Characterization and Application of Controllable Local Chemical Changes Produced by Reagent Delivery from a Nanopipet
- 15 July 2008
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 130 (31), 10386-10393
- https://doi.org/10.1021/ja8022253
Abstract
We introduce a versatile method that allows local and repeatable delivery (or depletion) of any water-soluble reagent from a nanopipet in ionic solution to make localized controlled changes in reagent concentration at a surface. In this work, Na+ or OH− ions were dosed from the pipet using pulsed voltage-driven delivery. Total internal reflection fluorescence from CoroNa Green dye in the bath for Na+ ions or fluorescein in the bath for pH quantified the resulting changes in local surface concentration. These changes had a time response as short as 10 ms and a radius of 1−30 μm and depended on the diameter of the pipet used, the applied voltage, and the pipet−surface separation. After the pipet dosing was characterized in detail, two proof-of-concept experiments on single cells and single molecules were then performed. We demonstrated local control of the sodium-sensitive flagellar motor in single Escherichia coli chimera on the time scale of 1 s by dosing sodium and monitoring the rotation of a 1 μm diameter bead fixed to the flagellum. We also demonstrated triggered single-molecule unfolding by dosing acid from the pipet to locally melt individual molecules of duplex DNA, as observed using fluorescent resonance energy transfer.Keywords
This publication has 32 references indexed in Scilit:
- Nanopipette Delivery of Individual Molecules to Cellular Compartments for Single-Molecule Fluorescence TrackingBiophysical Journal, 2007
- Electrochemical attosyringeProceedings of the National Academy of Sciences, 2007
- Nonequivalence of Membrane Voltage and Ion-Gradient as Driving Forces for the Bacterial Flagellar Motor at Low LoadBiophysical Journal, 2007
- The maximum number of torque-generating units in the flagellar motor of Escherichia coli is at least 11Proceedings of the National Academy of Sciences, 2006
- Design and Fabrication of a Novel Microfluidic NanoprobeJournal of Microelectromechanical Systems, 2006
- The scanned nanopipette: a new tool for high resolution bioimaging and controlled deposition of biomoleculesPhysical Chemistry Chemical Physics, 2005
- Continuous perfusion microfluidic cell culture array for high-throughput cell-based assaysBiotechnology & Bioengineering, 2004
- An Addressable Antibody Nanoarray Produced on a Nanostructured SurfaceJournal of the American Chemical Society, 2004
- “Microcanals” for micropipette access to single cells in microfluidic environmentsLab on a Chip, 2004
- Spatial heterogeneity and function of voltage– and ligand–gated ion channels in retinal amacrine neuronsProceedings Of The Royal Society B-Biological Sciences, 1999