High-resolution imaging of a cell-attached nanointerface using a gold-nanoparticle two-dimensional sheet

Shihomi Masuda,Satoru Kidoaki,Yuhki Yanase,Thasaneeya Kuboki,Kaoru Tamada,Sou Ryuzaki,Eiji Usukura,Pangpang Wang,Koichi Okamoto

doi:10.1038/s41598-017-04000-4

Shihomi Masuda, Satoru Kidoaki + Show 7 more

Open Access

https://doi.org/10.1038/s41598-017-04000-4

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Abstract

This paper proposes a simple, effective, non-scanning method for the visualization of a cell-attached nanointerface. The method uses localized surface plasmon resonance (LSPR) excited homogeneously on a two-dimensional (2D) self-assembled gold-nanoparticle sheet. The LSPR of the gold-nanoparticle sheet provides high-contrast interfacial images due to the confined light within a region a few tens of nanometers from the particles and the enhancement of fluorescence. Test experiments on rat basophilic leukemia (RBL-2H3) cells with fluorescence-labeled actin filaments revealed high axial and lateral resolution even under a regular epifluorescence microscope, which produced higher quality images than those captured under a total internal reflection fluorescence (TIRF) microscope. This non-scanning-type, high-resolution imaging method will be an effective tool for monitoring interfacial phenomena that exhibit relatively rapid reaction kinetics in various cellular and molecular dynamics.

Highlights

Fluorescence microscopy has been a key technology in the field of cell biology for the past several decades
The light confined by localized surface plasmon resonance (LSPR) detects fluorescence molecules in a region of only a few tens of nanometers at the interface[19, 20], which creates notably high ‘axially’ confined imaging that is superior to any other super-resolution microscope techniques, including total internal reflection fluorescence (TIRF) microscopy
The LSPR band excited on the sheet exhibits a large red-shift (~100 nm) compared with the band in solution, which is due to the collective excitation of the LSPR in the sheet[26]

Summary

Introduction

Fluorescence microscopy has been a key technology in the field of cell biology for the past several decades. Many developments have been achieved related to fluorescent probe technologies for visualizing detailed structures and functions or their dynamic processes in chemically fixed or living cells[1,2,3] In most cases, these fluorescence images are collected under the diffraction limit of an optical microscope, e.g., 200 nm in the lateral direction and 500 nm in the axial direction, according to the Abbe and Rayleigh criteria. The light confined by LSPR detects fluorescence molecules in a region of only a few tens of nanometers at the interface[19, 20], which creates notably high ‘axially’ confined imaging that is superior to any other super-resolution microscope techniques, including TIRF microscopy. No ideal system is available that combines the highest spatial resolution and temporal resolution for biological systems, but we expect that this simple, non-scanning imaging method meets both requirements

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