Preparation of fluorescent sensor array based on internal self-polymerizing imprinted Janus nanosheets and its application in determination of multiple metal ions and bisphenol A.

Internal self-imprinting is an ingenious way to achieve the combination of imprinting and Pickering emulsions. Herein, internal self-polymerizing imprinted Janus nanosheets for detecting bisphenol A (BPA) and multiple metal ions are reported. Janus composite hollow spheres were prepared by grafting an imprinted polymer onto vinyl groups after an emulsion interfacial self-organized sol-gel process. After crushing, the external surface is further modified with thiol groups (-SH) and fluorescence signal indicators. Janus silica nanosheets (J-MIPs/SH@QDs) with bispecific artificial receptors (-SH and molecularly imprinted sites) were designed to specifically identify BPA and 4 metal ions (Hg2+, Cu2+, Cr3+, Ag+). CdTe QDs with red and yellow emissions were incorporated into the J-MIPs/SH@QDs as fluorescent signal indicators. Due to the presence of molecularly imprinted sites, BPA can be recognized with high specificity, resulting in increased fluorescence intensity. The thiol groups and metal ions formed a chelated structure with the fluorescence intensity decreasing. Linear discriminant analysis (LDA) in SPSS software can be used to analyze these specific fluorescence responses to distinguish BPA and multiple metal ions. In conclusion, J-MIPs/SH@QDs exhibit sensitivity in multi-organic-inorganic analyte combinations. Its desegregation of innovative bispecific receptors creates a multitude of opportunities for the specific and effective detection of coexisting contaminants.