Mission impossible: Dermal delivery of growth factors via microneedling.

The clinical application of transdermal delivery has been limited to lipophilic drugs with a molecular weight of less than 500 Da. The development of polymeric microneedles enabled the transdermal delivery of larger proteins and drugs. Extensive research has been conducted on the molecular size, solubility, pH, concentration, and polarity of transdermal delivery; however, the maximal molecular weight for transdermal microneedle delivery has not been established. Clinicians often use simple microneedles to deliver high molecular weight growth factors of platelet-rich plasma across the skin; thus, we set out to explore the feasibility of delivering growth factors through microneedling. In this communication, we present histological evidence that microneedling do not enhance transdermal delivery of growth factors and thus provide no clinical benefit.