Chorafas Foundation Award 2010 - Sivagnanam Venkataragavalu

"For the synergistic implementation of original concepts in physics, chemistry, biology, and engineering into Lab-on-a-Chip microsystems."

Microfluidic immunoassays based on self-assembled magnetic bead patterns and time-resolved luminescence detection.

Microfluidic bio-assays have emerged as the most privileged solutions and provide the basis for the realization of miniaturized bio-analytical systems and clinical diagnostic devices that are portable, user-friendly and cost-effective (Lab-on-a-chip). Two important steps that are implemented in a microfluidic bio-assay are: (a) the immobilization and/or patterning of target-specific bio-molecules on the surface of a microfluidic channel, for selectively capturing bio-targets like antigens or pathogens, followed by (b) sensitive detection of the bio-targets. In this thesis, we demonstrate microfluidic bio-assays based on novel methods for generating protein-patterns and on sensitive detection of the bio-targets.

First, we introduce a simple and fast method for creating protein micropatterns both on a bare substrate and in-situ inside a microfluidic channel, in a matter of minutes, through electrostatic self-assembly of pre-functionalized magnetic beads. Subsequently, we use patterned beads as assay substrates for performing on-chip bioassays. We demonstrate highly-sensitive full on-chip sandwich immunoassays for single and multi-analyte detection using beads as assay substrate. Finally, we demonstrate a rapid on-chip immuno-histo-chemical assay on breast cancer tissues. We use luminescent lanthanide probes in place of conventional fluorescent probes, as labels for detection antibodies, for sensitive detection and quantification of biomarkers. Our assay results fully agree with the clinical analyses outcome and hence this opens perspectives for a fully-integrated cancer detection platform for bedside diagnostics.