Transdermal drug delivery is a very popular and convenient approach for various therapies such as pain management, pregnancy prevention, smoking cessation, and immunotherapy. However, not all of pharmaceuticals can successfully pass through the skin. The stratum corneum on the surface of skin acts as the forefront of the defense mechanism. It prevents our body from the environmental substance like gastrointestinal tract and lung with the permeable epithelia regulating what enters the body. Therefore, how to enhance the efficiency of transdermal delivery system including breaking the skin barriers without serious damage is a great challenge. Microneedle is a good solution which can reach a minimal invasive and dramatically increase skin permeability. Such technologies will cause reversible microchannels in the skin.
Here, we propose 3D printing technologies to fabricate the mold of microneedles, which facilitate customization and overcome the geometries from individual differences. Silk protein and polyvinyl alcohol (PVA) are used as the materials of matrix for high mechanical strength and rapid dissolvable abilities. Microneedles also equip with mesoporous superparamagnetic iron oxide nanoparticles (SPIONs) in the tip of microneedle patch for the drug delivery system. After the insertion of the patch to the skin, the supports dissolve and leave SPIONs leading sustain drug release. Furthermore, magnetic nanoparticles are able to be triggered under high frequency magnetic field (HFMF). In this way, the drugs will release on demand and simultaneously induce the thermotherapy.