title: Liquid glass electrodes for nanofluidics.
abstract: Nanofluidic devices make use of molecular-level forces and phenomena to increase their density, speed and accuracy. However, fabrication is challenging, because dissimilar materials need to be integrated in three dimensions with nanoscale precision. Here, we report a three-dimensional nanoscale liquid glass electrode made from monolithic substrates without conductive materials by femtosecond-laser nanomachining. The electrode consists of a nanochannel terminating at a nanoscale glass tip that becomes a conductor in the presence of high electric fields through dielectric breakdown, and returns to being an insulator when this field is removed. This reversibility relies on control of nanoampere breakdown currents and extremely fast heat dissipation at nanoscale volumes. We use the nanoscale liquid glass electrode to fabricate a nano-injector that includes an electrokinetic pump, 4 microm across with 0.6 microm channels, which is capable of producing well-controlled flow rates below 1 fl s(-1). The electrode can be integrated easily into other nanodevices and fluidic systems, including actuators and sensors.
authors.affiliation: Department of Mechanical Engineering, POSTECH, Pohang, 790-784, South Korea.
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Lee
authors.forename: Ran
authors.initials: R
authors.lastname: An
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Hunt
mesh_terms: D055664:Electrochemical Techniques; D004566:Electrodes; D004912:Erythrocytes; D005898:Glass / Q000737:chemistry*; D006801:Humans; D046210:Microfluidic Analytical Techniques; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods
references.citation: Nat Nanotechnol. 2007 Feb;2(2):121-8
references.pmid: 18654231
references.citation: Anal Chem. 2003 Aug 15;75(16):4265-71
references.pmid: 14632145
references.citation: J Am Chem Soc. 2008 Jul 9;130(27):8614-6
references.pmid: 18549214
references.citation: Anal Chem. 2003 Feb 15;75(4):947-52
references.pmid: 12622389
references.citation: Anal Chem. 2005 Aug 15;77(16):5083-8
references.pmid: 16097742
references.citation: Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):5856-61
references.pmid: 15071188
references.citation: J Chromatogr A. 2003 Mar 21;990(1-2):11-22
references.pmid: 12685579
references.citation: Biomicrofluidics. 2009 Jan 02;3(1):12001
references.pmid: 19693382
references.citation: Anal Chem. 2002 Aug 1;74(15):3690-7
references.pmid: 12175155
references.citation: Nature. 2001 Sep 13;413(6852):226-30
references.pmid: 11557992
references.citation: Nano Lett. 2005 Sep;5(9):1638-42
references.pmid: 16159198
references.citation: Electrophoresis. 2003 Jan;24(1-2):185-92
references.pmid: 12652590
references.citation: Anal Chem. 2003 Jan 15;75(2):306-12
references.pmid: 12553766
references.citation: Anal Chem. 2005 Jul 15;77(14):4293-9
references.pmid: 16013838
references.citation: Anal Chem. 1998 Jul 1;70(13):2459-67
references.pmid: 21644766
references.citation: Lab Chip. 2003 Nov;3(4):281-6
references.pmid: 15007459