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Portrait of Heiner Linke; Photo: Kennet Ruona

Heiner Linke

Professor, Deputy dean at Faculty of Engineering, LTH

Portrait of Heiner Linke; Photo: Kennet Ruona

Single-Molecule Detection with Lightguiding Nanowires : Determination of Protein Concentration and Diffusivity in Supported Lipid Bilayers

Author

  • Damiano Verardo
  • Björn Agnarsson
  • Vladimir P. Zhdanov
  • Fredrik Höök
  • Heiner Linke

Summary, in English

Determining the surface concentration and diffusivity of cell-membrane-bound molecules is central to the understanding of numerous important biochemical processes taking place at cell membranes. Here we use the high aspect ratio and lightguiding properties of semiconductor nanowires (NWs) to detect the presence of single freely diffusing proteins bound to a lipid bilayer covering the NW surface. Simultaneous observation of light-emission dynamics of hundreds of individual NWs occurring on the time scale of only a few seconds is interpreted using analytical models and employed to determine both surface concentration and diffusivity of cholera toxin subunit B (CTxB) bound to GM1 gangliosides in supported lipid bilayer (SLB) at surface concentrations down to below one CTxB per μm2. In particular, a decrease in diffusivity was observed with increasing GM1 content in the SLB, suggesting increasing multivalent binding of CTxB to GM1. The lightguiding capability of the NWs makes the method compatible with conventional epifluorescence microscopy, and it is shown to work well for both photostable and photosensitive dyes. These features make the concept an interesting complement to existing techniques for studying the diffusivity of low-abundance cell-membrane-bound molecules, expanding the rapidly growing use of semiconductor NWs in various bioanalytical sensor applications and live cell studies.

Department/s

  • Solid State Physics
  • NanoLund

Publishing year

2019

Language

English

Pages

6182-6191

Publication/Series

Nano Letters

Volume

19

Issue

9

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Biological Sciences

Keywords

  • Biosensing
  • diffusivity
  • microscopy
  • nanowires
  • single molecule
  • supported lipid bilayer
  • waveguide

Status

Published

ISBN/ISSN/Other

  • ISSN: 1530-6984