PEGDA/PVP Microneedles with Tailorable Matrix Constitutions for Controllable Transdermal Drug Delivery

Polymeric microneedles have attracted increasing interest for transdermal drug delivery owing to the unique advantages of minimal invasiveness, biocompatibility, biodegradability, and efficient drug-loading capacity. However, drug release from polymeric microneedles lacks controllability during transdermal administration. Herein, a poly(ethylene glycol) diacrylate/polyvinylpyrrolidone (PEGDA/PVP) microneedle patch with tailorable matrix constitutions is designed and fabricated using a two-step ultraviolet (UV) light-induced polymerization method. Scanning electron microscopic characterization reveals a non-uniform interior matrix of microneedles, resulting from the aggregation of PVP in the polymerized PEGDA matrix induced by UV irradiation. The fabricated microneedles are found to show sufficient mechanical strength for skin penetration and they can be removed intact after application. The controllable release property of rhodamine B (RhB)-loaded PEGDA/PVP microneedles is demonstrated in vitro by tuning the fraction of PVP content. The typical characteristics including initial burst and subsequent sustained release are attributed to the rapid dissolution of PVP and prolonged swelling of PEGDA, respectively. In addition, the microneedle insertion site can be completely recovered within 1 h on a porcine skin, indicating the minimally invasive feature of microneedle-mediated therapeutic delivery. This scalable microneedle platform may serve as a convenient and effective drug carrier for transdermal delivery of various pharmaceuticals under precise control.