Colorimetric detection of Gadidae species using probe-modified gold nanoparticles

Codfish is an essential part of the world's marine fishery resources. It contains several commercially important species. The aim of the present work is to develop a rapid codfish colorimetric detection system based on gold nanoparticles (AuNPs) and a specific probe targeting the 12S rDNA of Gadidae species. Three cod species from Gadidae family (Gadidae morhua, G. macrocephalus and Melanogrammus aeglefinus) were selected as the target species in this colorimetric detection system. No positive results were obtained when non-Gadidae samples challenged this system, indicating its high specificity. The detection limit of G. morhua, G. macrocephalus and M. aeglefinus was 2.2, 3.15 and 2.65 ng/mu L, respectively. Furthermore, 20 commercial cod samples were detected by this method, and the results were consistent with those of obtained by PCR and DNA sequencing. As the results were judged by the naked eye and detection performed in fast mode (less than 30 min), the 12S rDNA-probe-AuNPs system had strong applicability, and thus it would facilitate further advances in food species authentication.