• Lensless camera captures cellular-level,

    From ScienceDaily@1:317/3 to All on Mon Mar 7 21:30:48 2022
    Lensless camera captures cellular-level, 3D details in living tissue


    Date:
    March 7, 2022
    Source:
    Rice University
    Summary:
    The lensless Bio-FlatScope is a small, inexpensive camera to
    monitor biological activity that can't be captured by conventional
    instruments.

    The device could eventually be used to look for signs of cancer
    or sepsis or become a valuable endoscopy tool.



    FULL STORY ==========================================================================
    Want to monitor the brain of a running tiger?

    ========================================================================== First, catch the tiger.

    Then attach Bio-FlatScope, the latest iteration of lensless microscopy
    being developed at Rice University.

    That particular use is fanciful but not far-fetched, according to Jacob Robinson, an electrical and computer engineer at Rice's George R. Brown
    School of Engineering who led the recent effort to test Bio-FlatScope
    in living creatures.

    The research team's FlatCam, a lensless device that channels light through
    a mask and directly onto a camera sensor, aimed primarily outward at
    the world at large. The raw images looked like static, but a custom
    algorithm used the data they contained to reconstruct what the camera saw.

    The new device looks inward to image micron-scale targets like cells
    and blood vessels inside the body, even through the skin. Bio-FlatScope captures images that no lensed camera can see -- showing, for example,
    dynamic changes in the fluorescent-tagged neurons in running mice.



    ==========================================================================
    One advantage over other microscopes is that light captured by
    Bio-FlatScope can be refocused after the fact to reveal 3D details. And
    without lenses, the scope's field of view is the size of the sensor
    (at close range to the target) or wider, without distortion.

    A small, low-cost Bio-FlatScope could eventually look for signs of
    cancer or sepsis or become a valuable tool for endoscopy, said Robinson,
    who teamed with colleagues at Rice's Neuroengineering Initiative on
    the project.

    The team's proof-of-concept study also imaged plants, hydra and even,
    to a limited degree, a human. Their results appear in Nature Biomedical Engineering.

    The mechanism combines a sophisticated phase mask to generate patterns of
    light that fall directly onto the chip, according to the researchers. The
    mask in the original FlatCam looks something like a bar code and limits
    the amount of light that passes through to the camera sensor. But it
    doesn't work well for biological samples.

    The Bio-FlatScope phase mask looks more like the random map of a natural landscape, with no straight lines. "We had to start from scratch and
    think about how to make it function in a realistic biological setting," Robinson said.



    ========================================================================== "Being random allows the mask to be pretty diverse in gathering light
    from all directions," said postdoctoral researcher Vivek Boominathan,
    one of four lead authors on the study. "And then we take the random
    input, which is called Perlin noise, and do some processing to get these high-contrast contours." At the sensor, light that comes through the
    mask appears as a point spread function, a pair of blurry blobs that
    seems useless but is actually key to acquiring details about objects
    below the diffraction limit that are too small for many microscopes to
    see. The blobs' size, shape and distance from each other indicate how
    far the subject is from the focal plane. Software reinterprets the data
    into an image that can be refocused at will.

    A tiger was a little beyond their budget, so the researchers started
    small, first capturing cellular structures in a lily of the valley,
    then calcium activity in tiny, jellyfishlike hydra. They moved on to
    monitoring a running rodent, attaching the Bio-FlatScope to a rodent's
    skull and setting it down on a wheel. The data showed fluorescent-tagged neurons in a region of the animal's brain, connecting activity in the
    motor cortex with motion and resolving blood vessels as small as 10
    microns in diameter.

    In collaboration with Rebecca Richards-Kortum and research scientist
    Jennifer Carns from Rice Bioengineering, the team identified vascular
    imaging as a potential clinical application of the Bio-FlatScope. Graduate student and co- lead author Jimin Wu offered her lower lip to see if
    light passing through to the camera could deliver structural details of
    the blood vessels within.

    "It was kind of an engineering challenge because it's difficult to
    position the Bio-FlatScope at the correct position and keep it there,"
    Wu said. "But it showed us it could be a good tool for seeing signs of
    sepsis, because pre- sepsis changes the density of the vasculature. Cancer
    also alters the morphology of the microvasculature." "We can imagine
    it would be hard to stick a microscope in that position, but maybe a
    little clip you put on your lip would be able to look for things like
    sepsis or tumors in the oral mucosa," Robinson said.

    Long term, the team sees potential for a camera that could curve around
    its subject, like brain tissue, "so it could match the morphology of
    what you're looking at," Robinson said. "Or maybe you could fold it up,
    stick it in place and have it unfold and deploy.

    "You could also do really interesting things by bending it for a fisheye effect, or you could curve it inward and have very high light-collection efficiency," he said.

    Co-lead authors of the study include Rice alumnus Jesse Adams and Applied Physics graduate student Dong Yan. Co-authors are Rice graduate students
    Sibo Gao and Soonyoung Kim; postdoctoral alumnus Alex Rodriguez; Caleb
    Kemere, an associate professor of electrical and computer engineering
    and of bioengineering; and Ashok Veeraraghavan, a professor of electrical
    and computer engineering.

    Richards-Kortum is the Malcolm Gillis University Professor, a professor
    of bioengineering and electrical and computer engineering and director
    of the Rice360 Institute for Global Health Technology. Robinson is
    an associate professor of electrical and computer engineering and of bioengineering, and he, Kemere and Veeraraghavan are core members of
    the Rice Neuroengineering Initiative.

    The Defense Advanced Research Projects Agency (N66001-17-C-4012), the
    National Institutes of Health (RF1NS110501) and the National Science
    Foundation (1730574) supported the research.

    ========================================================================== Story Source: Materials provided by Rice_University. Original written
    by Mike Williams. Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Adams, J.K., Yan, D., Wu, J. et al. In vivo lensless microscopy
    via a
    phase mask generating diffraction patterns with high-contrast
    contours.

    Nat Biomed Eng, 2022 DOI: 10.1038/s41551-022-00851-z ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220307112957.htm

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