Surface plasmon resonance sensors using molecularly imprinted polymers for sorbent assay of theophylline, caffeine, and xanthine

Abstract

A sensor system based on the optical phenomenon of surface plasmon resonance (SPR), which employs either photothermal deflection spectroscopy (PDS) or a photodiode array (PDA) for detection, was developed to use molecularly imprinted (MI) polymethacrylic acid - ethylene glycol dimethacrylates (PMAA-EDMA) as the sensing element. The MI polymers were first processed by Soxhlet extraction to remove the print molecules (theophylline, caffeine, and xanthine), yielding the specific anti-polymers. Each anti-polymer was layered over a silver film to serve as the analysis surface for the molecularly imprinted sorbent assay (MIA) of one target drug. This surface was exposed for 60 min to an aqueous standard drug solution, dried in air, and the uptake of the print molecule into the anti-polymer was monitored by shifts in the SPR angle θ r (and hence the SPR-PDS signal measured at constant θ ). The linear dynamic range of the MIA was found to extend up to 6 mg/mL, with a concentration detection limit estimated at 0.4 mg/mL for theophylline in aqueous solution. A cross-reactivity study of the anti-theophylline and anti-caffeine polymers, using eight other drugs structurally similar to theophylline and caffeine, showed none or very slight shifts in θ r. This implies that the anti-polymers were selective only for their original print molecules and had no affinity for the other drug molecules. Similar molecular recognition characteristics were observed for the anti-xanthine polymer.Key words: surface plasmon resonance, molecular imprinting, theophylline, caffeine, xanthine, sensor.

Design of nano- and micro-structured molecule-responsive hydrogels

“…On the other hand, molecular imprinting has attracted considerable attention as a useful technique for creating synthetic hosts containing molecular recognition sites 26,27 . Lai and coworkers reported pioneering work on SPR sensor chips with molecularly imprinted layers prepared using theophylline, caffeine, and xanthine as template molecules 28 . The SPR sensor chips with molecularly imprinted layers showed the highly selective detection of the target molecules.…”

Surface plasmon resonance studies on molecularly imprinted films

“…10,[15][16][17][18][19]30 The combination of molecularly imprinted materials (MIPS) and SPR spectroscopy is a potent analytical method for the detection of a given target molecule 19,[31][32][33]35,36 like that of MIPS and surface-enhanced Raman scattering, 37 that of MIPS and conductimetry, 38 that of MIPS and fluorescence, 39 that of MIPS and quartz crystal microbalance (QCM), [40][41][42] and so forth.…”

Molecular Fingerprints Using Imprinting Techniques

“…The MIPs are suitable for almost any kind of transducer, but piezoelectric sensors [23,24] (quartz crystal microbalance (QCM), surface acoustic wave (SAW)), surface plasmon resonance (SPR), [25] and luminescence sensors [26] (fiber optics or optoelectronic devices) are amongst the most universal and sensitive. These sensors are easy to integrate into electronic circuits and are therefore ªtrulyº miniaturizable.…”