Design, Development, and Testing of Polymeric Microblades: A Novel Design of Microneedles for Biomedical Applications

Abstract

Conventional microneedles (MNs) are designed as an array of micrometer-sized projections that can painlessly penetrate the skin. Fabrication of MN arrays can be costly and time-consuming; additionally, full penetration of an array of MNs with ten to thousands of projections into the skin may not be achievable. This paper reports a new design of MNs known as microblades (MBs) which consist of a singular microstructure. The single integrated design of the MBs reduces the fabrication cost and time, facilitates more effective penetration, and may pave the way for the scale-up manufacturing of MN devices. Different designs of MBs are fabricated by two-photon polymerization technique, followed by polydimethylsiloxane micromolding and soft embossing to create replicas. The mechanical integrity of the designs is determined by a series of compression tests. Skin insertion and drug diffusion studies are conducted using a custom-made applicator to insert the MBs into the porcine abdominal skin to demonstrate delivery of fluorescein tracer. MBs insertion and penetration capabilities and the diffusion of a model drug into a multi-layered human skin are demonstrated using finite element analysis and 3D diffusion models. The results demonstrate the functional capabilities of the MBs as an alternative to MN arrays.