A gene-coated microneedle patch based on industrialized ultrasonic spraying technology with a polycation vector to...

A coated microneedle patch is a reliable way to load gene on a surface as a transdermal gene delivery platform. But there are many limitations to the traditional methods to fabricate a coated microneedle patch, such as the fact that they are time consuming or the difficulty in controlling the loading content. In this research, ultrasonic spraying technology, as an industrialized production method, was first used to fabricate a gene-coated microneedle patch. First, the p53 expression plasmid (p53 DNA) was ultrasonically sprayed on a polycaprolactone (PCL) microneedle patch (D@MNP). To promote the transfection efficiency, polycation polyethylenimine (PEI), as a vector, was then ultrasonically sprayed on D@MNP (P@D@MNP). From the experimental results, although two layers were sprayed step by step, no obvious stratification could be observed. The vector PEI interweaved with genes and inhibited the gene release profile, but it changed the released naked genes to positively charged complexes, which would promote gene transfection efficiency. In subsequent in vivo experiments, the anti-tumor efficacy of the "P@D@MNP treated group" could reach 84.7%, although it had the lowest gene release profile. In contrast, the anti-tumor efficacy of the "intravenous injection group" and "D@MNP treated group" was only 24.3% and 59.3%, respectively. Overall, P@D@MNP was a safe and efficient device to treat the subdermal tumor. Ultrasonic spraying technology provided an industrialized method to fabricate the coated microneedle patch as a transdermal gene/drug delivery platform.