Cascaded confinement-encapsulated fluorescence nano-immunomachine for noninvasive urinary monitoring of bladder cancer.

Herein, we developed a one-pot fluorescence nano-immunomachine for ultrasensitive quantification of urinary bladder cancer-specific nuclear matrix protein 4 (BLCA-4), driven by cascaded confinement-mediated quantum dots encapsulation in DNA nanospheres.

Upon streptavidin-biotin-directed antibody functionalization, the resulting QDs@DNS@Ab platform specifically recognized BLCA-4, triggering localized structural disassembly and spontaneous fluorescence recovery.

This washing-free homogeneous assay was completed within 40 min, achieving a dynamic range of 10-5 × 10 4 ag/mL and a detection limit of 3.6 ag/mL.