Berlin 2015 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 1: Imaging
BP 1.4: Vortrag
Montag, 16. März 2015, 10:30–10:45, H 1028
3D-Refractive Index Measurements of Single Cells by Optical Diffraction Tomography — •Paul Müller1, Mirjam Schürmann1, Christoph Faigle1, Moritz Kreysing2, and Jochen Guck1 — 1Biotechnology Center of the TU Dresden — 2Max Planck Institute of Molecular Cell Biology and Genetics
The refractive index is an inherent property of biological cells. The 3D distribution of the refractive index within a cell determines its light scattering properties. It is possible to reconstruct the refractive index distribution, and thus the internal structure of a cell, from scattering data using optical diffraction tomography (ODT). ODT combines computerized tomography (CT) with the Born approximation to address the wavelike propagation of light through a specimen. In ODT, the phase of the scattered field behind a rotating specimen is measured. From these 2D phase images one can reconstruct the 3D refractive index map of the specimen. Here, we demonstrate quantitative 3D ODT imaging of single biological cells with sub-cellular resolution. The technique does not require a marker and the acquisition of images is contact-free. In this particular study, suspended cells are held in an optical trap and rotated using microfluidic flow or, all-optically, by means of an optical cell rotator (OCR). The phase of the scattered field is measured using digital holographic microscopy (DHM), a quantitative phase microscopy technique. The resulting 3D refractive index map allows us to determine properties such as cell volume, dry mass, or density and refractive index of sub-cellular compartments. Many future applications in biology and medicine are envisioned.