Integrating DNA with semiconductor materials: Bio-inorganic hybrid devices

A method for the automated solid-phase synthesis of DNA on a semiconductor chip with the potential for photolithography to fabricate hybrid electronic-DNA devices was developed. The on-chip oligonucleotide synthetic quality was comparable to standard CPG supports as confirmed by HPLC and gel electrophoresis. Enzymatic manipulation of the immobilised ssDNA was possible by radiolabelling with T4 polynucleotide kinase. Spatial control, afforded by photolithography, was visualised by phosphorimaging radiolabelled dsDNA. The charge transfer properties of DNA were investigated by the association of Ru[(NH3)(6)](3+) with the phosphate backbone and by intercalation with redox active methylene blue. Additionally ferrocene modified nucleosides were incorporated into oligonucleotides to act as electronic mediators for charge transfer. Initial investigations into the effect of the redox group on the nucleobase indicated their potential for use as bioelectronic building blocks for incorporation into silicon based molecular systems.