Special Issue Article

Nanoscale Research Letters

, Volume 5, Issue 3, pp 533-538

Open Access This content is freely available online to anyone, anywhere at any time.

Biomolecules Detection Using a Silver-Enhanced Gold Nanoparticle-Based Biochip

  • Yang LiuAffiliated withElectrical and Computer Engineering, Michigan State University Email author 
  • , Deng ZhangAffiliated withBiosystems and Agricultural Engineering, Michigan State University
  • , Evangelyn C. AlociljaAffiliated withBiosystems and Agricultural Engineering, Michigan State University
  • , Shantanu ChakrabarttyAffiliated withElectrical and Computer Engineering, Michigan State University

Abstract

Silver-enhanced labeling method has been employed in immunochromatographic assays for improving the sensitivity of detecting pathogens. In this paper, we apply the silver enhancement technique for biomolecular signal amplification in a gold nanoparticle-based conductimetric biochip. We show that the response of the silver-enhanced biochip comprises two distinct regions namely: (a) a sub-threshold region where conduction occurs due to electron hopping between silver islands and the electrolyte and (b) an above-threshold region where the conduction is due to a direct flow of electrons. These two regions are characterized by different conduction slopes, and we show that combining the information from both these regions can improve the sensitivity of the biochip. Results from fabricated prototypes show a dynamic range of more than 40 dB and with a detection limit less than 240 pg/mL. The fabrication of the biochip is compatible with standard complementary metal–oxide–semiconductor (CMOS) processes making it ideal for integration in next-generation CMOS biosensors.

Keywords

Gold nanoparticle Silver enhancement Biomolecules Biochip Biosensor