Miniaturized Multiplex Label-Free Electronic Chip for Rapid Nucleic Acid Analysis Based on Carbon Nanotube Nanoelectrode Arrays

Abstract

Background:Reducing cost and time is the major concern in clinical diagnostics, particularly in molecular diagnostics. Miniaturization technologies have been recognized as promising solutions to provide low-cost microchips for diagnostics. With the recent advancement in nanotechnologies, it is possible to further improve detection sensitivity and simplify sample preparation by incorporating nanoscale elements in diagnostics devices. A fusion of micro-and nanotechnologies with biology has great potential for the development of low-cost disposable chips for rapid molecular analysis that can be carried out with simple handheld devices. Approach: Vertically aligned multiwalled carbon nanotubes (MWNTs) are fabricated on predeposited microelectrode pads and encapsulated in SiO 2 dielectrics with only the very end exposed at the surface to form an inlaid nanoelectrode array (NEA). The NEA is used to collect the electrochemical signal associated with the target molecules binding to the probe molecules, which are covalently attached to the end of the MWNTs. Content: A 3 ؋ 3 microelectrode array is presented to demonstrate the miniaturization and multiplexing capability. A randomly distributed MWNT NEA is fabricated on each microelectrode pad. Selective functionalization of the MWNT end with a specific oligonucleotide probe and passivation of the SiO 2 surface with ethylene glycol moieties are discussed. Ru(bpy) 2؉ -mediator-amplified guanine oxidation is used to directly measure the electrochemical signal associated with target molecules.

Vertically aligned carbon nanofiber nanoelectrode arrays: electrochemical etching and electrode reusability

“…1-3 Integration of variety of 1-D nanomaterials such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), 4, 5 silicon and other nanowires, 8, 9 with microelectrode arrays 10 or interdigitated arrays 11,12 and associated micro/nanofluidics can provide interesting lab-on-a-chip devices for point-of-care-testing applications. Carbon nanostructures such as CNTs and CNFs have been explored extensively for sensor applications due to their unique advantages such as enhanced electrical properties, higher chemical and mechanical stability, rapid electrode kinetics, easy surface functionalization, modification and probe attachment for specific biotargets.…”

Colloidal gold nanoparticles: a novel nanoparticle platform for developing multifunctional tumor‐targeted drug delivery vectors

“…For example, the miniaturization of diagnostics may not only provide clinicians with a more complete snapshot of blood chemistries, hormones, and growth factors in both normal and diseases states, but may also allow them to track the efficacy of putative therapeutics [Koehne et al, 2004]. Complementing its diagnostic advances, bionanotechnology also holds the promise of increasing the therapeutic index, a measure of the benefit/risk ratio, of current cancer therapies, as a prime example [Papisov, 1998;Moghimi and Patel, 1998;Woodle, 1998;Nafayasu et al, 1999;Maruyama et al, 1999].…”

Vertically Aligned Carbon Nanofibers: Interconnecting Solid State Electronics with Biosystems

“…To solve this problem, the SiO 2 surface needs to be passivated with protective moieties such as ethylene glycol, which is known to resist the nonspecific adsorption of biomolecules, and develop a scheme to selectively attach probes at the VACNF ends. 22 First, the freshly polished VACNF array is thoroughly cleaned by immersing the sample in 1.0 M HNO 3 for 15 min, which forms -OH groups on the SiO 2 surface. The sample is then immersed in an solution of 3-aminopropyltriethyoxysilane (8 g/L in ethanol, Aldrich) for 20 min to produce a primary amine terminated SiO 2 surface.…”