A novel, ultra sensible biosensor built by layer-by-layer covalent attachment of a receptor for diagnosis of tumor growth

In the presented research, a novel, ultra sensitive biosensor for the impedimetric detection of vascular endothelial growth factor (VEGF) is introduced. The human vascular endothelial growth factor receptor 1 (VEGF-R1, Flt-1) was used as a biorecognition element for the first time. The immobilization of VEGF-R1 on glassy carbon electrodes was carried out using layer-by-layer covalent attachment of VEGF-R1. The electrochemical properties of the layers constructed on the electrodes were characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The differences in electron transfer resistance (R_et) between the working solution and the biosensor surface, recorded by the redox probe K₃[Fe(CN)₆]/K₄[Fe(CN)₆], confirmed the binding of VEGF to VEGF-R1. The new biosensor allowed a detection limit of 100 fg mL⁻¹ with a linear range of 100–600 fg mL⁻¹ to be obtained. The biosensor also exhibited good repeatability (with a correlation coefficient of 1.95%), and reproducibility.