Mimicking the light harvesting system for sensitive pattern recognition of monosaccharides

Boronate affinity-based indicator displacement assay is a promising approach to develop high performance saccharide sensors. However, it is difficult to improve the sensitivity of saccharide sensors in aqueous solutions due to the highly hydrophilic and hydromimetic nature of saccharides. Inspired by the fact that the natural photosynthesis system uses densely packed dyes with a high energy donor to acceptor ratio to improve the light harvesting efficiency, an enhanced FRET complex named 4Esculetin-BAAP was designed with four coumarin units as the energy donor and one porphyrin moiety as the acceptor. The desired sensor array 4EBSA was then readily constructed by simple dissolving complex 4Esculetin-BAAP in PBS solutions with three different pH values. With this light harvesting mimic strategy, sensor array 4EBSA was determined to be accurate and sensitive for pattern recognition of 7 kinds of monosaccharides in a wide concentration range in both PBS and even 10% serum. Moreover, 4EBSA was successfully applied for distinguishing glucose and its phosphorylated product in mixed form in serum samples with a sensitivity of 0.01 mM and visualized identification of unknown monosaccharide samples.