Interferometric scattering microscopy

Last updated
Typical iSCAT configurations where either the reflected light from the cover-slip (a, c) or the transmitted light through the sample (b, d) is used as a reference field. The signal can be acquired with a camera in wide-field operation (a, b) or by point detection in confocal arrangement (c, d). ISCAT setup configurations.svg
Typical iSCAT configurations where either the reflected light from the cover-slip (a, c) or the transmitted light through the sample (b, d) is used as a reference field. The signal can be acquired with a camera in wide-field operation (a, b) or by point detection in confocal arrangement (c, d).

Interferometric scattering microscopy (iSCAT) refers to a class of methods that detect and image a subwavelength object by interfering the light scattered by it with a reference light field. The underlying physics is shared by other conventional interferometric methods such as phase contrast or differential interference contrast, or reflection interference microscopy. The key feature of iSCAT is the detection of elastic scattering from subwavelength particles, also known as Rayleigh scattering, in addition to reflected or transmission signals from supra-wavelength objects. Typically, the challenge is the detection of tiny signals on top of large and complex, speckle-like backgrounds. iSCAT has been used to investigate nanoparticles such as viruses, proteins, lipid vesicles, DNA, exosomes, metal nanoparticles, semiconductor quantum dots, charge carriers and single organic molecules without the need for a fluorescent label.

Contents

Historical background

The principle of interference plays a central role in many imaging methods, including bright-field imaging because it can be described as the interference between the illumination field and the one that has interacted with the object, i.e. through extinction. In fact, even microscopy based on the interference with an external light field is more than one hundred years old.

The first iSCAT-type of measurements were performed in the biophysics community in the 1990s. [1] A systematic development of the method for the detection of nano-objects started in the early 2000s as a general effort to explore fluorescence-free options for studying single molecules and nano-objects. [2] In particular, gold nanoparticles down to a size of 5 nm were imaged via the interference of their scattered light with a reflected beam from the cover-slip supporting them. Using a supercontinuum laser additionally allowed for recording the particles' plasmon spectra. [2] The early measurements were limited by residual speckle-like background. A new approach to background subtraction and the acronym iSCAT were introduced in 2009. [3] Since then, a series of important works has been reported by various groups. [4] [5] [6] [7] Notably, further innovations in background and noise suppression have led to the development of new quantification methods such as mass photometry (originally introduced as iSCAMS), in which ultrasensitive and accurate interferometric detection is converted into a quantitative means for measuring the molecular mass of single biomolecules. [8]

Theoretical background

When a reference light is superposed with an object's scattered light, the intensity at the detector can be described by, [2] [7]

where and  are the complex electric fields of the reference and scattered light. The resulting terms are the intensity of the reference beam , the pure scattered light from the object , and the cross-term which contains a phase . This phase comprises a Gouy phase component from the variations of the wave vectors, a scattering phase component from the material properties of the object, and a sinusoidally modulating phase component which depends on the position of the particle.

In general, the reference beam can take a different path than the scattered light within the optical setup, as long as they are coherent and interfere on the detector. However, the technique becomes simpler and more stable if both beams share the same optical path. Therefore, the reflected light off the cover-slip or the transmitted beam through the sample is typically used as the reference. For the interference to occur, it is necessary that both light waves (scattered light and reference light) are coherent. Interestingly, a light source with a large coherence length on the order of meters or more (like in modern narrow-band laser systems) is typically not needed. In the most common iSCAT realization schemes where the reflected light of a cover-slip is used as a reference and the scattering particle is not more than a few hundreds of nanometers above the glass, even "incoherent" light, e.g. from LEDs, can be used. [9]

Applications

iSCAT has been used in multiple applications. These can be grouped roughly as:

Label-free imaging

Single particle tracking

Label-free single molecule detection, imaging, tracking and quantification

Ion tracking

Related Research Articles

<span class="mw-page-title-main">Raman spectroscopy</span> Spectroscopic technique

Raman spectroscopy is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which molecules can be identified.

<span class="mw-page-title-main">Colloidal gold</span> Suspension of gold nanoparticles in a liquid

Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid, usually water. The colloid is coloured usually either wine red or blue-purple . Due to their optical, electronic, and molecular-recognition properties, gold nanoparticles are the subject of substantial research, with many potential or promised applications in a wide variety of areas, including electron microscopy, electronics, nanotechnology, materials science, and biomedicine.

<span class="mw-page-title-main">Nanoparticle</span> Particle with size less than 100 nm

A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At the lowest range, metal particles smaller than 1 nm are usually called atom clusters instead.

