Single-Molecule Detection with Lightguiding Nanowires: Determination of Protein Concentration and Diffusivity in Supported Lipid Bilayers
Artikel i vetenskaplig tidskrift, 2019

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.

nanowires

supported lipid bilayer

Biosensing

microscopy

single molecule

waveguide

diffusivity

Författare

Damiano Verardo

Lunds universitet

Björn Agnarsson

Chalmers, Fysik, Biologisk fysik

Vladimir Zhdanov

Chalmers, Fysik, Biologisk fysik

Russian Academy of Sciences

Fredrik Höök

Chalmers, Fysik, Biologisk fysik

Heiner Linke

Lunds universitet

Nano Letters

1530-6984 (ISSN) 1530-6992 (eISSN)

Vol. 19 9 6182-6191

Ämneskategorier

Fysikalisk kemi

Bioteknisk apparatteknik

Biofysik

DOI

10.1021/acs.nanolett.9b02226

PubMed

31369284

Mer information

Senast uppdaterat

2019-11-11