Todd C. Sutherland

Electronic Biosensors Based on DNA Self-Assembled Monolayer on Gold Electrodes

Information concerning the immobilization and hybridization of DNA on a surface is paramount to the development of DNA-based electronic biosensors. This study looks at recent investigations of DNA immobilized on gold surfaces using standard electrochemical techniques such as cyclic voltammetry (CV), potential step chronocoulometry and electrochemical impedance electrochemical impedance spectroscopy (EIS). The thiol-gold linkage is exploited for the immobilization of single- and double-stranded DNA onto gold electrodes. Two redox markers of opposite charge, ferricyanide and ruthenium hexaammine, respectively, are used to probe the environment in the vicinity of thiol-derivatized DNA electrodes. M-DNA is a form of DNA which allows the specific incorporation of certain metal ions into its helical structure under stringent conditions (i.e. low ionic strength and pH of 8.5). Single-stranded DNA monolayer and double strands DNA monolayer resistances were evaluated using EIS, respectively, and CV response were compared each other. The addition of Zn2+, under M-DNA formation conditions, led to a dramatic enhancement of electrochemical response compared to B-DNA.

Electrodeposition of ferrocenoyl peptide disulfides

Using electrodeposition of cyclic and acyclic Fc-peptide disulfides tightly-packed Fc-peptide monolayers were conveniently formed, which exhibit significant differences in their electron transfer kinetics.

N-Ferrocenoyl-labelled glutamate diethyl ester

Diethyl N-(ferrocenylxadcarbonyl)xadglutamate or N-ferrocenoyl-glutamate-(OEt)2, [Fe(C5H5)(C15H20O5N)], (I), is a derivative of N-ferrocenoylglutamate-(OBz)2, the corresponding benzyl ester derivative published previously [Kraatz, Lusztyk & Enright (1997). Inorg. Chem. 36, 2400–2405]. These redox-labeled amino acid structures exhibit intermolecular hydrogen bonding that leads to extended networks in the solid state and exhibit typical ferrocene one-electron reversible electroxadchemical responses. The asymmetric unit of the structure contains two independent molxadecules, in which the most notable difference is in the conformations of the diethyl ester groups.