Sensitive Detection of BRCA1 Gene Based on Target Proximity Induced Quenching of the Fluorescence of Copper Nanoclusters

The mutations of breast cancer susceptibility gene 1 (BRCA1) play an important role in inherited breast cancers. Thus, the sensitive assay of the BRCA1 gene is extremely important for disease diagnosis and human health. Herein, a fast, sensitive and selective assay technique has been constructed based on fluorescent copper nanoclusters (CuNCs). The CuNCs were successfully formed with poly(AT-TA) double stranded DNA (dsDNA) as template. In the absence of the target, a strong red emission was observed under 365 nm ultraviolet (UV) lamp and a big fluorescence response was obtained. However, in the presence of BRCA1 gene, there was only weak red emission and a low response signal was produced because of the target-proximity induced quenching of the fluorescence of CuNCs. The linear range for the BRCA1 gene assay was 2-600 nM, and the limit of detection was 2 nM. The assay technique showed good selectivity, good stability and satisfactory recoveries for the detection of BRCA1 gene in diluted serum samples. Moreover, by integrating a UV lamp and a smartphone, the fluorescence sensor would be transferred to a microfluidic chip, providing a prospective application in point-of-care for monitoring breast cancer risk.