Ovalbumin-coated gold nanoparticles with interesting colloidal stability for colorimetric detection of carbaryl in complex media.

Pesticide carbaryl can cause serious environmental pollution and its sensitive detection is of increasing interest. Gold nanoparticles (AuNPs) are classically colorimetric probes for detection of many analytes, but the instability in complex media limits their application. Here, Au@Ova NPs have been developed as a stable, effective, sensitive, and selective sensing system for colorimetric detection of carbaryl. Au@Ova NPs present unique and proper colloidal stability in various medias containing salt, small molecules, organic solvent (DMSO), and seawater, which are distinct from previous ones including citrate (or rhodamine B) capped AuNPs. Compared with Au@BSA NPs, Au@Ova NPs showed efficient responses to carbaryl by inhibiting acetylcholinesterase, with a linear concentration range between 0 and 25 μg/L and a detection limit of 0.25 μg/L. In addition, this nanoprobe also has good selectivity and can be applied in different real samples analysis, including fruit juice (tomato and apple) and real water samples (artificial urine and seawater).