In physics, the Hanbury Brown and Twiss (HBT) effect is any of a variety of correlation and anti-correlation effects in the intensities received by two detectors from a beam of particles. HBT effects can generally be attributed to the wave–particle duality of the beam, and the results of a given experiment depend on whether the beam is composed of fermions or bosons. Devices which use the effect are commonly called intensity interferometers and were originally used in astronomy, although they are also heavily used in the field of quantum optics.

<span class="mw-page-title-main">Surface-enhanced Raman spectroscopy</span> Spectroscopic technique

Surface-enhanced Raman spectroscopy or surface-enhanced Raman scattering (SERS) is a surface-sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces or by nanostructures such as plasmonic-magnetic silica nanotubes. The enhancement factor can be as much as 1010 to 1011, which means the technique may detect single molecules.

<span class="mw-page-title-main">Spectral phase interferometry for direct electric-field reconstruction</span>

In ultrafast optics, spectral phase interferometry for direct electric-field reconstruction (SPIDER) is an ultrashort pulse measurement technique originally developed by Chris Iaconis and Ian Walmsley.

<span class="mw-page-title-main">Near-field scanning optical microscope</span>

Near-field scanning optical microscopy (NSOM) or scanning near-field optical microscopy (SNOM) is a microscopy technique for nanostructure investigation that breaks the far field resolution limit by exploiting the properties of evanescent waves. In SNOM, the excitation laser light is focused through an aperture with a diameter smaller than the excitation wavelength, resulting in an evanescent field on the far side of the aperture. When the sample is scanned at a small distance below the aperture, the optical resolution of transmitted or reflected light is limited only by the diameter of the aperture. In particular, lateral resolution of 6 nm and vertical resolution of 2–5 nm have been demonstrated.

Nanoparticle tracking analysis (NTA) is a method for visualizing and analyzing particles in liquids that relates the rate of Brownian motion to particle size. The rate of movement is related only to the viscosity and temperature of the liquid; it is not influenced by particle density or refractive index. NTA allows the determination of a size distribution profile of small particles with a diameter of approximately 10–1000 nanometers (nm) in liquid suspension.

Fluorescence interference contrast (FLIC) microscopy is a microscopic technique developed to achieve z-resolution on the nanometer scale.

Particle size analysis, particle size measurement, or simply particle sizing, is the collective name of the technical procedures, or laboratory techniques which determines the size range, and/or the average, or mean size of the particles in a powder or liquid sample.

A model lipid bilayer is any bilayer assembled in vitro, as opposed to the bilayer of natural cell membranes or covering various sub-cellular structures like the nucleus. They are used to study the fundamental properties of biological membranes in a simplified and well-controlled environment, and increasingly in bottom-up synthetic biology for the construction of artificial cells. A model bilayer can be made with either synthetic or natural lipids. The simplest model systems contain only a single pure synthetic lipid. More physiologically relevant model bilayers can be made with mixtures of several synthetic or natural lipids.

Photothermal optical microscopy / "photothermal single particle microscopy" is a technique that is based on detection of non-fluorescent labels. It relies on absorption properties of labels, and can be realized on a conventional microscope using a resonant modulated heating beam, non-resonant probe beam and lock-in detection of photothermal signals from a single nanoparticle. It is the extension of the macroscopic photothermal spectroscopy to the nanoscopic domain. The high sensitivity and selectivity of photothermal microscopy allows even the detection of single molecules by their absorption. Similar to Fluorescence Correlation Spectroscopy (FCS), the photothermal signal may be recorded with respect to time to study the diffusion and advection characteristics of absorbing nanoparticles in a solution. This technique is called photothermal correlation spectroscopy (PhoCS).

The N-slit interferometer is an extension of the double-slit interferometer also known as Young's double-slit interferometer. One of the first known uses of N-slit arrays in optics was illustrated by Newton. In the first part of the twentieth century, Michelson described various cases of N-slit diffraction.

<span class="mw-page-title-main">Plasmonic nanoparticles</span>

Plasmonic nanoparticles are particles whose electron density can couple with electromagnetic radiation of wavelengths that are far larger than the particle due to the nature of the dielectric-metal interface between the medium and the particles: unlike in a pure metal where there is a maximum limit on what size wavelength can be effectively coupled based on the material size.

Photo-activated localization microscopy and stochastic optical reconstruction microscopy (STORM) are widefield fluorescence microscopy imaging methods that allow obtaining images with a resolution beyond the diffraction limit. The methods were proposed in 2006 in the wake of a general emergence of optical super-resolution microscopy methods, and were featured as Methods of the Year for 2008 by the Nature Methods journal. The development of PALM as a targeted biophysical imaging method was largely prompted by the discovery of new species and the engineering of mutants of fluorescent proteins displaying a controllable photochromism, such as photo-activatible GFP. However, the concomitant development of STORM, sharing the same fundamental principle, originally made use of paired cyanine dyes. One molecule of the pair, when excited near its absorption maximum, serves to reactivate the other molecule to the fluorescent state.

