Transdermal delivery of dextran using conductive microneedles assisted by iontophoresis

The combination of microneedles (MNs) and iontophoresis (ITP) can enhance the drug penetration in the skin. We previously demonstrated the enhanced delivery of small molecule lidocaine in dentistry by the conductive MNs assisted by ITP. However, the delivery of macromolecules is yet to be explored for this strategy. This study fabricates conductive MNs with polyaniline and hyaluronic acid, which is combined with ITP to deliver dextran macromolecules. This combination improves the penetration of dextran molecules (3-5 kDa, 150 kDa, and 500 kDa) to a depth of around 1536 μm in the agarose gel model. Compared to non-conductive MNs assisted by ITP or conductive MNs alone, conductive MNs assisted by ITP also improves dextran's penetration through the skin, fat, muscle, and cartilage.