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Abstract :
[en] Molecularly imprinted polymers (MIPs) are synthetic polymer materials with artificially
created recognition sites able to selectively rebind a target molecule in preference to other
closely-related molecules. MIPs are usually produced by copolymerization of functional
monomer and a high fraction of cross-linking agents in the presence of a template molecule,
leading to highly cross-linked networks with rigid cavities being the complementary in shape,
size and functionalities of the template. Owing to this particularity, MIPs found many
applications and more particularly as sorbent for solid phase extraction in the pharmaceutical
and biological field. However, in the frame of drug discovery from natural extract, rigidity of
the designed cavities will hamper the discovery of new active compounds. Therefore, good
compromise between rigidity and flexibility should be found to allow template analog
detection.
This work aims at developing MIPs presenting enough flexibility to selectively bind structural
template analogs without losing template selectivity. To this end, quercetin imprinted
polymers (Qu MIPs) were prepared by copolymerizing acrylamide (functional monomer) with
EGDMA cross-linker and a small quantity of PEG-methacrylate (Mn = 300 g.mol-1), the
small PEG tail being here to bring enough deformations to the MIP cavity. Bulk
polymerization (BP), precipitation polymerization (PP) and suspension polymerization (SP)
were investigated to obtain optimal chromatographic materials. Particle size and shape were
characterized by scanning electron microscopy (SEM) and/or transmission electron
microscopy. Successful imprinting was confirmed by SPE since the retention of quercetin
appeared distinctly superior on MIPs than on NIPs (produced in the absence of the template).
HPLC analyses highlighted also the ability of MIPs to retain more quercetin analogues while
non-analogs were eluted on the same way on MIPs and NIPs columns. Finally, the
polymerization process was found to impact a lot the final selectivity of MIPs and best results
were obtained by suspension polymerization.
