Fluorescence growth of self-polymerized fluorescence polydopamine for ratiometric visual detection of DA

In this work, a novel and facile ratiometric fluorescence probe was prepared for the visual detection of dopamine (DA). In this detection system, red-emission CdTe@SiO₂ (r-QDs@SiO₂) was used as steady core of the probe and inverse microemulsion method was applied to synthesize uniform r-QDs@SiO₂, this step could protect CdTe from contacting with human skin directly. Polydopamine (PDA) acted as response signal to detect DA, a very handy method which just combined polyethyleneimine (PEI) with DA together to synthesize PDA, this way for synthesis of PDA was much time-saving and non-toxic than any other methods. Differently from traditional analysis processes, the products of this experiment were also the analysis substances in final. Under optimum measurement conditions, the dual-emission ratiometric fluorescence probe was used for detections of DA in a concentration ranged from 10μM to 80μM with a detection limit of 0.12μM, with addition of DA the color of the probe changed from red to green watched by naked eyes. In addition, the developed probe was also used for detections of DA in human serum samples successfully. This study provides a simple, time-saving and non-toxic approach for detections of DA without the requirement of complex equipment.