Self-powered drug delivery systems: a medical breakthrough?

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New research presents the healthcare case for self-powered platforms for programmed drug delivery to enter the medical device space. Released on 8th March 2023 in the Proceedings of the National Academy of Sciences (PNAS), the study explores the potential of self-powered, light-controlled and bioresorbable platform technology.

A team of scientists from Northwestern University in the US have developed a novel technology. An active control device developed by the researchers may signal a pioneering new drug delivery technology that the researchers say may represent the future of drug delivery.

The technology differs from current drug delivery solutions due to its self-powered and resorbable nature. The system is absorbable by the body, which means no surgical extraction needs to occur. Despite its lack of surgery, a doctor, nurse, or patient can still control and programme the device.

Instead of electronics, external light sources of different wavelengths trigger the implantable drug delivery system. Current technology has batteries that need to be extracted when they are depleted. The scientists use a battery that is both resorbable and controlled by light of specific wavelengths.

By adding multiple compartments controlled by different light wavelengths and since it is resorbable, the drug release can be programmed with a device that does not require future extraction. Ultimately, the tech can enable patients and practitioners to ensure the precise delivery of medications through its light-led and resorbable system.

Tech-based drug delivery systems aim to enable individuals to understand and manage their conditions better. Today, medical practitioners use implantable drug delivery systems to treat various medical conditions, including chronic pain, muscle spasticity, diabetes, and cancer.

Research to date has explored the capabilities of triboelectric nanogenerators (TENG) in controlled drug release and delivery using electroporation and iontophoresis, along with the increasing relevance of self-powered drug delivery systems to reflect the rise of personalised healthcare.

The recently published study detailing the tech discovery provides new insights into self-powered drug delivery. “In the study, we demonstrate that the implant can be targeted to deliver the focused drug to a specific nerve (sciatic) for powerful blocking of pain signals, which is programmable and reversible,” says Dr Colin Franz, physician-scientist at Shirley Ryan AbilityLab, a research hospital specialising in acute rehabilitation.

In humans, the technology has the potential as a therapeutic nerve block to relieve neuropathic pain. Alternatively, it may deliver therapeutics to help promote nerve repair, Franz says, which is a future direction of Shirley Ryan AbilityLab’s research.

However, the technology also has much broader potential. “It could be used to deliver therapeutics to specific tissues like the brain or even a tumour depending on where it is implanted,” highlights Franz.

In its testing phase, the scientists surgically implanted the device into the right sciatic nerve of individual rats. Each device consists of three drug reservoirs filled with lidocaine, a common nerve-pain-blocking drug.

Next, researchers put light-emitting diodes (LED) over the implantation sites to trigger the drug’s release. Further testing following the implantation indicated marked pain relief among the subject rats. Also, depending on the sequencing of the LED colour light, the research team achieved different pain relief patterns, suggesting the systems’ relevancy in various conditions.

The programmed release of lidocaine adjacent to the sciatic nerves indicates its functionality in pain management, “an essential aspect of patient care that could benefit from the results”, demonstrated in the study, the scientists said. 

“This miniaturised and wirelessly programmed drug delivery device represents a significant advance over previously reported technologies, with potential for pharmacological treatment of a broad range of diseases,” the researchers said in the study.

Traditionally, the healthcare space has seen the development of passive drug delivery systems that work by enabling the gradual release of drugs. Similar to the self-powered system the scientists identified, the systems do not require surgical extraction at the end of their use. However, they cannot be actively controlled by the user.

Active systems, on the other hand, enable programmable drug release to require power supplies and electronic parts and require a second surgery for device extraction. Actively controlled systems represent an appealing alternative due to their abilities in user-defined programmability over discrete and timed releases. However, the need to support power supplies and wireless electronics and surgically extract devices after a period of use represents disadvantages that restrict and minimise its broad adoption.

The scientists’ device seeks to answer these requirements and fill a gap in current drug delivery systems. It strives to do this by using a light-controlled, bioresorbable platform that avoids the need for separate power supplies. Instead, it enables natural dissolution and clearance from the body post-treatment.

Before self-powered tech can enter the mainstream drug delivery space, developers need to overcome obstacles to adoption and implementation.

While a potential breakthrough discovery, it is nonetheless in the nascent stage of development. “The main hurdles are related to safety and regulatory issues,” says Franz. Highlighting the importance of this is the reminder that this research was a preclinical study on a rodent model.

As self-powered drug delivery is “a novel and highly advanced new material science approach”, Franz says before continuing, “for this to be adopted, we need to complete rigorous preclinical safety studies”. 

The device to enable the self-powered drug delivery will also need to be scaled up to reflect the dimensions of research subjects larger than a rodent. 

“Having to extract conventional biomedical devices at the end of their operating time and/or replace components or batteries is a limitation of current technology,” confirms Franz. 

The self-powered nature of the identified tech, along with other next-generation materials for wireless, provides healthcare practitioners with more effective drug delivery options to reflect consumers’ holistic needs.

“Resorbable drug delivery should be able to provide precise, programmable and less invasive drug delivery for conditions ranging from chronic pain or muscle spasticity to gene therapy or anti-cancer treatments,” adds Franz. 

Efforts to progress understanding and the potential of self-powered drug delivery systems further are underway. The researchers plan to review various safety elements in future studies before seeking US Food and Drug Administration (FDA) clearance for human clinical trials.