Optical sensing of phenylalanine in urine via extraction with magnetic molecularly imprinted poly(ethylene-co-vinyl alcohol) nanoparticles.

Incorporation of superparamagnetic nanoparticles into molecularly imprinted polymers (MIPs) is useful for both bioseparations and for concentration and sensing of biomedically relevant target molecules in physiological fluids, through the application of a magnetic field. In this study, we combined the separation and concentration of a target (phenylalanine) in urine, using magnetic molecularly imprinted polymeric composite nanoparticles, with optical sensing, to improve assay sensitivity. This target is important as a catecholamine precursor, and as an important amino acid constituent of proteins.