A highly sensitive fluorescent turn-on biosensor for glycoproteins based on boronic acid functional polymer capped Mn-doped ZnS quantum dots.

A simple fluorescence turn-on sensor has been designed for the highly sensitive detection of glycoproteins on the basis of boronic acid functional polymer capped Mn-doped ZnS quantum dots (QDs@MPS@AAPBA). In the absence of glycoproteins, the fluorescence emission intensity of the QDs@MPS@AAPBA was relatively weaker due to the effective electronic transfer from the QDs to the boron moieties on its surface. While the glycoproteins were introduced into the system, an obvious fluorescence enhancement was observed. It was attributed to the boron moieties covalent binding glycans of the glycoproteins resulting in the electronic transfer process being inhibited. Under the optimal conditions, this fluorescent probe not only could be applied in a wide pH range of 5.0-9.0, but also the binding constants and detection limits of the QDs@MPS@AAPBA for horseradish peroxidase (HRP) and transferrin (TRF) were up to 7.23 × 106  M-1 , 1.53 × 107  M-1 and 1.44 × 10-10  M, 3.36 × 10-10  M, respectively. Finally, this proposed method has also been utilized for the TRF determination in serum without any complicated pretreatment and the recovery was in the range of 95.7%-103.0%. As a result, it is promising for application on the glycoproteins detection in complex biological samples.