Quantitative Photoelectrochemical Detection of Biological Affinity Reaction:  Biotin−Avidin Interaction

Abstract

Quantitative detection of a biological affinity reaction, the biotin/avidin recognition, was achieved using our newly developed photoelectrochemical analytical system. The system is based on the operation mechanism of the well-developed dye-sensitized photoelectrochemical solar cells and comprises a ruthenium tris(2,2'-bipyridine) (Ru-bipy) derivative as the photoelectrochemical signal-generating molecule, oxalate as the sacrificial electron donor, and tin oxide nanoparticle as the semiconductor electrode material. To perform the affinity reaction, avidin was immobilized on SnO(2) electrode by passive adsorption. Biotin-linked bovine serum albumin (BSA) was labeled with an NHS-ester derivative of Ru-bipy. After binding of BSA to the surface-immobilized avidin through biotin, photoelectrochemical measurement was carried out in the presence of oxalate. Anodic photocurrent was turned on and off repeatedly by control of incidental light. The action spectrum of the photocurrent resembled the absorption spectrum of Ru-bipy, proving the photocurrent was generated from the metal complex. A linear relationship between photocurrent and BSA concentration was obtained in the range of 1-100 microg/mL. This is the first case of quantitative photoelectrochemical detection of a biological affinity interaction.

Highly sensitive and selective photoelectrochemical DNA sensor for the detection of Hg2+ in aqueous solutions

“…Injection of the excited electrons into the conduction band of SnO 2 produces photocurrent. Oxalate in the electrolyte acts as an electron donor to regenerate Ru(bpy) 2 (dppz) 2 þ and amplify photocurrent signal (Dong et al, 2004). In the absence of Hg 2 þ , the oligonucleotide maintains a single-strand structure.…”

Enhanced photoelectrochemical method for linear DNA hybridization detection using Au-nanopaticle labeled DNA as probe onto titanium dioxide electrode

“…Guo's group successfully detected biotins quantitatively via the photoelectrochemical label of a Ru-bby derivative as photosensitizer and SnO 2 as the electrode materials (Dong et al, 2004). Then, this work was expanded it into photoelctrochemcial detection of DNA via the oxidation of the guanine bases by photogenerated Ru(III) species (Liang et al, 2006).…”

Photoelectrochemical DNA Sensor for the Rapid Detection of DNA Damage Induced by Styrene Oxide and the Fenton Reaction

“…In addition, the instrument should be simpler and of lower cost than all the optical detection methods due to the use of electronic detection, particularly in an array format. Not surprisingly, numerous studies have emerged which employ the photoelectrochemical method in the analysis of ligand/receptor binding (18), DNA quantitation (19), and DNA hybridization (20)(21)(22). Recently, we reported the first investigation of photoelectrochemical oxidation of various nucleic acids on ruthenium tris(bipyridine)-functionalized nanocrystalline SnO 2 electrodes and found the reaction sensitive to the DNA structure (23).…”