Molecularly imprinted polymers-based novel optical biosensor for the detection of cancer marker lysozyme

Lysozyme (Lyz) is well known as a kind of cancer marker, and the detection of Lyz is essential for early diagnosis cancers and further effective treatment. Herein, this work firstly proposed a synthesized strategy of silica cross-linked molecularly imprinted polymers and we applied it for construction of fluorescent biosensor determining Lyz. At pH 6.8, the negative charges on the surface of the 3-Mercaptopropionic acid modified CdTe quantum dots (MPA-CdTe QDs) and the positive charges of Lyz electrostatically combined, which reduces the degree of surface defects and improves the stability of the QDs. Therefore, the fluorescence intensity of the CdTe QDs coated molecularly imprinted polymer (MIP@CdTe QDs) would increase after combing Lyz. And the fluorescence intensity of MIP@CdTe QDs would decrease when Lyz leave the imprinting site of MIP@CdTe QDs. After a series of optimized experiments in detail, the linear range was at concentration of 10–120 μg/mL, and the limit of detection was 3.2 μg/mL. The MIP@CdTe QDs were successfully applied to detect the Lyz in human serum and chicken egg white, giving recoveries ranging from 95.6% to 99.2%.