Polymeric microneedle fabrication using a microinjection molding technique
- 823 Downloads
Polymeric microneedles fabricated by microinjection molding techniques have been demonstrated using Topas®COC as the molding plastic material. Open-channel microneedles with cross-sectional area of 100 μm × 100 μm were designed and fabricated on top of a shank of 4.7 mm in length, 0.6 mm in width, and 0.5 mm in depth. The tip of the microneedle has a round shape with a radius of 125 μm as limited by the drill used in fabricating the mold insert. The injection molding parameters including clamping force, shot size, injection velocity, packing pressure, and temperature were characterized in order to achieve best reproducibility. Experimentally, a fabricated microneedle was successfully injected into a chicken leg and a beef liver freshly bought from a local supermarket and about 0.04 μL of liquid was drawn from these tissues immediately. This new technology allows mass production of microneedles at a low cost for potential biomedical applications.
This project is supported in part by a grant from Korea Institute of Industrial Technology and an NSF award DMI0428884. The mold insert was fabricated in the UC-Berkeley Mechanical Engineering Machine Shop with the assistance of Mr. John Morton and the authors would like to thank Mr. Ron Wilson for taking SEM pictures.
- Brazzle D, Bartholomeusz R, Davies J, Andrade J, Van Wageman RA, and Frazier AB (2000) Active microneedles with integrated functionality. In: Proceedings of solid state sensor and actuator workshop, Hilton Head, pp 199–202Google Scholar
- Lin L, Pisano AP (1999) Silicon-processed microneedles. IEEE J Microelectromech Syst 8:178–184Google Scholar
- Menges G, Michaeli W, Mohren P (2001) How to make injection molds, 3rd edn. Carl Hanser Verlag, Munich, GermanyGoogle Scholar
- Rees H (2002) Mold engineering, 2nd edn. Carl Hanser Verlag, Munich, GermanyGoogle Scholar
- Stoeber B, Liepmann D (2000) Fluid injection through out-of-place microneedles. In: 1st annula international IEEE-EMBS special topic conference on microtechnologies in medicine and biology, Lyon, France, pp 224–228Google Scholar
- Stupar PA, Pisano AP (2001) Silicon, parylene, and silicon/parylene microneedles for strength and toughness. In: Proceedings of the 11th international conference on solid-state sensors and actuators (Transducers ‘01), Munich, GermanyGoogle Scholar