Tracking of fluorescence nanoparticles with nanometre resolution in a biological system

Assessing local viscosity and microrheology

Alex Marki, Eugeny Ermilov, Andreas Zakrzewicz, Akos Koller, Timothy W Secomb, Axel R. Pries

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The aim of the study was to establish a user-friendly approach for single fluorescence particle 3D localization and tracking with nanometre precision in a standard fluorescence microscope using a point spread function (PSF) approach, and to evaluate validity and precision for different analysis methods and optical conditions with particular application to microcirculatory flow dynamics and cell biology. Images of fluorescent particles were obtained with a standard fluorescence microscope equipped with a piezo positioner for the objective. Whole pattern (WP) comparison with a PSF recorded for the specific set-up and measurement of the outermost ring radius (ORR) were used for analysis. Images of fluorescent particles were recorded over a large range (about 7 μ m) of vertical positions, with and without distortion by overlapping particles as well as in the presence of cultured endothelial cells. For a vertical range of 6.5 μ m, the standard deviation (SD) from the predicted value, indicating validity, was 9.3/8.7 nm (WP/ORR) in the vertical and 8.2/11.7 nm in the horizontal direction. The precision, determined by repeated measurements, was 5.1/3.8 nm in the vertical and 2.9/3.7 nm in the horizontal direction. WP was more robust with respect to underexposure or overlapping images. On the surface of cultured endothelial cells, a layer with 2.5 times increased viscosity and a thickness of about 0.8 μ m was detected. With a validity in the range of 10 nm and a precision down to about 3-5 nm obtained by standard fluorescent microscopy, the PSF approach offers a valuable tool for a variety of experimental investigations of particle localizations, including the assessment of endothelial cell microenvironment.

Original languageEnglish (US)
Pages (from-to)275-288
Number of pages14
JournalBiomechanics and Modeling in Mechanobiology
Volume13
Issue number2
DOIs
StatePublished - 2014

Fingerprint

Endothelial cells
Optical transfer function
Biological systems
Biological Systems
Viscosity
Nanoparticles
Fluorescence
Endothelial Cells
Vertical
Cultured Cells
Microscopes
Cytology
Cellular Microenvironment
Microscope
Overlapping
Horizontal
Radius
Cell Biology
Microscopy
Range of data

Keywords

  • Defocus imaging
  • Particle tracking
  • Resolution enhancement

ASJC Scopus subject areas

  • Biotechnology
  • Mechanical Engineering
  • Modeling and Simulation
  • Medicine(all)

Cite this

Tracking of fluorescence nanoparticles with nanometre resolution in a biological system : Assessing local viscosity and microrheology. / Marki, Alex; Ermilov, Eugeny; Zakrzewicz, Andreas; Koller, Akos; Secomb, Timothy W; Pries, Axel R.

In: Biomechanics and Modeling in Mechanobiology, Vol. 13, No. 2, 2014, p. 275-288.

Research output: Contribution to journalArticle

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