Recently, MIAO Peng's group in Suzhou Institute of Biomedical Engineering and Technology (SIBET) of the Chinese Academy of Sciences has proposed a novel fluorescent method to simultaneously detect alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) based on a polydopamine nanosphere@silver nanocluster (PDAN@AgNC) system.

The levels of CEA and AFP in serum are found to be related to the occurrence of many types of cancers. Simultaneous detection of multiplex targets plays an important role in the diagnosis of carcinoma. There is an increasing need to establish a convenient and stable analytical tool for screening multiplex tumor markers.

In this research, the PDAN@AgNC system was developed for fluorescence quenching and recovery in response of CEA and AFP. DNA-templated AgNCs with different emissions were synthesized which also contained aptamer sequences against AFP and CEA, respectively.

In the absence of targets, AgNCs were adsorbed on the surface of the PDAN, the fluorescence emissions were thus quenched. Nevertheless, CEA and AFP interacted with corresponding aptamers, and AgNCs could be released from the surface of the PDAN. The recovered fluorescence could be used to indicate the concentration of the tumor markers.

Experimental results showed that this fluorescence detection system could achieve nanomolar detection sensitivity. This method also possessed merits of simplicity, enzyme/antibody-free nature, low cost and convenient operation. Therefore, it had great potential to be used in biomedical research studies and clinical diagnosis.

This paper entitled "Polydopamine nanosphere@silver nanoclusters for fluorescent detection of multiplex tumor markers" has been published in Nanoscale.

This work was supported by the National Natural Science Foundation of China, the Scientific Research Instrument Developing Project of the Chinese Academy of Sciences, and the Science and Technology Program of Suzhou.

Figure 1. Scheme of the PDAN@AgNC based fluorescent biosensor for the detection of multiplex tumor markers. (Image by JIANG Yiting) 

Figure 2. TEM images PDANs and AgNCs. (Image by JIANG Yiting) 

Figure 3. Fluorescence emission spectra of the PDAN@(A-AgNCs/C-AgNCs) for simultaneous detection of AFP and CEA with (A) the same and (C) different concentrations. (B) and (D) show calibration curves reflecting the relationship between FL peak intensities and the concentrations of the two tumor markers. (Image by JIANG Yiting)