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Direct electrochemistry of hemoglobin adsorbed on self-assembled monolayers with different head groups or chain length
- Source :
-
Talanta . Apr2010, Vol. 81 Issue 1/2, p167-175. 9p. - Publication Year :
- 2010
-
Abstract
- Abstract: The electrochemical behaviors of hemoglobin (Hb) were studied by adsorbing Hb on the gold electrodes modified with self-assembled monolayers (SAMs) of different terminal groups and alkyl chain length. Specifically, through adsorbing the Hb molecules onto the SAMs of 3-mercaptopropanoic acid (MPA), 1-propanethiol (PT) and cysteamine hydrochloride (cys), the influences of the terminal groups of alkanethiols on the electron transfer of Hb were examined. A quasi-reversible redox process was observed when Hb was adsorbed on the MPA-modified electrode. However, an irreversible reduction process and no redox response were shown when Hb molecules were adsorbed on the SAMs of PT and cys-modified electrodes, respectively. The dependence of the direct electrochemical response of Hb on the alkyl chain length of alkanethiols (n) was further investigated on the SAMs of HS(CH2) n COOH (n =1, 2, 5 and 10). When n was 1, Hb showed a weak current response. When n were 2 and 5, quasi-reversible redox processes with nearly similar electron transfer rate constants (k s) of 0.49 and 0.47s−1 were obtained, respectively. Increasing the number of methylene groups within carboxyl alkanethiol to 10 resulted in a significant decrease of the electron transfer rate and current response of Hb. The observations indicated that the SAM of MPA can provide suitable properties to keep Hb in a favorable adsorption state for direct electron transfer (DET). Furthermore, the direct electrochemistry of the Hb adsorbed on the SAM of MPA was studied in detail. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 00399140
- Volume :
- 81
- Issue :
- 1/2
- Database :
- Academic Search Index
- Journal :
- Talanta
- Publication Type :
- Academic Journal
- Accession number :
- 48401671
- Full Text :
- https://doi.org/10.1016/j.talanta.2009.11.053