Medical Design Briefs - June 2021 - 28

a
Connected to micromanipulator
488 nm
laser beam
Scanning system
Obj.
MEMS mirror
f = 35 mm
f = 150 mm
Fiber bundle facet (core addressing)
Fiber
bundle
Probe chip
Mouse brain
Optical addressing method and proposal for deep-brain photonic-probe-enabled light-sheet fluorescence microscopy (LSFM). Schematic of the optical
addressing method (not to scale) (a). The scanning system addresses on-chip edge couplers via spatial addressing of the cores of an image fiber bundle.
Bottom inset: micrographs of the distal facet of a fiber bundle connected to the scanning system with different cores addressed. Top inset: annotated
photograph of a packaged light-sheet neural probe inserted into an agarose block. Illustration of the proposed use of the light-sheet neural probe with
a GRIN lens endoscope for deep brain LSFM (not to scale) (b). (Credit: Sacher et al., doi 10.1117/1.NPh.8.2.025003)
a new study reported in Neurophotonics, an
international team of researchers from the
California Institute of Technology (USA),
University of Toronto (Canada), Uni -
versity Health Network (Canada), the Max
Planck Institute of Microstructure Physics
(Germany), and Advanced Micro Foundry
(Singapore) developed a miniature lightsheet
generator, or a photonic neural
probe, that can be implanted into a living
animal's brain.
The researchers used nanophotonic
technology to create ultrathin siliconbased
photonic neural probes that emit
multiple addressable thin sheets of light
with thicknesses <16 micrometers over
propagation distances of 300 micrometers
in free space. When tested in brain tissues
from mice that were genetically engineered
to express fluorescent proteins in
their brains, the probes permitted the
researchers to image areas as large as 240
× 490 μm. Moreover, the level of image
contrast was superior to that with an alternative
imaging method called epifluorescence
microscopy.
Describing the significance of his team's
work, the study's lead author, Wesley
Sacher, says, " This new implantable photonic
neural probe technology for generating
light sheets within the brain circumvents
many of the constraints that have
limited the use of light-sheet fluorescence
imaging in experimental neuroscience.
We predict that this technology will lead to
new variants of light-sheet microscopy for
deep brain imaging and behavior experiments
with freely moving animals. "
Such variants would be a boon to neuroscientists
seeking to understand the workings
of the brain.
The open access research article, W.D.
Sacher et al., " Implantable photonic
neural probes for light-sheet fluorescence
brain imaging, " was published in
Neurophotonics 8(2), 025003, doi 10.
1117/1.NPh.8.2.025003.
For more information, visit https://spie.org.
E-health Patches Monitor Pulse and Blood Pressure
The wireless patches
power themselves with
harvested energy.
Osaka University
Osaka, Japan
Scientists at Osaka University, in cooperation
with Joanneum Research (Weiz,
Austria), have introduced wireless health
monitoring patches that use embedded
piezoelectric nanogenerators to power
themselves with harvested biomechanical
energy. This work may lead to new
autonomous health sensors as well as battery-less
wearable electronic devices.
28
Cov
Power generation
device using
ferroelectric polymer
Organic
Rectifier
Circuit
Energy
Strorage
Capacitor
Organic
Piezoelectric
Sensors
Fiber bundle
Probe
Chip
Carrier
Chip
b
Image
sensor
Tube lens
Bandpass filter
Electrically
tunable lens
Objective
Fluorescence
GRIN lens
Substrate thickness : 1μm
Total thickess
< 2.5 μm
Fig. 1 - Sheet-type piezoelectric system with self-generation and storage functions.
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ToC
Medical Design Briefs, June 2021
Imaging system
Fiber
bundle
Agarose

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Medical Design Briefs - June 2021

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