title: Exploiting Sub-threshold and above-threshold characteristics in a silver-enhanced gold nanoparticle based biochip.
abstract: Silver-enhanced labeling is a technique used in immunochromatographic assays for improving the sensitivity of pathogen detection. In this paper, we employ the silver enhancement approach for constructing a biomolecular transistor that uses a high-density interdigitated electrode to detect rabbit IgG. We show that the response of the biomolecular transistor comprises of: (a) a sub-threshold region where the conductance change is an exponential function of the enhancement time and; (b) an above-threshold region where the conductance change is a linear function with respect to the enhancement time. By exploiting both these regions of operation, it is shown that the silver enhancing time is a reliable indicator of the IgG concentration. The method provides a relatively straightforward alternative to biomolecular signal amplification techniques. The measured results using a biochip prototype fabricated in silicon show that 240 pg/mL rabbit IgG can be detected at the silver enhancing time of 42 min. Also, the biomolecular transistor is compatible with silicon based processing making it ideal for designing integrated CMOS biosensors.
authors: Department of Electrical and Computer Engineering, East Lansing, MI 48824, USA.
authors: Yang
authors: Y
authors: Liu
authors: Evangelyn
authors: E
authors: Alocilja
authors: Shantanu
authors: S
authors: Chakrabartty
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002845:Chromatography / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004566:Electrodes; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods; D049329:Nanostructures; D036103:Nanotechnology / Q000379:methods*; D011817:Rabbits; D012834:Silver / Q000737:chemistry*; D013997:Time Factors; D014173:Transistors, Electronic
chemical_list: D007074:Immunoglobulin G; D012834:Silver; D006046:Gold