Abstract

Surface Functionalization Strategies for the Design of Thermoplastic Microfluidic Devices for New Analytical Diagnostics

Fanny d'Orlyé, Associate Professor, Chimie ParisTech, Unité de Technologies Chimiques et Biologiques pour la Santé

Cyclic olefin copolymer (COC) and fluoropolymer (Dyneon THV) are emerging materials attractive for the conception of microfluidic chips thanks to their UV-visible transparency and high resistance to aggressive solvents. We propose to develop new analytical microsystems using these polymers for trace quantitation in complex matrices. This involves the immobilization of selective ligands in a confined zone of the microchannel for target extraction and preconcentration. This integrated pretreatment step will be followed inside the microdevice by electrokinetic separation and on-line detection. This requires new surface treatments for chemically inert COC and Dyneon to modify the microfluidic system at two scales: (1) on the entire surface to control surface properties and fluid flows during electrokinetic separation, or (2) locally to immobilize selective ligands (aptamers) on restricted areas for target extraction. For global modification, a plasma-induced immobilization of brominated derivatives allowed further ligand immobilization through alkyne-azide “click” chemistry reaction. For local ligand immobilization, we developed an original electrochemical strategy on Dyneon THV microchannel. Local electrochemical carbonization followed by covalent linkage of ligands (aptamers) through “click” reaction leads to immobilization zones in the 50 micrometer range.