In vivo gene transfer to skin and wound by microseeding

Gene transfer to skin has many potential applications but lacks a safe, practical delivery method. This report presents a new technique, microseeding, for in vivo gene transfer to skin and wounds and for DNA-mediated vaccination. The plasmid DNA solution was delivered directly to the target cells of the skin by a set of oscillating solid microneedles driven by a modified tattooing device.

Skin and partial-thickness excisional wounds in pigs were microseeded with either hEGF expression plasmid or beta-galactosidase expression plasmid. Human EGF was also delivered by single injection or particle bombardment. hEGF expression in wound fluid and in target tissue was determined by ELISA with anti-hEGF-specific antibodies. Additionally, weanling pigs were microseeded with a hemagglutinin of swine influenza virus expression plasmid and production of anti-HA-specific antibodies was determined by blocking ELISA.

hEGF expression in microseeded partial thickness wounds (5664 pg/site) and skin sites (969 pg/site) peaked 2 days after transfection being four- to seven-fold higher than gene transfer by a single intradermal injection and two- to three-fold higher than particle-mediated gene transfer. The beta-galactosidase-expressing cells were detected in dermis and epidermis. Pigs microseeded with HA expression plasmid were protected from infection by the Swine influenza virus.

These results demonstrate that microseeding is a simple and effective method for in vivo gene transfer to skin and wounds and is more efficient than single injection and particle-mediated gene transfer.