Molecularly imprinted two-dimensional photonic hydrogel for chiral recognition of L-Glutamic acid

Glutamic acid (Glu) plays an important role in controlling and regulating the central nervous system and serves as a biomarker for liver diseases. The present detection methods need sophisticated instruments, professional personnel, or are confined for practical applications due to the issues of chiral recognition and the susceptible sensing signal. Here, an L-Glu imprinted two-dimensional photonic hydrogel (Glu-MIPH) was constructed to achieve highly selective, accurate and facile detection of L-Glu by combining molecular imprinting and twodimensional photonic crystal (2DPC) hydrogel sensing technology. Upon exposure to L-Glu solution, the hydrogel shrinks because L-Glu enters the nanocavities that are like L-Glu in shape, size and binding sites, then forms hydrogen bonds with the amide and carboxyl groups in the hydrogel and increases the crosslinking density. The contracted hydrogel decreases the particle spacing of the 2DPC embedded in the Glu-MIPH, displaying an increase in the Debye diffraction ring diameter. The spacing decrement is linear when L-Glu changes in 1-10 mu M and 20-100 mu M. The limit of detection is found to be 0.96 mu M. The Glu-MIPH demonstrates excellent selectivity, anti-interference, reproducibility for L-Glu, and has been successfully used to determine L-Glu in soy sauce, providing an alternate strategy for chiral recognition of amino acids.