<span class="mw-page-title-main">Fluctuation X-ray scattering</span>

Fluctuation X-ray scattering (FXS) is an X-ray scattering technique similar to small-angle X-ray scattering (SAXS), but is performed using X-ray exposures below sample rotational diffusion times. This technique, ideally performed with an ultra-bright X-ray light source, such as a free electron laser, results in data containing significantly more information as compared to traditional scattering methods.

<span class="mw-page-title-main">Nano-FTIR</span> Infrared microscopy technique

Nano-FTIR is a scanning probe technique that utilizes as a combination of two techniques: Fourier transform infrared spectroscopy (FTIR) and scattering-type scanning near-field optical microscopy (s-SNOM). As s-SNOM, nano-FTIR is based on atomic-force microscopy (AFM), where a sharp tip is illuminated by an external light source and the tip-scattered light is detected as a function of tip position. A typical nano-FTIR setup thus consists of an atomic force microscope, a broadband infrared light source used for tip illumination, and a Michelson interferometer acting as Fourier-transform spectrometer. In nano-FTIR, the sample stage is placed in one of the interferometer arms, which allows for recording both amplitude and phase of the detected light. Scanning the tip allows for performing hyperspectral imaging with nanoscale spatial resolution determined by the tip apex size. The use of broadband infrared sources enables the acquisition of continuous spectra, which is a distinctive feature of nano-FTIR compared to s-SNOM. Nano-FTIR is capable of performing infrared (IR) spectroscopy of materials in ultrasmall quantities and with nanoscale spatial resolution. The detection of a single molecular complex and the sensitivity to a single monolayer has been shown. Recording infrared spectra as a function of position can be used for nanoscale mapping of the sample chemical composition, performing a local ultrafast IR spectroscopy and analyzing the nanoscale intermolecular coupling, among others. A spatial resolution of 10 nm to 20 nm is routinely achieved.

Scanning quantum dot microscopy (SQDM) is a scanning probe microscopy (SPM) that is used to image nanoscale electric potential distributions on surfaces. The method quantifies surface potential variations via their influence on the potential of a quantum dot (QD) attached to the apex of the scanned probe. SQDM allows, for example, the quantification of surface dipoles originating from individual adatoms, molecules, or nanostructures. This gives insights into surface and interface mechanisms such as reconstruction or relaxation, mechanical distortion, charge transfer and chemical interaction. Measuring electric potential distributions is also relevant for characterizing organic and inorganic semiconductor devices which feature electric dipole layers at the relevant interfaces. The probe to surface distance in SQDM ranges from 2 nm to 10 nm and therefore allows imaging on non-planar surfaces or, e.g., of biomolecules with a distinct 3D structure. Related imaging techniques are Kelvin Probe Force Microscopy (KPFM) and Electrostatic Force Microscopy (EFM).

Philipp Kukura FRSC is Professor of Chemistry at the University of Oxford, and a Fellow of Exeter College, Oxford. He is best known for pioneering contributions to femtosecond stimulated Raman spectroscopy (FSRS), interferometric scattering microscopy (iSCAT) and the development of mass photometry.

Bimodal Atomic Force Microscopy is an advanced atomic force microscopy technique characterized by generating high-spatial resolution maps of material properties. Topography, deformation, elastic modulus, viscosity coefficient or magnetic field maps might be generated. Bimodal AFM is based on the simultaneous excitation and detection of two eigenmodes (resonances) of a force microscope microcantilever.

