Self-cascade reaction triggered colorimetric detection of choline in triple-negative breast cancer

Achieving a simple process, detailed information, and visual response for cancer diagnosis and treatment is desirable but challenging. Herein, we develop a self-cascade system-triggered colorimetric array for the sensitive detection of choline, a promising biomarker in triple-negative breast cancer (TNBC). The system utilizes a ChOx-Ce³⁺ probe, where ChOx catalyzes the oxidation of target choline to betaine, generating H₂O₂, which then in situ reacts with Ce³⁺ to form a CeO₂ nanozyme. This nanozyme exhibits robust oxidase (OXD)-like activity, oxidizing tetramethylbenzidine (TMB) to oxTMB, resulting in a visible color change that correlates with choline concentration. The self-triggered cascade mechanism significantly simplifies the detection process by eliminating the need for expensive materials and complex equipment. Additionally, it enhances the selectivity, resistance to protein interference, and long-term stability of the probe. The system demonstrated high accuracy in measuring choline concentrations in MDA-MB-231 cells and real samples, with recovery rates ranging from 97.4 % to 101 %. These results illustrate the potential of the self-cascade system-triggered colorimetric array for early TNBC detection and therapeutic monitoring, offering a cost-effective, user-friendly diagnostic tool for clinical applications.