Design and characterization of a silver-enhanced gold nanoparticle-based biochip

Silver-enhanced labeling method that is employed in immunochromatographic assay provides an effective way of improving the sensitivity of detecting pathogens. In this paper, we apply the silver enhancement approach for providing signal amplification in conductimetric biochips which employ gold nanoparticles to bridge on a high-density microelectrode array for detecting gold nanoparticles. One of the measurement methods presented in this paper is the silver enhancing time that is shown to be an indicator of the concentration of gold nanoparticles. The method provides an alternative to existing detection methods and it is straightforward to achieve high-sensitivity in detection. The measured results presented in this paper are based on a high-density interdigital microelectrodes with a 4 mum gap where we show detection limits as low as 25 femtomolar.