Dual-labelled immunoassay with goldmag nanoparticles and quantum dots for quantification of casein in milk

Abstract

A dual-labelled immunoassay using goldmag nanoparticles (GMNPs) and CdTe quantum dots (QDs) was applied for the quantification of casein in milk. In this method, anti-casein monoclonal antibody bound to GMNPs was used as capture probe, and the anti-casein polyclonal antibody, labelled with CdTe QDs, was employed as detection probe. This dual-labelled immunoassay was optimized and applied in the testing of casein content of three brands of commercial milks. The results showed a good linear tendency between casein concentrations and fluorescent intensities in the range of 4.617-289.9 ng/mL, and the half inhibition concentration (IC 50 ) was 36.59 ng/mL. Besides, the recovery rates of this developed immunoassay were in accordance with those in traditional enzyme-linked immunosorbent assay for rapid detection of casein content in commercial milks. It suggested that this dual-labelled immunoassay was reliable, and could provide important theoretical value and practical significance in the identification and quantification of milk allergens. ARTICLE HISTORY

Aptamer-Based Fluorescent Biosensor for the Rapid and Sensitive Detection of Allergens in Food Matrices

“…The difference in structure and content of casein in human milk and cow's milk is the main cause of casein sensitization. A study has shown that about 65% of sufferers are allergic to casein [86]. Whey protein accounts for 20% of milk protein, and the main allergenic components are α-lactalbumin and β-lactoglobulin [87].…”