Tetrahedral DNA nanostructures, graphene and carbon nanodots-based electrochemiluminescent biosensor for BRCA1 gene mutation detection.

In this study, we present a novel electrochemiluminescent DNA biosensor designed for detecting breast cancer type 1 (BRCA1) gene mutations. The biosensor integrates graphene nanosheets (Graph-NS), tetrahedral DNA nanostructures (TDNs), and carbon nanodots (CNDs) to enhance sensitivity and specificity. Graph-NS are employed to structure the transducer and serve as a platform for DNA immobilization. TDNs are engineered with a BRCA1 gene-specific capture probe located at the apex (TDN-BRCA1), facilitating efficient biorecognition. Additionally, the basal vertices of TDNs are functionalized with amino groups, enabling their attachment to the CSPE/Graph-NS surface via amino-graphene interaction. This platform effectively identifies single-base mutations in the BRCA1 gene utilizing synthesized CNDs as a coreactant and [Ru(bpy)3]2+ as the luminophore through the coreactant pathway. The developed biosensor demonstrates exceptional sensitivity and can detect a single mutation in the BRCA1 gene. Furthermore, it has been successfully validated in real samples obtained from breast cancer patients, showcasing a remarkable detection limit of 1.41 aM.