RESUMEN
For the rapid and sensitive detection of vascular endothelial growth factor 165 (VEGF165) in clinical blood samples, a microfluidic sensing chip that integrates a centrifugal separation pretreatment unit and a composite nanosensing film was proposed in this paper. An efficient sensing strategy and method was established. The blood sample was first separated and extracted by centrifugal force on the centrifugal microfluidic chip within 5 min after injection. The separated plasma can be automatically transferred through the designed microchannels to the detection area integrated electrodes for subsequent differential pulse voltammetric detection. The Au NPs/MCH/Apt2 sensing film was constructed on the surface of the Au working electrode. A sandwich sensing strategy based on "double aptamers" and "nanoprobe" for VEGF165 detection was established, by which the synthetic Apt1/PThi/Au NP nanoprobe was applied to capture VEGF165 in plasma and bind to the sensing film. By this method, the detection limit of VEGF165 in whole blood was 0.67 pg/mL and the linear range was between 1 pg and 10 ng, which met the needs of clinical VEGF165 detection. It was illustrated that the proposed methodology based on the centrifugal microfluidic chip had potential application prospects in the development of the point-of-care testing fields.