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Construction of Interfaces for the Direct Electrochemisty of Hemoglobin and Their Applications in Electrochemical Biosensors

Author: JiaZuoZuo
Tutor: FeiJunJie
School: Xiangtan University
Course: Analytical Chemistry
Keywords: Hemoglobin Direct electrochemstry Biosensors Nitric oxide Hydrogen peroxide
CLC: Q51
Type: Master's thesis
Year: 2009
Downloads: 113
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Abstract

Hemoglobin (Hb), a protein that stores and transports molecular oxygen in mammalian blood, comprises two heme-containing domains. Direct electrochemistry of heme proteins has attracted considerable attentions because it provides fundamental knowledge of the redox behavior of proteins in biological system and is a more effective way of fabricating of biosensors, bioreactors, and biomedical devices than using mediators. Nevertheless, the facilitation of electron transfer between the macromolecule Hb and the electrodes is challenging.In this thesis, several materials with good biocompatibility are used for immobilizing Hb on the surface of electrodes. Based on the interactions between these materials and the protein, the direct electrochemistry of Hb is achieved, due to the preferable orientation of Hb in the films of these materials and the reservation of protein’s natural structure and bioactivity. The main results are summarized as follows:(1) A well-defined amphiphilic diblock copolymer, poly [N-(2-methacryl-oyloxyethyl) pyrrolidone]-block-poly [glycidyl methacrylate] (PNMP-b-PGMA), was applied to immobilize Hb in a simple procedure. The characterization of PNMP-b-PGMA/Hb film was demonstrated by ultraviolet–visible (UV–vis) spectra, atomic force microscopy (AFM), and electrochemical impedance spectroscopy (EIS). The results indicated that the PNMP-b-PGMA film improved the protein loading with the retention of bioactivity and greatly promoted the direct electron transfer between Hb and electrode surface. This PNMP-b-PGMA/Hb film modified electrode also exhibited high electrocatalytic effects towards the reduction of nitric oxide (NO).(2) An unmediated hydrogen peroxide (H2O2) biosensor was prepared by co-immobilizing Hb with platinum nanoparticles enhanced poly (chloromethyl thiirane) cross-linked chitosan (CCCS-PNs) hybrid film. CCCS could provide a biocompatible microenvironment for Hb and PNs could accelerate the electron transfer between Hb and the electrode. Spectroscopic analysis indicated that the immobilized Hb could retain its native structure in the CCCS-PNs hybrid film. Entrapped Hb exhibited direct electrochemistry and electrocatalytic activity to the reduction of hydrogen peroxide(3) A water-soluble cyanoethyl cellulose (CEC) was used as an immobilization matrix to entrap Hb. Spectroscopic analysis indicated that the immobilized Hb could maintain its native structure in the CEC-Hb film.The CEC-Hb film exhibited excellent direct clectrochemical behaviors of Hb and a good electrocatalytic activity for the reduction of NO. Moreover, the studied biosensor exhibited high sensibility, good reproducibility, and long-term stability. Finally, this method has applied to monitoring the NO release from biologic samples.(4) A novel method for the immobilization of Hb and preparation of reagentless biosensor was proposed. Iron oxide magnetic nanoparticles (nano-Fe2O3) by the assembly of hemoglobin on DNA film. The presence of magnetic nanoparticles Fe2O3 in film greatly accelerates interfacial electron transfer of Hb and improves stability of the adsorbed hemoglobin. The prepared DNA-Fe2O3-Hb /GC electrode displayed better ability to keep the bioelectroactivity of Hb and exhibited high electrocatalytic performance to H2O2 and NO with fast response, good sensitivity and excellent stability.

Construction of Interfaces for the Direct Electrochemisty of Hemoglobin and Their Applications in Electrochemical Biosensors

Abstract

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