Microneedle treatment. Light microscopic images of bovine skin treated with microneedles of 200 μm (A) and 300 μm (B) needle lengths after topical administration of methylene blue solution for 6 hours; the arrows show the punctured areas with methylene blue penetration into deeper skin layers. C and D show histological images of perforated skin samples (C: 200 μm, D: 300 μm) after administration of methylene blue on the microneedle pretreated skin samples; the arrows show the punctured areas with methylene blue penetration into deeper skin layers. The bars represent 500 μm.
Stahl et al. BMC Pharmacology and Toxicology 2012 13:5 doi:10.1186/2050-6511-13-5