Nanoparticle popsicle: Transdermal delivery of nanoparticles using polymeric microneedle array

A number of nanoparticles are currently applied for medical or medicinal research fields through conjugating with drugs or bio-molecules such as DNA, RNA, and peptides. There are three distinct ways to deliver nanoparticles into animal and human bodies: injection, feeding, and transdermal administration. We fabricated a polymeric microneedle array carrying nanoparticles on the end-tip of needles for an efficient delivery of functional nanoparticles through the skin. The polymeric microneedles with a length ranging from 600 to 1,000 μm were casted out using laser-printed PDMS (polydimethylsiloxane) molds where the 50 nm silica or polystyrene nanoparticles had been filled by centrifugation. When the microneedle array was applied to the porcine cadaver skin, nanoparticles were quickly and stably dispersed in the hypodermis. Microneedle array conjugated with nanoparticles has a potential for an alternative method to deliver cosmetic or pharmaceutical materials into human skin locally without professional procedures.