Chapter 2
Interferometric Scattering (iSCAT)
Microscopy and Related Techniques
Richard W. Taylor and Vahid Sandoghdar
Abstract Interferometric scattering (iSCAT) microscopy is a powerful tool for
label-free sensitive detection and imaging of nanoparticles to high spatiotemporal resolution. As it was born out of detection principles central to conventional
microscopy, we begin by surveying the historical development of the microscope to
examine how the exciting possibility for interferometric scattering microscopy with
sensitivities sufficient to observe single molecules has become a reality. We discuss
the theory of interferometric detection and also issues relevant to achieving a high
detection sensitivity and speed. A showcase of numerous applications and avenues
of novel research across various disciplines that iSCAT microscopy has opened up
is also presented.
2.1 Introduction
Super-resolving the position of nanoscopic objects to a precision better than the
wavelength of light is an important and powerful technology in nanoscience and, in
particular, in the rapidly growing field of nanobiology. The forebear to modern superresolution microscopy, where typically one aims to resolve intricate extended cellular
substructures, is fluorescence microscopy. With the advent of single-molecule fluorescent spectroscopy and microscopy in the early 1990s, it became possible to extend
such measurements to fluorescent labels as small as single dye molecules, quantum
dots or single fluorescent proteins [1]. Fluorescence as a contrast mechanism, however, brings about several restrictions. These include (1) the use of the label itself,
which may introduce artifacts to the interpretation, (2) the limited photoemission,
caused by photobleaching and photoblinking as well as (3) saturation which curtails the spatiotemporal resolution and duration of a measurement. Fluorescence-free
alternatives are thus highly desirable to overcome these limitations.
R. W. Taylor · V. Sandoghdar (B)
Max Planck Institute for the Science of Light, 91058 Erlangen, Germany
e-mail: vahid.sandoghdar@mpl.mpg.de
© Springer Nature Switzerland AG 2019
V. Astratov (ed.), Label-Free Super-Resolution Microscopy,
Biological and Medical Physics, Biomedical Engineering,
https://doi.org/10.1007/978-3-030-21722-8_2
25
Interferometric Scattering (iSCAT)
Microscopy and Related Techniques
Richard W. Taylor and Vahid Sandoghdar
Abstract Interferometric scattering (iSCAT) microscopy is a powerful tool for
label-free sensitive detection and imaging of nanoparticles to high spatiotemporal resolution. As it was born out of detection principles central to conventional
microscopy, we begin by surveying the historical development of the microscope to
examine how the exciting possibility for interferometric scattering microscopy with
sensitivities sufficient to observe single molecules has become a reality. We discuss
the theory of interferometric detection and also issues relevant to achieving a high
detection sensitivity and speed. A showcase of numerous applications and avenues
of novel research across various disciplines that iSCAT microscopy has opened up
is also presented.
2.1 Introduction
Super-resolving the position of nanoscopic objects to a precision better than the
wavelength of light is an important and powerful technology in nanoscience and, in
particular, in the rapidly growing field of nanobiology. The forebear to modern superresolution microscopy, where typically one aims to resolve intricate extended cellular
substructures, is fluorescence microscopy. With the advent of single-molecule fluorescent spectroscopy and microscopy in the early 1990s, it became possible to extend
such measurements to fluorescent labels as small as single dye molecules, quantum
dots or single fluorescent proteins [1]. Fluorescence as a contrast mechanism, however, brings about several restrictions. These include (1) the use of the label itself,
which may introduce artifacts to the interpretation, (2) the limited photoemission,
caused by photobleaching and photoblinking as well as (3) saturation which curtails the spatiotemporal resolution and duration of a measurement. Fluorescence-free
alternatives are thus highly desirable to overcome these limitations.
R. W. Taylor · V. Sandoghdar (B)
Max Planck Institute for the Science of Light, 91058 Erlangen, Germany
e-mail: vahid.sandoghdar@mpl.mpg.de
© Springer Nature Switzerland AG 2019
V. Astratov (ed.), Label-Free Super-Resolution Microscopy,
Biological and Medical Physics, Biomedical Engineering,
https://doi.org/10.1007/978-3-030-21722-8_2
25