To realize the microliter scale of biofluid extraction, we additionally designed and fabricated a microneedle array that can puncture viscoelastic skin far less painlessly than the commercially available CGM’s. However, it has been shown that producing microneedles in a sharp, beveled form with complete control of the needle geometries is difficult to achieve with the current with microelectromechanical fabrication techniques, hindering the mass commercialization of microneedles in the medical field. Building upon this insight, we have created a novel fabrication system to create a silicon hollow microneedle in a repeatable, uniform, and controllable manner using micromachining and wet etch chemistries of silicon, as shown in Figure 1. In addition to developing the novel fabrication process, we performed a complete parametric study investigating the effects of variable such as chemical bath composition and silicon microneedle geometries [1]. Such experimental study has resulted in finding apparent reaction constants and diffusivity of silicon in acid chemistries, which is highly valuable for other numerous computational and design studies of etching silicon.
Reference:
[1] H. Kim, L. Theogarajan and S. Pennathur, "A repeatable and scalable fabrication method for sharp, hollow silicon microneedles", Journal of Micromechanics and Microengineering, vol. 28, no. 3, p. 035007, 2018. Available: 10.1088/1361- 6439/aaa6a8.