Nanozyme-Based Pump-free Microfluidic Chip for Colorectal\nCancer Diagnosis via Circulating Cancer Stem Cell Detection

Circulating\ncancer stem cells (CCSCs) are subpopulations of cancer\ncells with high tumorigenicity, chemoresistance, and metastatic potential,\nwhich are also major drivers of disease progression. Herein, to achieve\nthe prediction of tumor diagnosis and progression in colorectal cancer\n(CRC), a new, automated, and portable lateral displacement patterned\npump-free (LP) microfluidic chip (LP-chip) with the CoPt<sub>3</sub> nanozyme was established for CCSC capture and detection in peripheral\nblood and feces samples ex vivo. In this design, CoPt<sub>3</sub>@HA\nprobes with functions of magnetic separation and colorimetric signal\ntransduction by peroxidase-mimicking activity were applied for the\ncapture of CCSCs and signal output in clinical samples. The generated\ncolors of polydopamine (PDA) were quantifiable through the smartphone\nAPP and visualizable by the naked eye in the test line (T line) and\ncontrol line (C line) of the LP-chip. In the optimal experimental\nconditions, the CCSC concentration was sensitive to change in the\nrange 0–10<sup>5</sup> cells mL<sup>–1</sup>, with a\ndetection limit of 3 cells mL<sup>–1</sup> (S/N = 3). Preliminary\nstudies of clinical samples suggest that the platform has the potential\nfor prediction of colorectal cancer progression and poor prognosis.\nOverall, the LP-chip provides potential strategies for timely diagnosis,\ntherapeutic monitoring, and recurrence prediction to improve home-based\npatient care.