title: Enhancing Electrochemical Detection by Scaling Solid State Nanogaps.
abstract: The ability to quickly and inexpensively fabricate planar solid state nanogaps has enabled research to be effectively performed on devices down to just a few nanometers. Here, nanofabricated electrode pairs with electrode-to-electrode spacings of <4, 6 and 20 nm are utilized for monitoring an electroactive molecules, dopamine, in ionic solution. The results show a several order of magnitude enhancement of the electrochemical signal, collected current, for the solid state nanogaps with 6 nm electrode-electrode spacings as compared to traditional microelectrodes. The data from the <4 nm and 20 nm solid state nanogaps verify that this enhancement is due to cycling of the redox molecules in the confined geometry of the nanogap. In addition the data collected for the <4 nm nanogap emphasizes and reinforces that scaling does have limits and that as device sizes move to the few nanometer scale, the influence of a molecule's size and other physical properties becomes increasingly important and can eventually dominate the generated signals.
authors.affiliation: Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh NC 27695.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: McCarty
authors.forename: Benjamin
authors.initials: B
authors.lastname: Moody
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Zachek
references.citation: Anal Chem. 1996 Jul 1;68(13):2084-9
references.pmid: 9027223
references.citation: Analyst. 2007 Apr;132(4):365-70
references.pmid: 17554417
references.citation: Anal Bioanal Chem. 2009 May;394(2):447-56
references.pmid: 19125239
references.citation: Science. 2001 Feb 9;291(5506):1019-20
references.pmid: 11161210
references.citation: Science. 1995 Feb 10;267(5199):871-4
references.pmid: 17813918
references.citation: Trends Neurosci. 2004 May;27(5):270-7
references.pmid: 15111009
references.citation: Talanta. 2004 Jul 8;63(4):1053-9
references.pmid: 18969533
references.citation: Appl Phys Lett. 2009 Mar 23;94(12):122104
references.pmid: 23696694
references.citation: Proc Natl Acad Sci U S A. 2005 Jul 19;102(29):10023-8
references.pmid: 16006505
references.citation: J Neurosci. 2004 Jan 14;24(2):303-9
references.pmid: 14724228
references.citation: J Electroanal Chem (Lausanne). 2008;614(1-2):113-120
references.pmid: 19319208
references.citation: Anal Chem. 1996 Sep 15;68(18):3180-6
references.pmid: 8797378
references.citation: Anal Chem. 2004 Oct 1;76(19):5697-704
references.pmid: 15456288
references.citation: Anal Chem. 1999 Jul 15;71(14):2782-9
references.pmid: 10424168
references.citation: Anal Chem. 2008 Feb 15;80(4):972-7
references.pmid: 18193890
references.citation: J Neurochem. 2003 Jan;84(2):373-81
references.pmid: 12558999
references.citation: Langmuir. 2007 Jan 16;23(2):638-48
references.pmid: 17209615