A portable sensing platform enabled by permanganate-peroxide coupling for time-resolved analysis of xanthine oxidase activity in circulating tumor cells
- Spectrochim Acta A Mol Biomol Spectrosc. 2026 Jun 25;363(Pt 1):128317. doi: 10.1016/j.saa.2026.128317.
- 1. School of Materials Science & Chemical Engineering, Ningbo University, Ningbo 315211, PR China; Hunan Provincial Key Laboratory of Cytochemistry, School of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China.
- 2. School of Materials Science & Chemical Engineering, Ningbo University, Ningbo 315211, PR China; Ningbo Huayi Ningchuang Intelligent Technology Co., Ltd., Ningbo 315100, PR China.
- 3. School of Materials Science & Chemical Engineering, Ningbo University, Ningbo 315211, PR China.
- 4. School of Materials Science & Chemical Engineering, Ningbo University, Ningbo 315211, PR China; State Key Laboratory of Chemo and Biosensing, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China; Ningbo Huayi Ningchuang Intelligent Technology Co., Ltd., Ningbo 315100, PR China. Electronic address: [email protected].
- 5. Department of Oncology, Tengzhou Central People's Hospital Affiliated Xuzhou Medical University, Tengzhou 277500, PR China. Electronic address: [email protected].
- 6. Hunan Provincial Key Laboratory of Cytochemistry, School of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, PR China.
Early Cancer diagnosis demands rapid, sensitive and portable approaches for detecting cellular metabolic activities. Herein, we construct a portable time-resolved biosensing platform for visual and quantitative detection of Xanthine Oxidase (XOD) activity in circulating tumor cells (CTCs) based on a permanganate-peroxide coupling mechanism. In this strategy, XOD catalyzes the oxidation of xanthine to uric acid, accompanied by the generation of hydrogen peroxide (H2O2). The as-produced H2O2 subsequently reduces potassium permanganate (KMnO4) under mildly acidic conditions, resulting in a rapid decrease in the characteristic absorption of Mn(VII) species and a visually distinguishable color transition from purplish red to light yellow within 60 s. Since the yield of H2O2 generated is directly related to enzymatic turnover, XOD activity can be quantitatively translated into optical and digital colorimetric signals. The reaction can be monitored spectroscopically through absorbance changes at 526 nm or analyzed using smartphone-based RGB extraction for instrument-free quantification. Under optimized conditions, the optical response shows a good linear correlation with the logarithm of XOD activity with a detection limit of 0.0039 U/L (S/N = 3). Cellular studies revealed elevated XOD activity in cancer-derived CTCs compared with normal cells, as well as significant responses to XOD inhibition and oxidative stress. This platform provides a simple and portable tool for cellular enzyme profiling and point-of-care Cancer diagnostics.