Highly Stable, Water-Soluble, Intrinsic Fluorescent Hybrid Scaffolds for Imaging and Biosensing

A synthetic method is proposed for the preparation of micrometer-sized hybrid materials in the form of highly stable, water-soluble, porous, and intrinsic fluorescent vaterites. This is an easy, cost-effective, and polymer-free synthetic method, that is, free of any supplementary complex synthetic or natural macromolecular stabilizers. This method uses a double decomposition reaction to introduce fluorescence as an intrinsic property into the vaterite scaffold, through either organic dyes or dihydrolipoic acid coated core/shell CdSe/ZnS quantum dots. The resulting hybrid scaffold has excellent brightness, photostability, thermal stability, and pH stability. Combined with a large loading surface offered by the vaterite scaffold and the ease of chemical functionalization provided by the water-soluble quantum dots, the obtained hybrid scaffolds show promise in biological applications. Fluorescence imaging and fluorescence-resonance-energy-transfer-based sensing of proteins based on these hybrid materials is illustrated with these hybrid materials at the single-particle level.