Abstract: By combining hydrogel with the nucleic acid dye SYBR Green Ⅰ, we have engineered mannose-functionalized hydrogel for E.coli O157: H7 detection based on multivalent binding of Con A. In this method, the hydrogel was first synthesized using acrylamide, N,N-dimethylacrylamide and N-acryloxysuccinimide, employing ammonium persulfate(APS) as the catalyst and etramethylethylenediamine(TEMED) as the accelerator. Then, the mannose was conjugated to the surface of the prepared hydrogel. After preparing the functional hydrogel, the sample was incubated with the hydrogel for 1 h and then stained with a nucleic acid dye SYBR Green Ⅰ. Finally the labeled E.coli O157: H7 was determined by the fluorescence in vivo imaging. The detection of E.coli O157: H7 was successfully carried out in buffer and bacterial mixture, respectively. This assay allowed the detection of E.coli O157: H7 in PB buffer as low as 3.7×10¹ Cells/mL within 2 h.

Key words: Hydrogel, SYBR Green Ⅰ, E.coli O157: H7, In vivo fluorescence imaging