Feasibility Study of Carbon Nanotube Microneedles for Rapid Transdermal Drug Delivery
- PDF / 236,540 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 37 Downloads / 186 Views
Feasibility Study of Carbon Nanotube Microneedles for Rapid Transdermal Drug Delivery Bradley J. Lyon1, Adrianus I. Aria1, and Morteza Gharib1 1 Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, CA 91125, U.S.A. ABSTRACT We introduce a new approach for fabricating hollow microneedles using verticallyaligned carbon nanotubes (VA-CNTs) for rapid transdermal drug delivery. Here, we discuss the fabrication of the microneedles emphasizing the overall simplicity and flexibility of the method to allow for potential industrial application. By capitalizing on the nanoporosity of the CNT bundles, uncured polymer can be wicked into the needles ultimately creating a high strength composite of aligned nanotubes and polymer. Flow through the microneedles as well as in vitro penetration of the microneedles into swine skin is demonstrated. Furthermore, we present a trade study comparing the difficulty and complexity of the fabrication process of our CNT-polymer microneedles with other standard microneedle fabrication approaches. INTRODUCTION Microneedles are envisioned to provide a painless, self-administered alternative to standard hypodermic injection. Specifically, hollow microneedles allow for a delivery architecture that is more flexible than other microneedle designs such as solid microneedles, drug-coated microneedles, or dissolving microneedles. This is because hollow microneedles allow for variable delivery rate from rapid injection to emulate a hypodermic injection to slow steady delivery to mimic intravenous drug therapy. Additionally, since the hollow microneedle is designed to be inert with respect to the drug, many current drugs that are delivered into the skin can be directly used in the hollow microneedle architecture [1]. Previous studies on the fabrication of hollow microneedles have focused on top-down fabrication approaches using either silicon, metal, or glass. While these approaches have yielded functioning microneedles, their fabrication involves iterated etching or micromachining techniques that ultimately add complexity to the fabrication and limit industrial-scale application [1]. Here, we introduce a new perspective on forming hollow microneedles by fabricating microneedles using a bottom-up approach by using vertically-aligned carbon nanotubes (VACNTs). VA-CNTs are first used as a scaffold for forming the shape of the microneedle and then as a fiber component in a CNT-polymer composite to create a high strength material capable of penetrating the skin. By utilizing standard methods to grow VA-CNTs, including catalyst patterning and thermal chemical vapor deposition (CVD), we directly produce a hollow microneedle. In designing the CNT-polymer composite microneedle, the final product must achieve four mechanical objectives: (i) have high mechanical strength under compression to achieve skin penetration, (ii) conformally coat the VA-CNTs with polymer allowing the microneedle to retain its original shape from catalyst patterning, (iii) anchor microneedles to a common polymer base
Data Loading...
