Skin Deep Problems
A flexible, synthetic patch helps eliminate the toxicity and invasiveness associated with long-term drug delivery
In most cases, conventional drug delivery works very well, but what about when first-pass metabolism interferes with the drug to render it useless? Or when patients simply refuse to swallow tablets? Injectables are also not immune to problems, given that a number of patients may be needle-phobic.
For many years, there has been intense discussion in the industry about the benefits of transdermal delivery. One common approach to dermal drug delivery is the use of silicon nanoneedle patches, but while these do show potential, they can only be used on a short-term basis. Commercially available patches are often rigid and may cause damage to the tissues around the site of injection. Chi Hwan Lee, Assistant Professor of Biomedical Engineering at Purdue University, along with his colleagues, has developed a flexible, transparent patch capable of delivering drugs to a target site without causing discomfort to the patient. The nanoneedles on the patch reduce the invasiveness and toxicity associated with long-term drug delivery (1).
“Our design really focused on making transdermal patches practical for use over extended periods. The flexibility of the silicon nanoneedles allows for injection on curved surfaces, such as the fingers, neck or elbow. In fact, several of them can be injected into a single biological cell at the nano-resolution scale in a minimally invasive manner,” Lee explains. “Another feature that sets the patch apart from traditional nanoneedle patches is its transparency. This means that real-time interactions between cells and nanoneedles can be observed. Previously, patches were opaque, limiting our ability to monitor the extent of cellular damage that was occurring.”
The team is testing the operational validity of the patch for treating cancerous tissues and monitoring electrical activity in cells. They are also looking at tweaking the system in other ways. “We recognize that while our patch minimizes tissue damage in comparison to previous technologies, it doesn’t completely mitigate the problem. We hope to reduce the size of the needle tips on our patches to help avoid any unnecessary tissue damage,” says Lee.
- CH Lee et al., “Flexible elastomer patch with vertical silicon nanoneedles for intracellular and intratissue nanoinjection of biomolecules,” Science Advances, 11 (2018).
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