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

We propose a model for the formation of these two types of particles and briefly discuss the prospects to extend our solid-phase synthesis on porous silicon to allow the facile synthesis of luminescent Si nanocrystals bearing DNA or other biomolecules

L. H. Lie

2003

Scholarcy highlights

  • Oligonucleotides have been synthesized on hydrogen-terminated Si(111) and porous silicon using surface hydrosilation of difunctional molecules to produce a monolayer bearing suitable reactive groups to allow automated solid-phase DNA synthesis
  • In the case of DNA synthesized in porous silicon, electron transfer between DNA and the underlying bulk semiconductor can be studied by cyclic voltammetry, the anisotropic diffusion inside the porous layer and 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
  • Further evidence for this interpretation has been obtained using scanning electrochemical microscopy to study the charge transport between redox species in films of DNA synthesized on Si(111) surfaces that are in contact with an aqueous phase
  • Electrochemical quantitation of the DNA is not possible in this situation, we have been able to obtain independent determinations using radioassay based on 32P or UV/VIS spectrophotometry of dimethoxytrityl cation cleaved from the porous layer
  • This can be interpreted in terms of the specific surface area of the porous silicon layers since the hybridisation efficiencies obtained by comparing DMT+ cleaved from sequences synthesized on the surface and from complementary sequences after hybridisation were relatively insensitive to the current density used to prepare the layers
  • We propose a model for the formation of these two types of particles and briefly discuss the prospects to extend our solid-phase synthesis on porous silicon to allow the facile synthesis of luminescent Si nanocrystals bearing DNA or other biomolecules
  • For reproduction of material from all other RSC journals: - Reproduced by permission of The Royal Society of Chemistry

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