Medical Design Briefs - August 2023 - 23

Drug Delivery
Implantable Drug-Delivery System Powered by Light
The system is triggered by external light sources.
A
team of scientists - led by Yamin Zhang, PhD, and Colin
Franz, MD, PhD, at Shirley Ryan Ability Lab and John
Rogers, PhD, at Northwestern University - has developed
novel technology with the potential to change the future
of drug delivery.
The device developed represents the first implantable
drug-delivery system that is triggered by external light sources
of different wavelengths, and not by electronics. It also is the
first to be absorbable by the body (avoiding surgical extraction)
while still allowing active control and programming by the operator
(e.g., a doctor, nurse, or patient). A study highlighting
the device has been published in the Proceedings of the National
Academy of Sciences (PNAS).
" This technology represents a breakthrough addressing
shortfalls of current drug-delivery systems - one that could
have important and sweeping implications for everything from
the opioid epidemic to how cancer treatments are precisely delivered, "
says Colin Franz, MD, PhD, physician-scientist at Shirley
Ryan AbilityLab.
Current implantable drug-delivery systems are used to treat
medical conditions ranging from chronic pain and muscle
spasticity to cancer and diabetes. Passive systems enable gradual
release of drugs and don't require extraction at the end of
their use, but they cannot be actively controlled by the user
(e.g., turning drug delivery off, up, or down). Conversely, active
systems that allow programmable drug release require
power supplies and electronic parts, and eventually require a
second surgery for device extraction.
To test this novel technology, researchers surgically implanted
it into the right sciatic nerve of individual rats. Each device
contained three drug reservoirs filled with lidocaine, a common
nerve-pain-blocking drug. Then, three LEDs were placed
over the implantation sites to trigger release of the drug. Subsequent
testing showed marked pain relief among the rats. Moreover,
researchers were able to achieve different patterns of pain
relief depending on the LED color-light sequencing.
" We found this approach to be an effective, safe, and nonaddictive
alternative to systemically delivered pain medications, "
says Northwestern University's John Rogers, PhD. " Additionally,
it can be scaled. Although we used a combination of
three LEDs in our proof-of-concept testing, moving forward we
can potentially increase it up to 30 different LED wavelengths,
offering many more programs for pain relief. "
In future studies, the scientific team will review various safety
elements prior to seeking U.S. Food and Drug Administration
(FDA) clearance for human clinical trials.
" This technology has many promising implications in rehabilitation
medicine and beyond, and the collaboration among physicians,
material scientists, and biomedical engineers at Shirley
Ryan AbilityLab and Northwestern University is rapidly accelerating
clinically relevant discoveries, " says Dr. Franz, who also is an assistant
professor of physical medicine and rehabilitation and neurology
at Northwestern University Feinberg School of Medicine.
This work was supported by the Kimberly K. Querrey and
Louis A. Simpson Institute for Bioelectronics at Northwestern
University and a generous philanthropic gift from the family of
Belle Carnell, which established a regenerative neurorehabilitation
fund for precision medicine in Dr. Franz's lab.
For more information, contact John Rogers at jrogers@
northwestern.edu or visit www.northwestern.edu or www.
sralab.org.
Read more about the science of
self-powered technology.
Light
Sciatic
nerve
receiver
Sciatic
nerve
1cm
Sciatic nerve
Illustration showing the placement of a device with gates adjacent to the sciatic nerve of a rat and an image of an implanted device. (Credit: PNAS)
Medical Design Briefs, August 2023
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Medical Design Briefs - August 2023

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