Microneedle patch integrated with a pumpless microfluidic chip for heterologous drug delivery

Microneedle (MN) devices, which consist of needles of micron size arranged on a small patch, have been considered minimally invasive, painless, and self-administered drug delivery systems where drugs are delivered through the transdermal route. In this study, a drug delivery system integrating an MN patch with a pumpless microfluidic (MF) device was proposed. Depending on the material, MNs exhibit various functions; herein, polymer MNs with a dissolution function were developed. Ideal MNs should exhibit high mechanical strength and stable geometries to permit skin penetration without breaking. Hence, polyvinylpyrrolidone (PVP)-M MNs with improved strength were developed. A porous coating method was employed to improve the drug delivery of the existing coated MNs. By coating a porous layer on the MN surface, its surface area increased, rendering advantages of increased drug storage for enhanced delivery. A pumpless MF device was developed to improve low drug storage due to the MN structural limitations. An external power source was not required to transmit pressure, and it was transmitted using the capillary force of filter paper. The drug stored in the microchannel was released to the outlet because of the applied pressure. It is a powerful device and exhibits a very simple structure that is easy to operate, flexible, and miniature. The results revealed that the proposed system has increased drug storage; as a result, drug delivery via this system was dramatically enhanced in comparison with that using the existing coated MNs. Moreover, dual drug delivery was also possible if the type of drug applied to the MNs and the device was different. The developed device is expected to contribute significantly to the future development in the biomedical field.