Controlled release of DNA from carbon-paste microelectrodes

Potential control has been used to release DNA from the surface of carbon e lectrodes under physiological pH. The protocol relies on the electrostatic adsorption of dsDNA onto a pretreated carbon-paste microelectrode, followed by an on-demand electrostatic desorption at - 1.20 V (versus Ag \ AgCl). T he procedure represents a potentially attractive route for delivering the g enetic material to specific locations. Various parameters influencing the r elease of the surface-confined DNA into the solution are explored and optim ized in connection with square-wave voltammetric 'blocking' experiments, ad sorptive-transfer stripping potentiometry. and energy dispersive X-ray anal ysis (EDX). Prospects and challenges of using DNA-modified microelectrodes for carrying therapeutic genes are discussed. (C) 1999 Elsevier Science S.A . All rights reserved.