Facile synthesis and biosensing application of hybrid zinc nanoparticles.

Hybrid zinc nanoparticles were synthesized by adding thioglycolic acid (TGA) into a ZnO-particle synthesis procedure. Compared to the ZnO particles prepared without TGA, the hybrid nanoparticles are markedly different in their morphology, chemical composition, and growth kinetics. Moreover, they display colloidal stability and appropriate surface properties for bioconjugation. To demonstrate their biosensing application, the hybrid nanoparticles were conjugated and applied as biolabels or signal transducers in a sandwich immunoassay for mouse IgG. The immunoassay fluorescence signal was obtained by releasing zinc ions from these nanoparticle labels and further incubating the released zinc ions with zinc-sensitive fluorescence indicator Fluozin-3. The immunoassay presents a dynamic detection range from 10 pM to 1 nM.