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(er)) between the working solution and the biosensor surface, recorded by the redox probe K(3)[Fe(CN)(6)]/K(4)[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. (C) 2011 Elsevier B.V. All rights reserved.