A novel electrochemical immunosensor for the ultrasensitive detection of vascular endothelial growth factor based on MB@Cu-MOFs/MWCNTs composite

A novel proposal is introduced with an unlabeled electrochemical immunosensor for the detection of tumor broad-spectrum biomarker vascular endothelial growth factor (VEGF165) Copper-based metal organic frameworks (Cu MOFs)-carbon nanotubes (MWCNTs) were employed as its substrates, functionalized with methylene blue (MB) for signal enhancement. Cu-MOFs-MWCNTs nanocomposites were synthesized successfully via a solvothermal method and were then deposited on the surface of a glassy carbon electrode (GCE), with the addition of methylene blue to amplify the signal. Due to the expansive specific surface area provided by the carbon nanotubes and the amino groups facilitated by the metal–organic framework nanomaterials, the anti-VEGF165 monoclonal antibody was immobilized on the electrochemical immunosensor through covalent bonding, which could bind specifically to VEGF165, thereby causing a detectable change in the current. The developed immunosensor exhibited a linear detection range for VEGF165 spanning from 1 to 100,000 pg/ml, with the R² value of 0.997 by differential pulse voltammetry (DPV) method, and the limit of detection was as low as 0.9686. Additionally, the electrochemical immunosensor presented commendable selectivity, availability, and reproducibility, along with an effective capacity for detecting VEGF165 in clinical samples. Consequently, the immunosensor is expected to revolutionize early screening for VEGF165-related diseases, which offer a promising, cost-effective, and precise diagnostic tool for clinical utility.

Graphical Abstract