Geometric optimisation of electrohydrodynamic fluid flows for enhanced biosensing

摘要

AbstractThe removal of non-specific binding on the sensor surface represents a major challenge for rapid and sensitive biosensing. The stimulation of an electrohydrodynamic (EHD) fluid flow in proximity to the biosensor surface can improve sensor performance. The EHD fluid flow is depending on the geometry of electrodes. Here, the effect of electrode diameter and spacing of asymmetric circular electrodes is investigated for the capability to stimulate fluid flow and capture model beads and protein biomarker. Six geometries with diameters of 30–1000μm and spacing of 200–1500μm were systematically studied. Capture of target beads in excess of non-target beads showed higher target bead capture with increase in electrode diameter. The target bead capture was 4× improved and displacement of non-target reduced by factor 2. The electrode with the highest bead capture was then used to establish an immunoassay for detection of novel cancer immunotherapy biomarker CD28 fortified in buffer and fetal bovine serum. The EHD parameters for optimal CD28 capture were different to the bead capture parameters. This indicated that, depending on the binding strength of target to affinity tag, the EHD parameters could be tailored to provide ideal capture conditions. The use of EHD significantly reduced the assay time by 92.4%, removed non-target binding by a factor of 3.5 compared to static incubation, and was sensitive to detect as low as 20pgmL?1CD28. In a proof-of-concept study, the potential of the EHD-assisted immunoassay for point of care application was demonstrated using a simple naked eye read-out.