Selective room temperature phosphorescence sensing of target protein using Mn-doped ZnS QDs-embedded molecularly imprinted polymer

The direct correlation between disease states and protein levels makes the sensitive, convenient, and precise detection of proteins the focus of scientific research. This paper demonstrates a new strategy for producing phosphorescent molecularly imprinted polymer (MIP) for specific recognition of a target protein. The technique provides surface graft imprinting in aqueous solutions using vinyl modified Mn-doped ZnS QDs as supports, methacrylic acid and acrylamide as functional monomers, and bovine hemoglobin as a template. The QDs act as antennae for recognition signal amplification and optical readout, and the MIP shell provides analyte selectivity and prevents interfering molecules from coming into contact with the QDs. The small particle sizes and the nontoxicity of the MIP-QDs composites allows for good dispersibility and stability in an aqueous solution. Under optimal conditions, good linear correlations were obtained for bovine hemoglobin over the concentration range from 1.0×10⁻⁷ to 5.0×10⁻⁶ mol L⁻¹ and with recoveries of 96.7-103.8% and 92.6-94.2% for urine and serum samples, respectively. The long lifetime of the MIP-QDs composites phosphorescence avoids interference due to autofluorescence and scattering of the biomatrix, facilitating composites' application for detection of bovine hemoglobin in biological fluids.