Iodide-Responsive Cu–Au Nanoparticle-Based Colorimetric Platform for Ultrasensitive Detection of Target Cancer Cells

Colorimetric analysis is promising in developing facile, fast, and point-of-care cancer diagnosis techniques, but the existing colorimetric cancer cell assays remain problematic because of dissatisfactory sensitivity as well as complex probe design or synthesis. To solve the problem, we here present a novel colorimetric analytical strategy based on iodide-responsive Cu–Au nanoparticles (Cu–Au NPs) combined with the iodide-catalyzed H2O2–TMB (3,3,5,5-tetramethylbenzidine) reaction system. In this strategy, bimetallic Cu–Au NPs prepared with an irregular shape and a diameter of ∼15 nm could chemically absorb iodide, thus indirectly inducing colorimetric signal variation of the H2O2–TMB system. By further utilizing its property of easy biomolecule modification, a versatile colorimetric platform was constructed for detection of any target that could cause the change of Cu–Au NPs concentration via molecular recognition. As proof of concept, an analysis of human leukemia CCRF-CEM cells was performed using aptam...