Development of a polymer resin as an improved adhesion layer in molecularly imprinted polymer based biosensors

Abstract

Synthetic receptors, like molecularly imprinted polymers (MIPs), are interesting for bio(mimetic) sensors. MIPs have imprints with high affinity for their template molecule and, after immobilization on substrates, can be used as artificial receptors. For cheaper functionalized substrates, van Grinsven et al. fixated MIPs with polyvinyl chloride (PVC). However, there were several problems like detachment of MIP particles or adhesion of air. As alternative, a polymer resin with macro crosslinkers and photo-initiator that will form covalent bonds with the MIPs is proposed. First, reversible addition fragmentation transfer (RAFT) polymerization was done in flow with a bifunctional RAFT-agent. A more hydrophilic resin reduces the attachment of air bubbles, thus 2-Hydroxyethyl acrylate (2-HEA) was polymerized with a molecular weight of 2000 g·mol-1. Next, aminolysis and subsequent Michael addition yielded the (homotelechelic) vinyl functionalities, giving the polymer the capability to crosslink. Even though UV-Vis indicated that there was 30% unreacted RAFT agent, 90% was crosslinked with 1 mol% photo-initiator and exposure to 1 min to UV light. The thickness of the adhesion layer could be controlled with the concentration of the poly(2-HEA) and the rotation speed of the spincoater. Although it was difficult to quantify, optical microscopy pictures showed that the functionalized substrate had a minimal decrease of particles after exposure to a demi-water flow.