References

  1. 1 2 AMOS, L. A.; AMOS, W. B. (1991-01-01). "The bending of sliding microtubules imaged by confocal light microscopy and negative stain electron microscopy". Journal of Cell Science. 1991 (Supplement 14): 95–101. doi: 10.1242/jcs.1991.supplement_14.20 . ISSN   0021-9533. PMC   2561856 . PMID   1715872.
  2. 1 2 3 Lindfors, K.; Kalkbrenner, T.; Stoller, P.; Sandoghdar, V. (July 2004). "Detection and Spectroscopy of Gold Nanoparticles Using Supercontinuum White Light Confocal Microscopy". Physical Review Letters. 93 (3): 037401. Bibcode:2004PhRvL..93c7401L. doi:10.1103/physrevlett.93.037401. ISSN   0031-9007. PMID   15323866.
  3. 1 2 Kukura, Philipp; Ewers, Helge; Müller, Christian; Renn, Alois; Helenius, Ari; Sandoghdar, Vahid (2009-11-01). "High-speed nanoscopic tracking of the position and orientation of a single virus". Nature Methods. 6 (12): 923–927. doi:10.1038/nmeth.1395. ISSN   1548-7091. PMID   19881510. S2CID   10615639.
  4. ↑ Hsieh, Chia-Lung (September 2018). "Label-free, ultrasensitive, ultrahigh-speed scattering-based interferometric imaging". Optics Communications. 422: 69–74. Bibcode:2018OptCo.422...69H. doi:10.1016/j.optcom.2018.02.058. ISSN   0030-4018. S2CID   125505926.
  5. ↑ Label-free super-resolution microscopy. Astratov, Vasily. Cham. 31 August 2019. ISBN   978-3-030-21722-8. OCLC   1119720519.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  6. ↑ Young, Gavin; Kukura, Philipp (2019-06-14). "Interferometric Scattering Microscopy". Annual Review of Physical Chemistry. 70 (1): 301–322. Bibcode:2019ARPC...70..301Y. doi:10.1146/annurev-physchem-050317-021247. ISSN   0066-426X. PMID   30978297. S2CID   195661687.
  7. 1 2 Taylor, Richard W.; Sandoghdar, Vahid (2019-07-17). "Interferometric Scattering Microscopy: Seeing Single Nanoparticles and Molecules via Rayleigh Scattering". Nano Letters. 19 (8): 4827–4835. Bibcode:2019NanoL..19.4827T. doi: 10.1021/acs.nanolett.9b01822 . ISSN   1530-6984. PMC   6750867 . PMID   31314539.
  8. 1 2 Young, Gavin; Hundt, Nikolas; Cole, Daniel; Fineberg, Adam; Andrecka, Joanna; Tyler, Andrew; Olerinyova, Anna; Ansari, Ayla; Marklund, Erik G.; Collier, Miranda P.; Chandler, Shane A. (2018-04-27). "Quantitative mass imaging of single biological macromolecules". Science. 360 (6387): 423–427. Bibcode:2018Sci...360..423Y. doi:10.1126/science.aar5839. ISSN   0036-8075. PMC   6103225 . PMID   29700264.
  9. ↑ Daaboul, G.G.; Vedula, R.S.; Ahn, S.; Lopez, C.A.; Reddington, A.; Ozkumur, E.; Ünlü, M.S. (January 2011). "LED-based Interferometric Reflectance Imaging Sensor for quantitative dynamic monitoring of biomolecular interactions". Biosensors and Bioelectronics. 26 (5): 2221–2227. doi:10.1016/j.bios.2010.09.038. ISSN   0956-5663. PMID   20980139.
  10. ↑ Vala, Milan; Bujak, Łukasz; García Marín, Antonio; Holanová, Kristýna; Henrichs, Verena; Braun, Marcus; Lánský, Zdeněk; Piliarik, Marek (2021-01-25). "Nanoscopic Structural Fluctuations of Disassembling Microtubules Revealed by Label-Free Super-Resolution Microscopy". Small Methods. 5 (4): 2000985. doi: 10.1002/smtd.202000985 . ISSN   2366-9608. PMID   34927839. S2CID   234070923.
  11. ↑ Küppers, Michelle; Albrecht, David; Kashkanova, Anna D.; Lühr, Jennifer; Sandoghdar, Vahid (7 April 2023). "Confocal interferometric scattering microscopy reveals 3D nanoscopic structure and dynamics in live cells". Nature Communications. 14 (1): 1962. Bibcode:2023NatCo..14.1962K. doi:10.1038/s41467-023-37497-7. ISSN   2041-1723. PMC   10081331 . PMID   37029107.
  12. ↑ de Wit, Gabrielle; Danial, John S. H.; Kukura, Philipp; Wallace, Mark I. (2015-09-23). "Dynamic label-free imaging of lipid nanodomains". Proceedings of the National Academy of Sciences. 112 (40): 12299–12303. Bibcode:2015PNAS..11212299D. doi: 10.1073/pnas.1508483112 . ISSN   0027-8424. PMC   4603517 . PMID   26401022.
