Chapter II. Oligonucleotide immobilisation, characterisation and hybridisation detection on gold surfaces
Chapter II. Oligonucleotide immobilisation, characterisation and
hybridisation detection on gold surfaces
The goal of this thesis is to develop novel DNA analytical instruments in the form of DNA sensors
and arrays. As explained, the development of such devices passes through the following
a) Immobilisation of probes.
c) Transduction and hybridisation detection.
This chapter of the thesis describes the preliminary work that led to the choice of solutions for items
a) and c). To choose the immobilisation techniques used for arraying, item c) described in Chapters
III and IV, it was necessary to examine the different possible routes.
The initial strategy examined for probe immobilisation and hybridisation detection is summarised in
ordered immobilised probes and
Scheme II.1. Immobilisation and hybridisation strategy.
The configuration described in Scheme II.1 consists of orderly immobilised probes in a mixed
monolayer with redox polymers of controlled size. Upon hybridisation of the redox enzyme-labelled
target, and in the presence of substrate, the electrons produced are transferred to the electrode
surface thorough an electron hopping mechanism that is much more efficient than diffusional
electron transfer. This improved electron collection efficiency combined with the reagentless