Dual-film-modulated self-temperature-compensating SPR biosensor for high-precision DNA hybridization detection of a lung cancer gene

Currently, the high-precision quantification of disease-related complementary DNA (cDNA) remains difficult, owing to the complex procedures of existing nucleic acid detection methods and their susceptibility to temperature fluctuations. Therefore, a dual-film-modulated fiber-optic surface plasmon resonance (SPR) biosensor with self-temperature compensation was proposed in this work, enabling high-precision detection of cDNA concentration through real-time temperature readout for in-situ temperature correction to improve the controllability of the measurement process. A low-loss no-core fiber (NCF) was used as the sensing platform, with an Ag film as the SPR excitation layer. A CeF 3 film was introduced into the DNA channel to enhance the interfacial response, while a TiO 2 layer was introduced into the temperature channel to regulate the resonance band and enable thermal readout. Simulations verified the sensitization effect of CeF 3 and the resonance wavelength modulation effect of TiO 2 . Further single-channel calibration and cascaded tests showed that the two channels operated independently with negligible crosstalk. The experimental results demonstrated that, over a cDNA concentration range of 0-90 nM, the DNA probe exhibited a maximum sensitivity of 0.412 nm/nM, an average sensitivity of 0.294 nm/nM, and a limit of detection (LOD) of 1.62 nM. Compared with conventional single-layer Au/Ag fiber-optic SPR nucleic acid sensors, the proposed sensor, with the synergistic integration of a CeF 3 sensitization layer and temperature compensation, achieves more accurate DNA quantification and a more competitive LOD. Its low cost and streamlined fabrication process further enhance its value for large-scale deployment, underscoring its strong potential in biomedical applications such as disease monitoring.