Biodegradable microneedle mesh to deliver heterogeneous drugs for vascular diseases

Unlike microneedles for transdermal drug delivery, vascular microneedle devices need to be flexible and deformable to be installed around blood vessels or anastomosis sites that have complex shapes and curvatures. Although previous work has fabricated microneedles on flexible substrates, the flexible substrates are non-biodegradable and have limited bending curvatures. In this work, we developed a microneedle mesh for vascular drug delivery. A biodegradable polymer melt was transferred to individual micro cavities in a mold via a droplet attached at the end of a heated metal pillar. Then, pressure was gently applied to facilitate the filling of the micro cavity with the polymer melt. This was followed by a localized joining of microneedles to a surgical mesh. Vascular tissue insertion characteristics of a microneedle mesh was analyzed with a leporine abdominal aorta. Furthermore, the controlled release of two model drugs at different release rates from a microneedle mesh was demonstrated.