Title: Molecularly-imprinted surface bound nanofilaments as synthetic recognition layers.
Author: Fanny VANDEVELDE
National thesis number: 2007COMP1703
- Molecularly imprinted polymers (MIPs) represent a novel type of bioinspired materials that mimic the behaviour of natural antibodies, enzymes or receptors, while exhibiting far greater stability than their natural counterparts. Their usefulness has no more to be demonstrated for applications in bioanalytical chemistry such as immunoassays or biosensors. Coupling silicon-based microfabricated structures with MIPs used as sensitive layer appears particularly interesting since that combines the binding selectivity of the MIPs with a high-sensitivity and high-resolution transduction mechanism eliminating the need of labelling. We describe, in this study, a MIP-based label-free sensing system for the herbicide 2,4-dicWorophenoxyacetic acid (2,4-0) is validated using piezoelectric micro-membranes working in dynamic mode. The MIP precursor solution containing the template molecule 2,4-0 and a corresponding non-imprinted polymer (NIP) precursor solution without 2,4-0 as a control were deposited on the membranes using a specific cantilever array-based microspotting technique. We describe the preparation of nanostructured molecularly-imprinted surfaces using nanomolding on porous alumina. This approach produces snrface-bound nanofilaments, which greatly increases the surface area of the material and should result in a faster mass transfer compared to porous films. Two different approaches were chosen : imprinting of the bulk filaments, and imprinting of the filament surface. For the bulk and surface imprinting, we used the blocking drug propranolol and the dye fluorescein, respectively, as the target molecules (the imprinting templates). Rebinding studies performed with the imprinted surfaces and with non-imprinted control surfaces revealed a specific recognition of the templates and thus the existence of selective molecularly imprinted binding sites.