A new rapid-release SMA-activated micropump with incorporated microneedle arrays and polymeric nanoparticles for optimized transdermal drug delivery

Recent research in Transdermal drug delivery (TDD) systems has predominantly focused on microneedles (MNs) and nanoencapsulated drugs, which offer painless, gradual drug release but may not cater to quick-release drug demands. This study introduces an innovative approach to expedite the TDD process by merging a new rapid-release micropump, MNs, and nanoencapsulation into a modular framework. The fabrication and evaluation of a 3D printed shape memory alloy (SMA)-activated micropump combined with ibuprofen-loaded polymeric nanoparticles delivered via integrated MNs is thereby discussed. The system utilizes an SMA spring wire to actuate a loaded spring which drives an elastic membrane into a chamber integrated with an array of stereolithography (SLA) 3D printed MNs, facilitating painless injection into the dermis layer of the skin. The MNs array is optimized with finite element analysis (FEA) to minimize discomfort from the needles while maximizing the drug load into the skin. The system's performance is characterized through high-speed camera imaging, and an average membrane speed of 0.28 m/s is developed. The system's effectiveness is finally evaluated via a short time frame (5 minutes) ex vivo skin deposition experiment using Franz diffusion cells and rat skin, revealing almost twice the ibuprofen deposition in skin layers with polymeric nanoparticles compared to an untreated solution. The rapid response and demonstrated efficacy of this concept aims to provide a framework for potentially extending this application for transdermal insulin injection.