Colorimetric Biosensor for Early Detection of MUC1-Positive Cells Using Aptamer-Conjugated Plasmonic Gold Nanostars

The development of highly sensitive and specific diagnostic tools is crucial for the early detection and treatment of cancer. Aptamer-conjugated gold nanostars (AuNSs) offer a promising approach, combining molecular recognition with unique plasmonic properties for targeted detection of cancer biomarkers. In this study, we developed a colorimetric biosensor based on S2.2 aptamer-conjugated AuNSs for detecting mucin 1 (MUC1)-positive lung and breast cancer cells. The detection principle hinges on the specific binding of the S2.2 aptamer to the MUC1 protein, which is overexpressed on the surface of cancer cells. Upon binding of the S2.2 aptamer to mucin 1 (MUC1), the aggregation of AuNSs occurs, leading to concentration-dependent changes in their optical properties that are visible as a color change. The biosensor demonstrated high sensitivity, detecting MUC1-positive cells within a range of 500 to 20 000 cells per well, with a detection limit of 450 cells per well in water and serum media. The simplicity of the colorimetric response, coupled with label-free detection, highlights the potential of this biosensor for point-of-care applications.