Fluorescence optical spectrally resolved sensor based on molecularly imprinted polymers and microfluidics

Molecularly imprinted polymers (MIPs) are synthetic receptors that can be synthesized for a variety of target molecules. One of their possible applications is in chemical sensors. In this article, a microfluidic measurement setup with immobilized MIPs with fluorescence detection is described. Fluorescence measurements were performed on MIP films specific for the fluorescence-labeled amino acid dansyl-L-phenylalanine. A conventional imprinting protocol with noncovalent interactions between the functional monomers and the template was used. We present the immobilization of the polymers on quartz substrates to form homogenous and stable films over at least six cycles of measurement and regeneration, and their use for microfluidic measurements in a spectrofluorometer. Furthermore, the design and buildup for a reproducible fluorescence measuring system is described. With this system, concentrations of 0.5 mu M of dansyl-L-phenylalanine could be detected with 3 sigma certainty which is 50 times more sensitive compared with the detection of dansyl-L-phenylalanine without MIPs under the same conditions. The binding kinetics indicates that binding is completed after 30min. Our results show that MIP films in combination with fluorescence detection and microfluidic devices can be a very sensitive tool for the detection of biologically relevant analytes.