Colorimetric sensor modified with MXenes@MnCoZDH@Au composite nanomaterials for visualization of circulating tumor cells in lung cancer.

Circulating tumor cells (CTCs), as a critical biomarker for early diagnosis and real-time monitoring of tumor progression, play a significant role in early cancer diagnosis, treatment monitoring, and prognosis evaluation. However, existing CTCs detection methods are limited by low purity, long processing time, high cost, and insufficient specificity, making them inadequate for clinical needs. This study developed an ultrasensitive and visually detectable CTCs sensing platform. The platform integrates nucleic acid aptamer-functionalized dopamine-coated magnetic nanoparticles as capture probes for the specific isolation and enrichment of CTCs, and MXenes@MnCoZDH@Au NPs as signal-amplifying nanoprobes with exceptional peroxidase-like activity. The colorimetric sensing mechanism relies on the linear increase in absorbance with CTCs concentration, enabling quantitative detection. Under optimized experimental conditions, the sensor demonstrated a broad detection range of 10 to 106 cells/mL and an ultra-low 2 cells/mL detection limit. Compared to traditional methods, this detection approach exhibited high specificity, sensitivity, and reproducibility, highlighting its potential for clinical translation. This innovative method provides a reliable and practical tool for liquid biopsy-based cancer diagnostics, offering significant advancements in precision medicine.