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)

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 non-addictive 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 This email address is being protected from spambots. You need JavaScript enabled to view it. or visit www.northwestern.edu  or www. sralab.org  .

Read more about the science of self-powered technology below.

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Self-powered, Light-controlled, Bioresorbable Platforms for Programmed Drug Delivery

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    Medical Design Briefs Magazine

    This article first appeared in the August, 2023 issue of Medical Design Briefs Magazine (Vol. 13 No. 8).

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    Overview

    The document presents research on a novel self-powered, light-controlled, bioresorbable drug delivery system designed for programmable release of medications. This technology addresses the limitations of traditional drug delivery methods, which often require surgical extraction after use and lack precise control over release timing. The system utilizes a light-sensitive phototransistor that, when illuminated by an external light source, triggers a short circuit in an electrochemical cell. This process initiates the corrosion of a metal gate valve, allowing drugs stored in an underlying reservoir to be released passively into surrounding tissue.

    The design incorporates a wavelength-division multiplexing strategy, enabling independent control of multiple drug reservoirs within a single device. This allows for tailored drug release based on patient needs, which is particularly beneficial in pain management scenarios. In vivo studies demonstrated the system's functionality by successfully releasing lidocaine near the sciatic nerves in rat models, showcasing its potential for on-demand pain relief during and after surgical procedures.

    The document also discusses the biocompatibility and bioresorbability of the materials used in the device. Results indicated that the device does not elicit a strong immune response, and there were no significant adverse effects observed in animal models during the study period. The research highlights the importance of optimizing the choice of bioresorbable electrode materials to enhance the device's performance and safety.

    However, the study acknowledges certain limitations, such as the use of non-resorbable components like phototransistors and optical filters, which are not biodegradable. Ongoing research aims to develop fully resorbable components to overcome this challenge. Additionally, practical constraints exist regarding the number of reservoirs that can be independently controlled due to optical scattering and transmission bandwidth limitations.

    Overall, this research represents a significant advancement in drug delivery technology, with the potential to improve patient care through programmable, on-demand drug release systems. The findings suggest that such devices could revolutionize treatment protocols across various medical fields, offering a more effective and patient-centered approach to pharmacological therapy.