Painless microneedles (MNs) inspired by limpet tooth with the capability of controllable drug delivery were produced by the magnetic field-assisted 3D printing (MF-3DP) process.
The hierarchical structures in limpet teeth, which are extraordinarily strong, result from aligned fibers of mineralized tissue and protein-based polymer reinforced frameworks. These structures provide design inspiration for mechanically reinforced composite. Here, a bioinspired MN array was fabricated using magnetic field-assisted 3D printing (MF-3DP). Micro-bundles of aligned iron oxide nanoparticles (aIOs) were encapsulated by polymer matrix during the printing process. The aligned magnetic nanoparticles showed promising enhanced compression resistance. The results reported here provide insights into how the geometrical morphology of MNs can be optimized for the painless drug delivery in clinical trials. It opens intriguing perspectives for designing MNs with sharp features and high mechanical strength based on the bioinspired hierarchical structures in the 3D-printed materials.
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