Electrochemical Impedance Spectroscopy Study Of BSA Adsorption On Chitosan And Arginine Modified Chitosan Surface

The behavior of protein adsorption on solid surfaces plays an important role in many industrial and medical processes. Although great progress has been made in the research of protein adsorption on solid surfaces in recent years, people know little about protein adsorption mechanism. Now the change of configuration and orientation after protein adsorption on surfaces can't accurately be predicted. But it is very important to predict it for understanding, controlling and making full use of protein biological process at interface. It is necessary to select advanced equipments to study protein adsorption. Electrochemical impedance spectroscopy (EIS) is a powerful method to study the interfacial phenomenon including protein adsorption, it can be used to in another hand, chitosan and its ramification have extensive application in biomaterial and biosensors.So in this study, the adsorption behavior of bovine serum albumin on chitosan surface has been studied over the temperature range 293-333K using electrochemical impedance spectroscopy. The impedance spectra were interpreted in terms of an equivalent electrical circuit (EEC) based on a possible physical model with the circuit elements representing the electrochemical properties of the investigated system. The adsorption amount increased with the increase of the BSA bulk concentration in the beginning, and then it didn't depend on the concentration. Besides, the higher the temperature, the greater amount was. Through thermodynamics analysis, the Gibbs free energy, the value of enthalpy and entropy of adsorption were obtained. The result showed that the adsorption process on chitosan surface is slightly exothermic; the large positive entropy of adsorption contributes substantially to the driving force for adsorption. The adsorption process was a spontaneous process. Compared with the results obtained by quartz crystal microbalance, both of the results showed that BSA adsorption on chitosan obeys Langmuir isotherm adsorption equation, and the adsorption layer is monolayer. One can conclude that EIS is one effective means for study protein adsorption on polymer surface and can get some useful information.The study of protein adsorption on chitosan surface has proved the feasibility of using EIS to study protein adsorption on polymer surface. In order to confirm the conclusion and study the protein adsorption characteristic, we also use EIS to study BSA adsorption behavior on arginine modified chitosan surface. The results showed that the EEC selected can be used successful to model the physical property of protein adsorption. The solution resistance (Rs) decreased with the increase of bulk solution concentration or adsorption temperature. The arginine modified chitosan surface has no surface charge, but...