Centrifugal Lithography: Self-Shaping of Polymer Microstructures Encapsulating Biopharmaceutics by Centrifuging Polymer Drops.

Polymeric microstructures encapsulating biopharmaceutics must be fabricated in a controlled environment to preserve the biological activity. There is increasing demand for simple methods designed to preserve the biological activity by utilizing the natural properties of polymers. Here, the paper shows that centrifugal lithography (CL) can be used for the fabrication of such microstructures in a single centrifugation, by engineering the self-shaping properties of hyaluronic acid (HA). In this method, HA drops are self-shaped into hourglass-microstructures to produce two dissolving microneedles (DMN), which facilitate transdermal delivery via implantation on the skin. In addition, tuberculin purified protein derivatives are encapsulated into HA DMNs under refrigerated conditions (4 °C) during CL. Therefore, the tuberculin skin test (TST) with the DMNs indicates minimal damage, as opposed to the case of TST with traditional hypodermic needles. These findings on the fabrication of polymeric microstructures with biopharmaceutics may trigger the development of various biomedical devices and therapies.