Folding integrated all-paper photoelectrochemical immunoassay using annealed ZnO for point-of-care detection of ferritin.

Source: PubMed, NCBI / U.S. National Library of Medicine

Achieving early and sensitive detection of esophageal cancer-related biomarkers in community healthcare settings is of great significance for the early screening, diagnosis, and intervention of diseases. This work developed a paper-based photoelectrochemical (PEC) immunosensing array loaded with thermally annealed ZnO nanocatalysts for the sensitive detection of ferritin, a biomarker of ferroptosis associated with the esophageal cancer, in community healthcare settings. A paper-based three-electrode system was mass-produced using screen printing technology, and thermally annealed ZnO nanocatalysts with excellent resistance to photo-corrosion were obtained and loaded onto the working electrode surface. The opposite region of the electrode was modified with ferritin-specific antibodies to enable target-specific capture and signal conversion. A one-step folding strategy was employed to directionally transfer the catalytic product, ascorbic acid, to the electrode interface, where it efficiently converts the biological signal into a photoelectric signal under excitation from a handheld flashlight. This sensor array demonstrated a wide linear detection range (0.1 - 50 ng mL) and a low detection limit (0.038 ng mL), while offering the advantages of low cost (1.0 $ per test), portability, and mass producibility. This work provides a rapid and reliable diagnostic tool for the early screening of esophageal cancer-related diseases in community settings.