Radoslaw Bombera's Thesis Defense : " Development of biochips for blood cell sorting"

Monday 5 Decembre 2011 at 2pm

Room B221 - 1st floor - Maison MINATEC

3, parvis Louis Néel 38054 Grenoble

Radoslaw BOMBERA (INAC/SPrAM/CREAB)  

Thesis supervisors: Thierry LIVACHE et Yoann ROUPIOZ

This PhD thesis is devoted to conception of a miniaturized system of biochip type able to perform a controlled capture and release of different populations of the blood cells (e.g. lymphocytes). The main objective of the project is to create a potential tool of research, especially in the field of immunology, and medical diagnostics as well, that could perform short-time analyses by using a small sample amount. The approach relies more precisely on fabrication of a DNA matrix and further immobilization of cells through a hybrid molecule composed of an IgG antibody covalently coupled with short oligonucleotide sequence. Synthesis of the conjugated product is developed and demonstrates functional assembly on the micro-platform. Lymphocytes are specifically addressed onto biochip surface and once they are captured, two independent strategies of selective release are proposed.  Therefore, immobilized cells are specifically detached either upon enzymatic cleavage of oligonucleotide substrate or physically desorbed by local heating and denaturation of double stranded DNA. The system makes use of Surface Plasmon Resonance Imaging (SPRi) to enable real time detection of different biomolecular phenomena in a label-free and high-throughput manner. Accessorily, a particular instrumental approach is developed in order to observe cell capture-release steps directly under optical microscopy. The biochip construction permits to extend its performance to many targets and may be further explored in terms of application to analysis of complex biological samples such as blood.

Mots clés: biochip, cell sorting, SPR imaging, biomolecule conjugation, restriction enzyme, photothermal effect