Anti-Biofouling Nanoporous Gold Electrodes for Biochemical Sensor Applications

Within the scope of traumatic brain injury research, the implications of radical oxygen species (ROS) have been a primary interest. The ability to monitor these species cannot only provide a window into the progression of resultant pathology but also assist in therapeutic intervention by detailing the associated ROS insult experienced by the afflicted patient. Formation of protein plaques and aggregates is also associated with traumatic brain injury. These can form a passivation layer on the sensor’s surface leading to bio-fouling, thus limiting or even nullifying the sensitivity.  The nano-scale ‘roughness’ of our nanoporous gold (NPG) electrode augments the effective surface area for conduction and is found resistant to bio-fouling. Likely, the proteins are excluded from entering pores due to the constriction of pore sizes, which significantly reduces the sites for protein deposition.  NPG and plain gold electrode (PG) were tested in bovine serum albumin and beta amyloid to assess relative biofouling resistivity. The cyclic voltammetry (CV) from BSA incubation shows promise for NPG while PG experiences rapid surface saturation and loss of sensitivity (fig.1). CV was also performed in phosphate buffered saline (PBS) with a well-known redox couple of potassium hexacyanoferrate (HCF). Comparison between the CV measures for each electrode shows the increased conductivity for NPG. The results implicate the dual benefits of using the NPG for electrodes for increased sensitivity and resistance to bio-fouling.