A new challenge in biointerfacial science is the development of dynamic surfaces with the ability to adjust and tune the chemical functionality at the interface between the biological and nonbiological entities. This paper describes the fabrication of indium-tin oxide (ITO) electrodes and the design of a ligand that can be switched to enable selectively controlled interactions with DNA. The research was done by the Nanobiotechnology team at Tyndall Institute, Ireland.

The activities of the Nanobiotechnology team are focussed on using the design, fabrication and characterisation tools developed for the ICT industry to address challenges in biology. The main research theme is addressing the challenge of providing improved systems for genetic analysis through the development of both optical and magnetic sensor platforms. A second research theme, that is simultaneously the focus of the current publication, is addressing the development of dynamic substrates for selective attachment and release of biomolecules on electrically addressable substrates.

Tyndall undertakes strategic research that focuses on technology bottlenecks and challenges in photonics, nanotechnology, microtechnologies and at the ICT/Bio interface. Research groups provide the interface between the physical and electronic worlds and the most significant developments have occurred in this field when existing technology has been applied to novel or different applications.

Abstract and Full Title:

Selective Release of DNA from the Surface of Indium-Tin Oxide Thin Electrode Films Using Thiol-Disulfide Exchange Chemistry

A new challenge in biointerfacial science is the development of dynamic surfaces with the ability to adjust and tune the chemical functionality at the interface between the biological and nonbiological entities. In this paper we describe fabrication of indium-tin oxide (ITO) electrodes and the design of a ligand that can be switched to enable selectively controlled interactions with DNA. Tailoring the surface composition of the ITO electrode to optimize its optical and electrical properties was also studied. The surface attachment chemistry investigated utilizes thiol-disulfide exchange chemistry. This chemistry involved the covalent attachment of a thiol-functionalized silane anchor to a hydroxyl-activated ITO electrode surface. Subsequent reaction with 2-(2-pyridinyldithio)ethanamine hydrochloride formed the disulfide bridge and provided the terminal amine group, which facilitates addition of a cross-linker. DNA was then covalently bound to the cross-linker, and hybridization with the complementary Cy3-labeled target DNA was achieved. Selective release of the attached DNA was demonstrated by both chemical and electrical reduction of the disulfide bond. The surface chemistry was then recycled, and rehybridization of the target DNA was achieved. The ability to control specific release of biomolecules has applications for the development of novel biosensor platforms and a range of medical devices.

Source: Selective Release of DNA from the Surface of Indium-Tin Oxide Thin Electrode Films Using Thiol-Disulfide Exchange Chemistry; Moore, E.J., Curtin, M., Ionita, J., Maguire, A.R., Ceccone, G., Galvin, P.; Anal. Chem., 79 (5), 2050-2057, 2007. DOI: 10.1021/ac0618324 S0003-2700(06)01832-4; Web Release Date: January 25, 2007, Copyright © 2007 American Chemical Society