A High Sensitivity and Anti-Scaling Surface Plasmon Resonance Sensor for Early Screening of Colorectal Cancer.

Early screening is essential for improving the prognosis of colorectal cancer (CRC), for which fecal occult blood testing (FOBT) remains one of the most widely adopted noninvasive screening approaches. However, conventional FOBT methods often exhibit insufficient sensitivity and limited reliability when handling complex fecal matrices, largely due to nonspecific fouling and cumbersome sample pretreatment procedures. Herein, we report a surface plasmon resonance biosensor integrating a self-assembled anti-fouling interface with DNA aptamer-mediated molecular recognition for sensitive hemoglobin detection in fecal samples. The engineered sensing surface exhibits high interfacial stability and resistance to nonspecific adsorption, enabling direct analysis of fecal samples without complicated pretreatment. The proposed platform achieved a detection limit of 1 nM and a diagnostic accuracy of 97.6%. This study demonstrates the feasibility of SPR-based hemoglobin detection in complex fecal samples using an antifouling sensing interface and highlights its potential as a promising optical biosensing strategy for noninvasive colorectal cancer screening.