2-D Vanadium Disulfide nanosheets assisted ultrasensitive, rapid, and label-free electrochemical quantification of cancer biomarker (MMP-2).

Cancer is one of the most tormenting global health burdens reporting high mortality and morbidity worldwide. Matrix metalloproteinase 2 (MMP-2) protein has elevated expression for most types of cancers, including prostate and breast cancer. Therefore, accurate and specific detection of MMP-2 biomarker is crucial for screening, treatment, and prognosis of related cancer. In this work, we have proposed a label-free electrochemical biosensor for the detection of MMP-2 protein. This biosensor was fabricated using hydrothermally synthesized vanadium disulfide (VS2) nanosheets with monoclonal anti-MMP2 antibodies biofunctionalized using a suitable linker. The VS2 nanomaterials were synthesized hydrothermally at different reaction temperatures (140, 160, 180 and 200) generating different morphologies from a 3-D bulk cubic structure at 140C to 2-D nanosheets at 200C. Owing to the advantages of 2-D VS2 nanosheets with high surface-to-volume ratio, excellent electrochemical response and high antibody loading possibility, it was selected for fabricating an MMP-2 specific biosensor. The antibody-antigen binding event is analyzed by recording electrochemical impedance spectroscopy (EIS) signals for different target MMP-2 protein concentrations. The sensitivity and lower limit of detection (LOD) were 7.272 (R/R)(ng/mL)-1cm-2 and 0.138 fg/mL, respectively in 10 mM phosphate buffer saline (PBS) for this proposed sensor. Further, interference studies were also performed which demonstrates the sensor to be highly selective against non-specific target proteins. This 2-D VS2 nanosheet-based electrochemical biosensor is a sensitive, cost-effective, accurate, and selective solution for cancer diagnosis.