Electrochemical immunosensor for the predictive cancer biomarker SLFN11 using reduced graphene oxide/MIL-101(Cr)-NH₂ composite

SLFN11 is a predictive cancer biomarker essential for identifying tumors that are sensitive to DNA-damaging agents, facilitating more personalized and effective treatment approaches. Detecting this biomarker can guide therapeutic decisions and improve outcomes for cancer patients. However, existing detection methods for SLFN11 are complex and require advanced techniques. In this study, we introduce the first immunosensor designed for on-site detection of SLFN11. An advanced electrochemical immunosensor platform utilizing a composite of graphene oxide (GO) and chromium-based metal organic framework (MIL-101 (Cr)-NH₂) was developed. The integration of GO and MIL-101(Cr)-NH₂ was characterized through FT-IR, XRD, SEM, and XPS, affirming the formation of the composite. The subsequent electrochemical reduction to rGO/MIL-101(Cr)-NH₂ significantly improved the electrochemical performance and stability. A glutaraldehyde cross-linker was then utilized to attach the SLFN11-specific antibody to the amine groups of the MOF-modified electrodes. This led to the development of rapid, sensitive, portable, and cost-effective immunosensor for SLFN11 at concentrations as low as 8.9 pg/mL which holds promise for early cancer diagnosis. High specificity was achieved, with minimal cross-reactivity observed with other cancer biomarkers such as pepsinogen I, claudin 18.2 and Programmed cell death protein 1. Demonstrating practical applicability, the electrochemical immunosensor validated by commercial ELISA kit showed successful detection in serum samples with high recovery rates and reproducibility. This research highlights the potential of rGO/MOFs composites in electrochemical biosensors developments for early cancer diagnostics and personalized medicine.