2420 © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim small 2010, 6, No. 21, 2420–2426 wileyonlinelibrary.com full papers 1. Introduction Nanofluidic systems provide promising solutions for detection, sensing and biomolecular handling in single mol- ecule environments due to their extremely small confine- ment. Many research groups have demonstrated distinctive Rapid Prototyping of Nanofluidic Systems Using Size-Reduced Electrospun Nanofibers for Biomolecular Analysis Seung-min Park, Yun Suk Huh, Kylan Szeto, Daniel J. Joe, Jun Kameoka, Geoffrey W. Coates, Joshua B. Edel, David Erickson, and Harold G. Craighead* bioanalytical applications such as a biomolecular pre- concentrator, [1,2] nanogap detector [3,4] and single biomol- ecule manipulation device [5,6] with continued work towards practical analytical applications. [7–10] However, important issues remain, especially concerning the intricacy of the fabrication processes involved, which limit rapid prototyping DOI: 10.1002/smll.201000884 Dr. S-m. Park, [+] K. Szeto, Prof. H. G. Craighead School of Applied and Engineering Physics Cornell University 205 Clark Hall, Ithaca, NY 14853, USA E-mail: hgc1@cornell.edu Dr. Y. S. Huh, [++] Prof. D. Erickson Sibley School of Mechanical and Aerospace Engineering Cornell University Ithaca, NY 14853, USA D. J. Joe School of Electrical and Computer Engineering Cornell University Ithaca, NY 14853, USA Biomolecular transport in nanofluidic confinement offers various means to investigate the behavior of biomolecules in their native aqueous environments, and to develop tools for diverse single-molecule manipulations. Recently, a number of simple nanofluidic fabrication techniques has been demonstrated that utilize electrospun nanofibers as a backbone structure. These techniques are limited by the arbitrary dimension of the resulting nanochannels due to the random nature of electrospinning. Here, a new method for fabricating nanofluidic systems from size-reduced electrospun nanofibers is reported and demonstrated. As it is demonstrated, this method uses the scanned electrospinning technique for generation of oriented sacrificial nanofibers and exposes these nanofibers to harsh, but isotropic etching/heating environments to reduce their cross-sectional dimension. The creation of various nanofluidic systems as small as 20 nm is demonstrated, and practical examples of single biomolecular handling, such as DNA elongation in nanochannels and fluorescence correlation spectroscopic analysis of biomolecules passing through nanochannels, are provided. Nanofibers Prof. J. Kameoka Department of Electrical and Computer Engineering Texas A&M University, USA Prof. G. W. Coates Department of Chemistry and Chemical Biology Cornell University Ithaca, NY 14853, USA Dr. J. B. Edel Department of Chemistry and Institute of Biomedical Engineering Imperial College London SW7 2AZ, London, UK [ +] Current Address: Biomolecular Nanotechnology Center, Berkeley Sensor and Actuator Center, Department of Bioengineering, University of California at Berkeley, Berkeley, CA 94720, USA [ ++] Current Address: Division of Materials Science, Korea Basic Science Institute, Daejeon, 305-333, South Korea