DLP 3D Printed ``Intelligent'' Microneedle Array ( iμNA) for Stimuli Responsive Release of Drugs and Its in Vitro and ex Vivo Characterization

We demonstrate a new fabrication technology to realize “intelligent”, transdermal, minimally invasive microneedle array ( i $\mu $ NA) by crosslinking a hydrogel, Polyethylene Glycol Diacrylate (PEGDA) by photo-polymerization using Digital Light Processing (DLP) based 3D printing. The photo-polymerization conditions have been optimized so that the mutually exclusive requirements of excellent mechanical strength while retaining hydrogel properties of PEGDA are met which would allow swelling/delivery of therapeutic cargo of diclofenac sodium via diffusion. An array having 100 microneedles arranged in a $10\times 10$ array was successfully 3D printed which efficiently penetrated human skin during ex vivo characterization. In vitro drug release studies demonstrated that the PEGDA based i $\mu $ NA behaves as a stimuli responsive device showing distinct release characteristics from external stimuli such as temperature and pH. [2020-0133]