.Electrochemical Sensing of 8-Hydroxy-2′-deoxyguanosine with a Portable Cu Metal Hydroxide Organic Framework Saliva Kit: Toward At-Home Oral Cancer Monitoring

8-Hydroxy-2'-deoxyguanosine (8-OHdG) is an important biomarker for oxidative DNA damage and is closely linked to oral cancer diagnosis and preventive medicine. However, traditional detection methods remain limited by cost, complexity, and poor suitability for point-of-care testing (POCT). Herein, we report an electrochemical sensor based on a copper-modified metal hydroxide organic framework (Cu/MHOF) with high sensitivity and selectivity for 8-OHdG detection. The Cu/MHOF electrochemical sensor demonstrated excellent stability, selectivity, and sensitivity for 8-OHdG detection, achieving a wide linear detection range (10 nM to 100 μM) and a low detection limit of 7.51 nM. Furthermore, this sensor enabled accurate quantitative analysis of 8-OHdG in complex biological samples. Based on this, we developed a portable saliva kit, offering a novel and effective platform for the rapid and accurate quantification of salivary 8-OHdG. This work demonstrates a practical strategy toward non-invasive POCT-based early warning and health monitoring of oral cancer risk.