A novel base for silicon nanoneedle patches can deliver doses of biomolecules directly into cells in a minimally invasive way, according to a study published online ahead of print in the journal Science Advances (Nov. 9, 2018). The new technology may potentially be used in intracellular, intradermal, and intramuscular nanoinjection of biomolecules into various types of biological cells and tissues.
“This means that eight or nine silicon nanoneedles can be injected into a single cell without significantly damaging a cell. So, we can use these nanoneedles to deliver biomolecules into cells or even tissues with minimal invasiveness,” said Dr. Chi Hwan Lee, PhD, an assistant professor in Purdue University’s Weldon School of Biomedical Engineering and School of Mechanical Engineering, in West Lafayette, Ind., in a press release.
Unlike commercially available patches that are constructed on a rigid and opaque silicon base, this new design features an elastomer base that is flexible and translucent. This design better matches the soft and curvilinear structures of biological tissues. As such, the nanoneedle patches are more comfortable and can be left between skin, muscles, or tissues for a longer period of time.
A diagram showing the basic characteristics of the microneedle patches. (C) Scanning electron microscope images of MCF7 cells on a representative silicone microneedle patch at 24 hours after nanoinjection. Scale bar, 10 μm. Arrows highlight the deformed patches by cell deformations. (D) Time-lapsed live differential interference contrast (DIC) images of HDF cells that interacted with the
microneedle patches at the bottom. Scale bar, 10 μm.
Photo from Science Advances.
“[The physical properties of previous patches] are exactly opposite to the flexible, curved and soft surfaces of biological cells or tissues,” said Dr. Lee. “To tackle this problem, we developed a method that enables physical transfer of vertically ordered silicon nanoneedles from their original silicon wafer to a bio-patch. This nanoneedle patch is not only flexible but also transparent, and therefore can also allow simultaneous real-time observation of the interaction between cells and nanoneedles.”
In the device created by Dr. Lee and his colleagues, the nanoneedles are partly embedded in a thin flexible and transparent bio-patch that can be worn on the skin and can deliver controlled doses of biomolecules. The investigators plan to develop the patch’s functionality to act as an external skin patch that can lower the pain, invasiveness, and toxicity associated with long-term drug delivery.
In future versions of the mechanism, the researchers plan to test the operational validity of the patch’s capabilities in monitoring cellular electrical activity or treating cancerous tissue.