A “turn-on” fluorescent receptor for detecting tyrosine phosphopeptide using the surface imprinting procedure and the epitope approach

A new strategy for the manufacture of a turn-on fluorescent molecularly imprinted polymer (CdTe/SiO2/MIP) receptor for detecting tyrosine phosphopeptide (pTyr peptide) was proposed. The receptor was prepared by the surface imprinting procedure and the epitope approach with silica-capped CdTe quantum dots (QDs) as core substrate and fluorescent signal, phenylphosphonic acid (PPA) as the dummy template, 1-[3-(trimethoxysilyl) propyl] urea as the functional monomer, and octyltrimethoxysilane as the cross-linker. The synthetic CdTe/SiO2/MIP was able to selectively capture the template PPA and corresponding target pTyr peptide with fluorescence enhancement via the special interaction between them and the recognition cavities. The receptor exhibited the linear fluorescence enhancement to pTyr peptide in the range of 0.5-35 μM, and the detection limit was 0.37 μM. The precision for five replicate detections of pTyr peptide at 20 μM was 2.60% (relative standard deviation). Combining the fluorescence property of the CdTe QDs with the merits of the surface imprinting technique and the epitope approach, the receptor not only owned high recognition site accessibility and good binding affinities for target pTyr peptide, but also improved the fluorescence selectivity of the CdTe QDs, as well revealed the feasibility of fabrication of a turn-on fluorescence probe using the surface imprinting procedure and the epitope approach.