Sensitive Visual Detection of Breast Cancer Cells via a Dual-Receptor (Aptamer/Antibody) Lateral Flow Biosensor.

We report a novel dual-receptor lateral flow biosensor (LFB) for the rapid, sensitive, and visual detection of MCF-7 breast cancer cells as a model for circulating tumor cells (CTCs). The biosensor employs a MUC1-specific aptamer conjugated to colloidal gold nanoparticles as the detection probe and an anti-MUC1 antibody immobilized at the test line as the capture probe, forming a unique "aptamer-cell-antibody" sandwich complex upon target recognition. This design enables instrument-free, visual readout within minutes, achieving a detection limit of 675 cells. The assay also demonstrates robust performance in spiked human blood samples, highlighting its potential as a simple, cost-effective dual-mode point-of-care testing (POCT) platform. This platform supports both rapid visual screening and optional strip-reader-based quantification, making it suitable for early detection and monitoring of breast cancer CTCs.