Low-Cost Fabrication of Hollow Microneedle Arrays Using CNC Machining and UV Lithography

In order to produce disposable microneedles for blood-collection devices in smart homecare monitoring systems, we have developed a simple low-cost scalable process for mass fabrication of sharp-tipped microneedle arrays. The key feature in this process is a design of computer numerical control-machined aluminum sample (CAS). The inclined sidewalls on the CAS enable microfabricated traditional-shaped microneedles (TMNs) to be produced in the desired shape. This process provides significant advantages over other methods that use inclined lithography or anisotropic wet etching. TMNs with a length of 1510 μm, a hollow diameter of 120 μm, and the tip radius of 16 μm were successfully fabricated. Theoretical study and practical measurements of fracture force verified the improved mechanical strength of TMNs for safe skin insertion. In addition, the penetration tests on cadaver pork skin demonstrated that the TMNs could pierce the pork skin without breaking, and create the transport conduits through microneedle lumens.