Sensor Applications Based On Molecularly Imprinted Polymers Prepared By Solid Phase Approach

Molecularly imprinted polymers (MIPs) have received considerable attention due to their low cost preparation, robustness and high stability. MIP nanoparticles (MIP NPs) offer significant advantages over bulk materials as they have a high surface-to-volume ratio resulting in enhanced chemical reactivity and binding kinetics. This thesis demonstrates the use of MIP NPs as sensing elements for the direct detection of analyte in biomimetic sensors. Chapter two describes a potentiometric sensor for cocaine based on MIP NPs. MIP NPs were prepared in water and organic solvents. Imprinted polymers produced in organic solvent using acrylamide as a functional monomer demonstrated high yield and affinity. Nanoparticles were incorporated within a PVC matrix which was then used to prepare an ion-selective membrane integrated with a potentiometric transducer. The developed sensor has successfully detected cocaine in blood serum in the range of concentrations 1 x10-9-1x10-3 M. Chapter three describes a QCR sensor based on MIP NPs to detect gram-negative bacterial quorum signalling molecules N-Acyl homoserine lactone (AHL). The affinity of MIP NPs was analysed using BIAcore 3000. After that, a novel acoustic technique based on Fixed Frequency Drive (FFD) combined with MIPs was used for the detection of AHL exploiting N-hexanoyl-L-homoserine lactone (C6 HSL) as a model molecule. The FFD technique enabled sensitive, label-free, rapid and real-time detection of C6 HSL in spiked PBS solution with a minimum quantification limit 1x10-3 M. Chapter four describes an electrochemical sensor based on an electroactive molecularly imprinted polymer (EMIP) containing an electroactive mediator. Different polymerisation strategies were used to fabricate the EMIP for three different targets: HSL, trypsin and glucose. Differential pulse voltammetry (DPV) was used to evaluate the selectivity and sensitivity of EMIP towards these targets. The detection limits for these targets were 0.3x10-9, 0.22x10-9 and 0.13x10-6 M respectively.