Bientropy-powered catalysis crosslinked ultrasensitive nanobiosensor for precise NIR light-regulated imaging of tumor...

Owing to the protease-free and hairpin DNA primers-free design of entropy-powered catalysis (EPC), nanobiosensors constructed from this amplification protocol show promising potential for detecting tumor biomarkers in live biosystems. Nevertheless, EPC's single-round signal enhancement and perpetual activation during bio-delivery severally restrict its sensitivity and precision in responding to low-concentration analytes. To overcome these restrictions, this study first links together fuel strands produced by two separate EPC modules, thus establishing an ultrasensitive nanobiosensor that implements an exceptional crosslinked bientropy-powered catalysis with more powerful two-round amplification capacity. Following that, one DNA segment is embedded with a photocleavable bond to block the analyte's recognition site, whereby a near-infrared light (NIR)-regulated strategy facilitated by upconversion luminescence is utilized to precisely activate the biosensing operation. Our conceptual proof is validated by determining  microRNA-21, a low-abundance biomarker inclined to be overexpressed in various malignant tumors. In addition to ultra-high sensitivity (with a remarkably low limit of detection of 32.44 fM) and satisfactory specificity (discriminating even single-nucleotide mutations) in buffered environments, this bientropy-powered catalysis crosslinked nanobiosensor enables reliable imaging assays in both live cells and animals, offering a potent toolbox for cancer diagnostics.