Glucose-selective polymer

Wang has employed the template approach using monomer 84 to prepare a fluorescent polymer with enhanced selectivity towards D-fructose [161,162]. Appleton has used a similar approach using monomer 85 to prepare a D-glucose selective polymer [77]. The Appleton polymer clearly shows the value of the imprinting technique. Here, the selectivity of the monomer for D-fructose over D-glucose has been reversed in the polymeric form. 

James and co-workers have developed polymer sensors by grafting a solution based D-glucose selective receptor 27d to a polymer support [78]. The major difference between the polymer-bound system 86 and solution-based system 27d is the D-glucose selectivity, which drops for polymer 86 (whereas the selectivity with other saccharides is similar to those observed for compound 27d). However, the polymeric system still has enhanced D-glucose selectivity (nine times) over the monoboronic acid model compound. The reduced binding of 86 for D-glucose has been attributed to the proximity of the receptor to the polymer backbone. 

Application of transition metal hexacyanoferrates for development of biosensors was first announced by our group in 1994 [118]. The goal was to substitute platinum as the most commonly used hydrogen peroxide transducer for Prussian blue-modified electrode. The enzyme glucose oxidase was immobilized on the top of the transducer in the polymer (Nation) membrane. The resulting biosensor showed advantageous characteristics of both sensitivity and selectivity in the presence of commonly tested reductants, such as ascorbate and paracetamol. 

An early example of an MIP-QCM sensor was a glucose monitoring system by Malitesta et al. (1999). A glucose imprinted poly(o-phenylenediamine) polymer was electrosynthesized on the sensor surface. This QCM sensor showed selectivity for glucose over other compounds such as ascorbic acid, paracetamol, cysteine, and fructose at physiologically relevant millimolar concentrations. A unique QCM sensor for detection of yeast was reported by Dickert and coworkers (Dickert et al. 2001 Dickert and Hayden 2002). Yeast cells were imprinted in a sol-gel matrix on the surface of the transducer. The MIP-coated sensor was able to measure yeast cell concentrations in situ and in complex media. A QCM sensor coated with a thin permeable MIP film was developed for the determination of L-menthol in the liquid phase (Percival et al. 2001). The MIP-QCM sensor displayed good selectivity and good sensitivity with a detection limit of 200 ppb (Fig. 15.7). The sensor also displayed excellent enantioselectivity and was able to easily differentiate the l- and D-enantiomers of menthol. 

Trichloroacetimidates are widely used in oligosaccharide syntheses as anomeric leaving groups. They can also be applied under solid-phase conditions when the acceptor is attached to the resin. Glucose is bound to the solid support by functionalization of the anomeric center with a propanedithiol linker [2]. (l,6)-Glycosylation is achieved by selective deprotection of the primary hydroxyl group and coupling of the obtained polymer-bound acceptor 1... 

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