  13. ↑ Garmann, Rees F.; Goldfain, Aaron M.; Manoharan, Vinothan N. (2018). "Measurements of the self-assembly kinetics of individual viral capsids around their RNA genome". Proceedings of the National Academy of Sciences. 116 (45): 22485–22490. arXiv: 1802.05211 . doi: 10.1073/pnas.1909223116 . PMC   6842639 . PMID   31570619.
  14. ↑ Penwell, Samuel B.; Ginsberg, Lucas D. S.; Noriega, Rodrigo; Ginsberg, Naomi S. (2017-09-18). "Resolving ultrafast exciton migration in organic solids at the nanoscale". Nature Materials. 16 (11): 1136–1141. arXiv: 1706.08460 . Bibcode:2017NatMa..16.1136P. doi:10.1038/nmat4975. ISSN   1476-1122. PMID   28920937. S2CID   205416059.
  15. ↑ Huang, Yi-Fan; Zhuo, Guan-Yu; Chou, Chun-Yu; Lin, Cheng-Hao; Chang, Wen; Hsieh, Chia-Lung (2017-01-13). "Coherent Brightfield Microscopy Provides the Spatiotemporal Resolution To Study Early Stage Viral Infection in Live Cells". ACS Nano. 11 (3): 2575–2585. doi:10.1021/acsnano.6b05601. ISSN   1936-0851. PMID   28067508.
  16. ↑ Taylor, Richard W.; Mahmoodabadi, Reza Gholami; Rauschenberger, Verena; Giessl, Andreas; Schambony, Alexandra; Sandoghdar, Vahid (July 2019). "Interferometric scattering microscopy reveals microsecond nanoscopic protein motion on a live cell membrane". Nature Photonics. 13 (7): 480–487. Bibcode:2019NaPho..13..480T. doi:10.1038/s41566-019-0414-6. ISSN   1749-4893. S2CID   195094855.
  17. ↑ Andrecka, J.; Takagi, Y.; Mickolajczyk, K.J.; Lippert, L.G.; Sellers, J.R.; Hancock, W.O.; Goldman, Y.E.; Kukura, P. (2016), "Interferometric Scattering Microscopy for the Study of Molecular Motors", Single-Molecule Enzymology: Fluorescence-Based and High-Throughput Methods, vol. 581, Elsevier, pp. 517–539, doi:10.1016/bs.mie.2016.08.016, ISBN   978-0-12-809267-5, PMC   5098560 , PMID   27793291
  18. ↑ Bujak, Łukasz; Holanová, Kristýna; García Marín, Antonio; Henrichs, Verena; Barvík, Ivan; Braun, Marcus; Lánský, Zdeněk; Piliarik, Marek (2021-08-16). "Fast Leaps between Millisecond Confinements Govern Ase1 Diffusion along Microtubules". Small Methods. 5 (10): 2100370. doi:10.1002/smtd.202100370. ISSN   2366-9608. PMID   34927934. S2CID   238695264.
  19. ↑ Kukura, Philipp; Celebrano, Michele; Renn, Alois; Sandoghdar, Vahid (2010-11-11). "Single-Molecule Sensitivity in Optical Absorption at Room Temperature". The Journal of Physical Chemistry Letters. 1 (23): 3323–3327. doi:10.1021/jz101426x. ISSN   1948-7185.
  20. ↑ Piliarik, Marek; Sandoghdar, Vahid (2014-07-29). "Direct optical sensing of single unlabelled proteins and super-resolution imaging of their binding sites". Nature Communications. 5 (1): 4495. arXiv: 1310.7460 . Bibcode:2014NatCo...5.4495P. doi: 10.1038/ncomms5495 . ISSN   2041-1723. PMID   25072241.
  21. ↑ Dahmardeh, Mahyar; Mirzaalian Dastjerdi, Houman; Mazal, Hisham; Köstler, Harald; Sandoghdar, Vahid (2023-02-27). "Self-supervised machine learning pushes the sensitivity limit in label-free detection of single proteins below 10 kDa". Nature Methods. 20 (3): 442–447. doi: 10.1038/s41592-023-01778-2 . ISSN   1548-7105. PMC   9998267 . PMID   36849549.
  22. ↑ Spillane, Katelyn M.; Ortega-Arroyo, Jaime; de Wit, Gabrielle; Eggeling, Christian; Ewers, Helge; Wallace, Mark I.; Kukura, Philipp (2014-08-27). "High-Speed Single-Particle Tracking of GM1 in Model Membranes Reveals Anomalous Diffusion due to Interleaflet Coupling and Molecular Pinning". Nano Letters. 14 (9): 5390–5397. Bibcode:2014NanoL..14.5390S. doi: 10.1021/nl502536u . ISSN   1530-6984. PMC   4160260 . PMID   25133992.
  23. ↑ Lavars, Nick (June 24, 2021). "Real-time view of lithium ions in motion opens door to next-gen batteries". New Atlas. Retrieved 2021-06-24.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.