A chiral assembly of gold nanoparticle trimer-based biosensors for ultrasensitive detection of the major allergen tropomyosin in shellfish.

A biosensor based on a chiral assembly of polymer of gold nanoparticle (AuNP) trimers was developed for the detection and quantification of the major shellfish allergen tropomyosin (TROP). TROP and anti-TROP monoclonal antibodies (mAb) were immobilized on 20 nm and 30 nm 16-mercaptohexadecanoic acid (16-MHDA) functionalized AuNPs to assemble a trimer, which has a Circular dichroism (CD) signal. The free TROP from samples was quantified as an inhibitor for the formation of the AuNP trimer. The AuNP trimer-based biosensor allowed for the selective determination of TROP in the range of 0.1-15 ng mL-1 with the limit of detection (LOD) of 21 pg mL-1 (S/N = 3) and the limit of quantitation (LOQ) of 70 pg mL-1 (S/N = 10). The use of a AuNP trimer-based biosensor with simple sample preparation functions with specificity and accuracy; this highlights its applicability for the detection of allergens in shellfish products, related products and their production lines. Furthermore, based on the less conserved sequences of TROP in phylogenetically different species, this biosensor is currently being used to identify the adulteration of shellfish products using TROP as biomarker.