New paper in Biomedical Optics Express

Generalized cell morphological parameters based on interferometric phase microscopy and their application to cell life cycle characterization

Pinhas Girshovitz and Natan T. Shaked

Abstract: We present analysis tools which are formulated using wide-field interferometric phase microscopy measurements, and show their ability to uniquely quantify the life cycle of live cancer cells. These parameters are based directly on the optical path delay profile of the sample and do not necessitate decoupling the refractive index and thickness in the cell interferometric phase profile, and thus can be calculated using a singleframe acquisition. To demonstrate the use of these parameters, we have constructed a wide-field interferometric phase microscopy setup and closely traced the full lifecycle of HeLa cancer cells. These initial results show the potential of the parameters to distinguish between the different phases of the cell lifecycle, as well others biological phenomena.

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New book: Biomedical Optical Phase Microscopy and Nanoscopy (Elsevier)

By: N. T. Shaked, Z. Zalevsky and L. L. Satterwhite (Eds.)

Ready for early purchases on Amazon [Link].
Official publication date is September 2012.
Book details are [Here].

New paper in Journal of Biomedical Optics

Optical phase nanoscopy in red blood cells using low-coherence spectroscopy

Itay Shock, Alexander Barbul, Pinhas Girshovitz, Uri Nevo, Rafi Korenstein, and Natan T. Shaked

Abstract: We propose a low-coherence spectral-domain phase microscopy (SDPM) system for accurate quantitative phase measurements in red blood cells (RBCs) for the prognosis and monitoring of disease conditions that affect the visco-elastic properties of RBCs. Using the system, we performed time-recordings of cell membrane fluctuations, and compared the nano-scale fluctuation dynamics of healthy and glutaraldehyde-treated RBCs. Glutaraldehyde-treated RBCs possess a lower amplitude of fluctuations reflecting an increased membrane stiffness. To demonstrate the ability of our system to measure fluctuations of lower amplitudes than those measured by the commonly used holographic phase microscopy techniques, we also constructed a wide-field digital interferometric microscope and compared the performances of the two systems. Due to its common-path geometry, the optical-path-delay stability of SDPM was found to be less than 0.3nm in liquid environment, at least three times better than in holographic phase microscopy under the same conditions. In addition, due to the compactness of SDPM and its inexpensive and robust design, the system possesses a high potential for clinical applications.

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New paper in Optics Letters

Quantitative phase microscopy of biological samples using a portable interferometer

Natan T. Shaked

Optics Letters Vol. 37, No. 11, 2016-2019, 2012

Abstract: The Letter presents the τ interferometer, a portable and inexpensive device for obtaining spatial interferograms of microscopic biological samples, without the strict stability and the highly-coherent illumination that are usually required for interferometric microscopy setups. The device is built using off-the-shelf optical elements and can easily operate with low-coherence illumination, whil being positioned in the output of a conventional inverted microscope. The interferograms are processed into the quantitative amplitude and phase profiles of the sample. Based on the phase profile, the optical path delay profile is obtained with temporal stability of 0.18 nm and spatial stability of 0.42 nm. Further experimental demonstration of using the τ interferometer for imaging the quantitative thickness profile of live red blood cell is provided.

[Download PDF] [Link]

New conference paper

New paper that will be presented orally in SPIE Photonics West
(Biomedical Spectroscopy, Microscopy, and Imaging: Biomedical Applications of Light Scattering VI)
Optical phase measurements in red blood cells using low-coherence spectroscopy

By: Itay Shock, Uri Nevo, Natan T. Shaked

Where: Moscone Center, San Francisco, California, USA
When: 1:40PM, Saturday, 21 January 2012


New paper accepted to Optics Express

Compact and portable low-coherence interferometer with off-axis geometry for quantitative phase microscopy and nanoscopy
Pinhas Girshovitz and Natan T. Shaked
We present a new simple-to-align, highly-portable interferometer, which is able to capture wide-field, off-axis interference patterns from transparent samples under low-coherence illumination. This small-dimensions and low-cost device can be connected to the output of an inverted microscope illuminated by a low-coherence source and measure sub-nanometric optical thickness changes in a label-free manner. In contrast to our previously published design, the interferometer, the new design is able to fully operate in an off-axis holographic geometry, where the interference fringes have high spatial frequency, and the interference area is limited only by the coherence length of the source, and thus it enables to easily obtain high-quality quantitative images of static and dynamic samples. We present several applications for the new design including nondestructive optical testing of transparent microscopic elements with nanometric thickness and live-cell imaging.