Immobilisation and synthesis of DNA on Si(111), nanocrystalline porous silicon and silicon nanoparticles

摘要

Oligonucletodies have been synthesized on hydrogen-terminated Si(111) and porous silicon using surface hydrosilation of difunctional molecules (w, ω-dimethoxytritylundecenol) to produce a monolayer bearing suitable reactive groups to allow automated solid-phase DNA synthesized on Si(111) undergo hybridisation at the surface and a straightforward electrochemical quantization of the amount of synthesized DNA and its hybrtidisation efficiency (47%) is possible using Ru(NH_3)_6~(3+) as a redox label. In the case of DNA synthesized in porous silicon, electron transfer (ET) between DNA and the underlying bulk semiconductor can be studied by cyclic votammetry, however the anisotropic diffusion inside the porous layer nd the large resistance of the porous silicon results in voltammograms for which thin-layer behaviour is not observed and the peak currents increase with the square root of scan rate. We interpret these voltammorams in terms of charge transport limitations in the layer of metal centres bound to the DNA inside the pores.