination of Pen were systematically investigated by CV. These results indicated the binding effect between L-PA and DNA-MWNTs was stronger than that of D-PA and DNA-MWNTs.2. We reported the sol-gel encapsulation method to immobize protein in this work. BSA embedded in ultrathin AlO3sol-gel film was coated on the surface of glassy carbon electrode (BSA/GCE). The scanning electron microscope technique had been utilized to discuss the surface morphous before and after Al2O3sol-gel encapsulated BSA. CV, EIS and UV-vis absorption spectroscopy technique were used to investigate the chiral surface recognition of Pen enantiomers under the optimal conditions. The influence of amount of BSA, incubation time, pH and the concentration of Pen enantiomers for the chiral recognition were investigated by C V, systematically. The association constant (K) between BSA and D-/L-Pen was calculated, respectively. These results indicated BSA had different adsorptive effect to Pen enantiomers and a larger electrochemical response was gain from BSA and D-Pen. This work not only did help further to comprehend the interaction between proteins and chiral drugs, but also provide some valuable reference for analysis of chiral drugs.3. This work used the macrocyclic antibiotics (vancomycin) modified membrane to discriminate Pen enantiomers. Firstly, the chiral surface was constructed by vancomycin (Van), and then the CV and EIS were adapted to investigate the enantioseletive adsorption of Pen enantimers on the chiral surface. The results showed that a different electrochemical signal exhibited on D-Pen-Van-surface and L-Pen-Van-surface, and D-Pen-Van-surface had a larger electrochemical response. At the same time, AFM was also used to research the adsorption behavior of Pen on the chiral surface. The result indicated that Van adsorbed the more amount of D-Pen over L-Pen, which was in accordance with that of CV. It was the first time for Van to be used in the chiral disctimiation of Pen by amperometric electrochemical sensor. The preparation of the chiral surface is simple, sensitive reaction and good results. This work can provide the basic research for another macrocyclic molecules using in chiral recognition based on the above advantages.