Low-cost, 3D printed device may broaden focused ultrasound use

Date:
February 22, 2022
Source:
Washington University in St. Louis
Summary:
Medical researchers have developed a method for producing a
low-cost, easy-to-use focused ultrasound device that can help
open up the blood- brain barrier for non-invasive procedures
and diagnostics.



FULL STORY ========================================================================== Researchers and clinicians have been working to use focused ultrasound
combined with microbubbles to open the blood-brain barrier (BBB) for
both noninvasive diagnostic use as well as to deliver treatments to
the brain for tumors and neurodegenerative diseases. However, the few
existing devices for preclinical research are expensive, bulky and lack
the precision needed for small animal research.


==========================================================================
Hong Chen, associate professor of biomedical engineering at the McKelvey
School of Engineering and of radiation oncology at the School of Medicine
at Washington University in St. Louis, and her team have developed
a low-cost, easy-to-use and highly precise focused ultrasound (FUS)
device that can be used on small animal models in preclinical research.

The FUS transducer, created in-house using a 3D printer, costs about
$80 to fabricate. It can be integrated with a commercially available stereotactic frame to precisely target a mouse brain. Results of
the work were published online in IEEE Transactions on Biomedical EngineeringFeb. 15 The device had several benefits, Chen said,
including achieving sub-millimeter targeting accuracy and having a
tunable drug-delivery outcome. In addition, using higher frequency FUS transducers decreased the BBB opening volume and improved the precision
of FUS-BBB opening in targeting individual structures in the mouse brain.

"We showed that under the same pressure level, a higher-frequency FUS transducer achieved a small drug delivery volume, improving the spatial precision of BBB opening compared with what has been achieved with lower- frequency transducers," Chen said.

To create the transducer, the team only needed to connect wires to
the electrodes on the elements. The rest of the parts were made on a
3D printer.

With the use of a stereotactic frame, her team was able to target the
exact location they wanted in the brain, which eliminated one of the
barriers to more widespread use of the FUS technique. Chen's team has
made the design available on Github.

"We expect this device could be manufactured by research groups without ultrasound background and used in various applications in preclinical
research with minimal training needed," Chen said.

The team used contrast-enhanced MRI to measure the BBB opening volume at different acoustic pressures and evaluated the drug delivery outcome using
a model drug. The device was shown to be very safe, with a microhemorrhage found in two mice at the highest tested acoustic pressures and no tissue
damage found in other groups.

Focused ultrasound uses ultrasonic energy to target tumors or tissue in
the brain. Once located, the researchers inject microbubbles into the
blood that travel to the targeted tissue then pop, causing small tears
of the blood-brain barrier. The ruptures allow drugs to be delivered
or biomarkers from a tumor to pass through the blood-brain barrier
and release into the blood. Chen and her lab have been perfecting the
technique in preclinical models for the past several years.

Chen said she hopes this device can reduce the barriers to the adoption
of the FUS technique by the broad research community.

========================================================================== Story Source: Materials provided
by Washington_University_in_St._Louis. Original written by Beth
Miller. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Zhongtao Hu, Si Chen, Yaoheng Yang, Yan Gong, Hong Chen. An
affordable
and easy-to-use focused ultrasound device for noninvasive and high
precision drug delivery to the mouse brain. IEEE Transactions on
Biomedical Engineering, 2022; 1 DOI: 10.1109/TBME.2022.3150781 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220222125057.htm

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