DNA immobilization on high aspect ratio glassy carbon (GC-MEMS) microelectrodes for bionanoelectronics applications

Abstract

We present the immobilization of DNA on a high aspect-ratio glassy carbon microelectrodes patterned using standard photolithography techniques and fabricated from pyrolyzed negative-tone photosensitive polymer, and their subsequent electrical characterization as part of a new bionanoelectronics platform. The 3D glassy carbon microelectrode architecture introduced here consists of mainly high aspect-ratio microelectrode structures (>20 μm height) with amide bond between the carboxylated glassy carbon electrode and aminated ?-DNA bridge suspended between two electrodes. The use of these glassy carbon electrodes patterned through lithography and derived from the pyrolysis of negative-tone resist polymers (hence called GC-MEMS) as opposed to the commonly used metal electrodes offers advantages of an inert carbon electrode surface that is resistant to non-specific binding of salts--an issue that has plagued most ?-DNA attachment experiments reported in the literature. The results demonstrate the ability to immobilize DNA on the surface or generate a DNA bridge between to GC-MEMS electrodes using oxygen plasma functionalization and carbodiimide crosslinking with aminated oligonucleotides. We also discuss in detail (1) the effect of concentration of reactants, (2) pH of the crosslinking reaction, and (3) the use of electrokinetic mixing in promoting DNA attachment on this GC-MEMS platform.