AVS 50th International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI-WeP

Paper BI-WeP10
Surface Physico-Chemical Studies of Immobilised Oligonucleotides

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: P-C.T. Nguyen, University of South Australia
Authors: P-C.T. Nguyen, University of South Australia
S. Kumar, University of South Australia
M. DeNichilo, TGR BioSciences, Australia
N. Voelcker, Flinders University of South Australia
H.J. Griesser, University of South Australia
Correspondent: Click to Email
Single-stranded oligonucleotides can bind nucleic acid targets as well as other targets such as small molecules, peptides, proteins and cells. Compared to antibodies, the selectivity, specificity and affinity of oligonucleotides are equal and often superior. Thus, surface-immobilised oligonucleotides have become attractive choices as recognition elements in microarrays for high throughput, parallel and multidimensional analysis in biomedical diagnostics, and aptamers are increasingly replacing antibodies as molecular recognition elements. So far, most of the research involving oligonucleotide probes has focussed on end applications for the life sciences, with some work on fundamental aspects of surface immobilisation and target binding to immobilised oligonucleotides. In order to harness the apparent power of such arrays, a more detailed physical and chemical understanding is required, in addition to optimising the immobilisation process. Contributing factors include substrate, oligonucleotide structure, immobilisation chemistry and surface density of immobilised oligonucleotides. Our focus is to characterise and optimise the density of immobilised oligonucleotides, and measure hybridisation efficiency for a specific choice of substrate, oligonucleotide, and immobilisation chemistry. Glass and silicon are the most commonly used substrates but we are extending immobilisation to polymeric carriers. XPS, ToF SIMS and AFM are used to surface characterise the substrate and attached oligonucleotides. Using principles of surface science we study molecular interactions between oligonucleotide chains, and the effects that the structure and packing density of the oligonucleotide coating have on hybridisation, assessed by MALDI-ToF-MS. It is expected that oligonucleotide density will have a direct bearing on activity and steric availability for hybridisation.