We accurately detect 1–10 cells among 100 cancer cells of the breast, lungs, or cervix in 1 mL blood samples. Here, we report efficient detection and collection of cancer cells in blood samples by combining stem cell antigen (CD44)-specific immunosilica particles and immunofluorescent quantum dots with spectrally and temporally resolved single-photon counting. Liquid biopsy of circulating tumor cells (CTCs) has recently become a painless and noninvasive tool for obtaining carcinoma cell samples for molecular profiling. Amid the COVID-19 pandemic, cancer continues to be the most devastating disease worldwide.
