基于Fe3O4和Man-CQDs纳米探针双标记模式定量检测沙门氏菌

Salmonella is a common intestinal pathogenic bacteria, which has been threatening the safety of human life. It is important to establish a rapid and sensitive method for the detection of salmonella.In the paper, citric acid was used as carbon source for preparing fluorescent CQDs. Due to the obtained CQDs was rich in carboxyl group on the surface, Man-CQDs was synthesized by immobilizing 4-Aminopheny-l-α-D-mannopyanoside on surface of CQDs via covalent bond. Man-Fe3O4 was obtain by the same way. In the mixed solution, Salmonella was selectively captured,and Salmonella-Man-Fe3O4 complexes was isolated by exerting external magnetic field. Morever, the captured Salmonella was labeld?by Man-CQDs, Salmonella labeled double recognition was test by fluorescence spectroscopy. The results show that there is a good linear relationship between the logarithm of the concentration of Salmonella and the corresponding fluorescence value, linear equation IFL=217.2Log(c)-758.8(R2=0.9578), the linear range is 104cfu - mL-1 - 107cfu - mL-1, the detection limit is 5×103 CFU - mL-1. A method for detection of Salmonella bacteria based on the magnetic nano-probes was developed.