Fiber optic SPR sensor based on MOF-808 sensitization for interaction detection of Coptisine and DNA G-quadruplex

To detect the degree of interaction between coptisine and different DNA G-quadruplexes (G4s) and screen its anti-cancer targets, this paper developed a highly sensitive fiber surface plasmon resonance (SPR) sensor using zirconium-based metal organic framework (MOF-808) nanomaterials and plastic coated multimode optical fiber, which solves the problems of background interference and low sensitivity in traditional fluorescence detection method. MOF-808 has the characteristic of high electron mobility, which increases the sensitivity of the sensor to 4869.03   nm/RIU and improves the performance by 107%. Meanwhile, thanks to the ultra-high specific surface area of MOF-808, coptisine is enriched on the sensor surface, providing more G4s binding sites, the detection limit for c-MYC Pu22 G4 is 11.15   nM. Three types of G4s were detected using the sensor, and the sensor showed a significant response to c-MYC Pu22 G4, indicating that coptisine has a strong targeting effect on Pu22 G4, which is consistent with the results of molecular docking simulation, confirming the effectiveness of the sensor as a drug target screening validation tool. This sensor exhibits good specificity, with no significant response to other substances such as double stranded DNA except for the substance being tested, and maintains excellent stability after long-term storage. This work provides a concept validation optical sensing platform for drug target screening.