Friday, December 26, 2014

lensfree holographic on-chip microscopy

Actually this shouldn't be that hard to do.  It is computational photography at it's finest.

It should be able to completely put to shame normal optical microscopes.
It is volumetric and 3D viewable and could even go multi-spectral. 

There's no information on the specifics of the optics, but the sample must go directly on the imaging chip or very close to it.

So cleaning and reuse are my only questions.

Lens-free microscope can detect cancer at the cellular level

UCLA researchers develop device that can do the work of pathology lab microscopes

 The latest invention is the first lens-free microscope that can be used for high-throughput 3-D tissue imaging — an important need in the study of disease.

“This is a milestone in the work we’ve been doing,” said Ozcan, who also is the associate director of UCLA’s California NanoSystems Institute. “This is the first time tissue samples have been imaged in 3D using a lens-free on-chip microscope.”

The device works by using a laser or light-emitting-diode to illuminate a tissue or blood sample that has been placed on a slide and inserted into the device. A sensor array on a microchip — the same type of chip that is used in digital cameras, including cellphone cameras — captures and records the pattern of shadows created by the sample.

The device processes these patterns as a series of holograms, forming 3-D images of the specimen and giving medical personnel a virtual depth-of-field view. An algorithm color codes the reconstructed images, making the contrasts in the samples more apparent than they would be in the holograms and making any abnormalities easier to detect.

Wide-field computational imaging of pathology slides using lens-free on-chip microscopy

Alon Greenbaum, Yibo Zhang,  Alborz Feizi, Ping-Luen Chung, Wei Luo, Shivani R. Kandukuri and Aydogan Ozcan

Optical examination of microscale features in pathology slides is one of the gold standards to diagnose disease. However, the use of conventional light microscopes is partially limited owing to their relatively high cost, bulkiness of lens-based optics, small field of view (FOV), and requirements for lateral scanning and three-dimensional (3D) focus adjustment. We illustrate the performance of a computational lens-free, holographic on-chip microscope that uses the transport-of-intensity equation, multi-height iterative phase retrieval, and rotational field transformations to perform wide-FOV imaging of pathology samples with comparable image quality to a traditional transmission lens-based microscope. The holographically reconstructed image can be digitally focused at any depth within the object FOV (after image capture) without the need for mechanical focus adjustment and is also digitally corrected for artifacts arising from uncontrolled tilting and height variations between the sample and sensor planes. Using this lens-free on-chip microscope, we successfully imaged invasive carcinoma cells within human breast sections, Papanicolaou smears revealing a high-grade squamous intraepithelial lesion, and sickle cell anemia blood smears over a FOV of 20.5 mm2. The resulting wide-field lens-free images had sufficient image resolution and contrast for clinical evaluation, as demonstrated by a pathologist’s blinded diagnosis of breast cancer tissue samples, achieving an overall accuracy of ~99%. By providing high-resolution images of large-area pathology samples with 3D digital focus adjustment, lens-free on-chip microscopy can be useful in resource-limited and point-of-care settings.

Toward giga-pixel nanoscopy on a chip: a computational wide-field look at the nano-scale without the use of lenses!divAbstract

The development of lensfree on-chip microscopy in the past decade has opened up various new possibilities for biomedical imaging across ultra-large fields of view using compact, portable, and cost-effective devices. However, until recently, its ability to resolve fine features and detect ultra-small particles has not rivalled the capabilities of the more expensive and bulky laboratory-grade optical microscopes. In this Frontier Review, we highlight the developments over the last two years that have enabled computational lensfree holographic on-chip microscopy to compete with and, in some cases, surpass conventional bright-field microscopy in its ability to image nano-scale objects across large fields of view, yielding giga-pixel phase and amplitude images. Lensfree microscopy has now achieved a numerical aperture as high as 0.92, with a spatial resolution as small as 225 nm across a large field of view e.g., >20 mm2. Furthermore, the combination of lensfree microscopy with self-assembled nanolenses, forming nano-catenoid minimal surfaces around individual nanoparticles has boosted the image contrast to levels high enough to permit bright-field imaging of individual particles smaller than 100 nm. These capabilities support a number of new applications, including, for example, the detection and sizing of individual virus particles using field-portable computational on-chip microscopes.

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