title: Aptamer-based biosensors for label-free voltammetric detection of lysozyme.
abstract: This paper reports a simple electrochemical approach for the detection of the ubiquitous protein lysozyme using aptamer-modified electrodes. Anti-lysozyme DNA aptamers were immobilized on gold surfaces by means of self-assembly, for which the surface density of aptamers was determined by cyclic voltammetric (CV) studies of redox cations (e.g., [Ru(NH3)6]3+) bound to the surface via electrostatic interaction with the DNA phosphate backbone. Upon incubation of the electrode with a solution containing lysozyme, the CV response of surface-bound [Ru(NH3)6]3+ changed substantially, and the relative decrease in the integrated charge of the reduction peak can be tabulated as a quantitative measure of the protein concentration. It is significant that the on-chip protein/aptamer binding constant and the optimized surface density to achieve the best detection limit can be evaluated. This biosensor is label-free and offers an alternative, sensitive, and versatile method for protein detection, which is beneficial to the ever-growing interests of fabricating portable bioanalytical devices with simple electrical readout protocols.
authors.affiliation: Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
authors.forename: Alan K H
authors.initials: AK
authors.lastname: Cheng
authors.forename: Bixia
authors.initials: B
authors.lastname: Ge
authors.forename: Hua-Zhong
authors.initials: HZ
authors.lastname: Yu
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000737:chemistry*; D004566:Electrodes; D005292:Ferricyanides / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D009113:Muramidase / Q000032:analysis*; D010084:Oxidation-Reduction; D011199:Potentiometry / Q000379:methods*; D012996:Solutions / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D005292:Ferricyanides; D012996:Solutions; D006046:Gold; D004247:DNA; D009113:Muramidase