Electrochemical sensor for vascular endothelial growth factor based on self-assembling DNA aptamer structure.

Developing vascular endothelial growth factor (VEGF) protein is essential for early cancer diagnosis and cancer treatment monitoring. This study presents the design and characterisation of an electrochemical sensor utilising a self-assembling DNA aptamer structure for the sensitive and selective detection of VEGF. The aptamer structure comprises three different parts of single-stranded DNA that are assembled prior to integration into the sensor. Polypyrrole (Ppy)-based layers were deposited onto screen-printed carbon electrodes (SPCEs) using an electrochemical deposition technique, followed by the entrapment of a self-assembled DNA aptamer structure within electrochemically formed Ppy matrix ((DNA aptamer)/Ppy). The response to the sensor toward VEGF was measured by the pulsed amperometric detection (PAD), highlighting the enhanced performance of DNA aptamer/Ppy configuration compared to bare Ppy. The sensor exhibited high sensitivity, achieving a limit of detection (LOD) of 0.21 nM for VEGF. The interaction behaviour between VEGF in the solution and the immobilise DNA aptamer/Ppy-based structure was analysed using Langmuir isotherm model. The developed electrochemical biosensor is promising for in vitro applications in early cancer diagnostics and treatment monitoring, enabling rapid screening of patient samples.