Natural Fish Trap‐Like Nanocage for Label‐Free Capture of Circulating Tumor Cells

Nanomaterials have achieved several breakthroughs in the capture of circulating tumor cells (CTCs) over the past decades. However, artificial fabrication of label‐free nanomaterials used for high‐efficiency CTC capture is still a challenge. Through billions of years of evolution and natural selection, various complicated and precise hierarchical structures are developed. Here, a novel fish trap‐like “nanocage” structure derived from the natural Chrysanthemum pollen is reported and a nanocage‐featured film for the label‐free capture of CTCs and CTC clusters is constructed. The nanocage‐featured film effectively captures 92% rare cancer cells with a broad spectrum of cancer types, due to the synergistic effect of nanocage‐CTC filopodia matching, high contact area, and strong adhesion force between the cancer cells and the nanocage. Furthermore, the nanocage‐featured film successfully detects CTCs and CTC clusters in 2 or 4 mL blood taken from 21 cancer patients (stages I–IV) suffering from various types of cancers. This novel, abundant, and economical fish trap‐like “nanocage” may provide new perspectives for the application of natural nanomaterials in clinical CTC capture and analysis.