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

Highlights: → Vascular Entothelial Growth Factor Receptor-1 was used as a biorecognition element as a first time in the literature. → Electrochemical impedance spectroscopy, as a measurement principle was used for analysis of VEGF-R1/VEGF interaction as a first time. → A layer-by-layer immobilization procedure enhanced the sensibility of the biosensor. → The biosensor could detect vascular endothelial growth factor in the range of 100-600 femtogram mL-1. - Abstract: 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 (Ret) 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.