Hemoglobin immobilized on ionic liquid modified functionalized multi-walledcarbon nanotubes

Recently nanocomposite materials have aroused great attentions in the field of chemistry due to their extraordinary properties such as thermal stability and high conductivity and one of their significant characteristics is that the proteins adsorbed on the electrode can still retain their activities. Direct electrochemistry behavior of redox proteins is important for the research of theirmetabolic processes and construction of the biosensors and bioreactors. However, the directelectron transfer (DET) between proteins and bare solid electrode is difficult because the electroactive centers are embedded deeply in the protein structure, as well as adsorptivedenaturation and unfavorable orientations of proteins on electrode surfaces [۱]. In present paper,we used the simple casting method to immobilize Hemoglobin (Hb) on the surface of carbonionic liquid electrode (CILE), which was constructed of graphite powder and ionic liquid, ۱-butylpyridinium hexaflourophosphate ([BuPy][PF۶]), achieved direct electrochemistry of Hb and investigated electrocatalytic properties of Hb [۲].For biosensor preparation, ۵ mg of MWCNTs and ۳۸ mg of BPPF۶ were added into ۲.۵ ml of N, N-Dimethyl formamid (DMF) solution as the stock solution. After approximately ۱۵ min ofsonication, uniformly dispersed MWCNTs-BPPF۶ were formed .Then ۱۰ μL of the prepared suspension was dipped onto GCEs to obtain the MWCNTs-BPPF۶/glassy carbon (GC)-modifiedelectrodes. After being air-dried, the MWCNTs-BPPF۶-modified electrodes were immersed intothe aqueous solution of Hb (۱۰ mg Hb/۳ mL PBS) for ۲۴ h. The electrodes were then rinsedthoroughly with distilled water to remove the nonadsorbed Hb. The modified electrodes werestored in PBS in a refrigerator when not in use.The process can be expressed as follows:Fe(III) + H۲O۲ Compound I + H۲O*Compound I + ۲e- + ۲H+ Fe(III) + H۲OWe have demonstrated that the hemoglobin was immobilized on the surface of CILE/GC electrode and the direct electron transfer of hemoglobin was assessed by cyclic voltammetry. Hb/CILE/GC electrode showed a great sensitivity for H۲O۲.

کلیدواژه ها:

Hemoglobin ، Biosensor ، Bioelectrochemistry ، Bioanalysis