General fabrication of bioactive dissolving microneedles from whole grain seeds derived starch for transdermal...

Dissolving microneedles (DMNs) have gained increasing attraction for transdermal drug delivery. However, their manufacture is limited due to the lack of suitable fabricating materials. It is highly demanded to explore new materials for DMN preparation. Herein, we were the first to discover that natural grain powders were promising material candidates for DMN manufacture. MD was first used to determine the solvent to prepare microneedles. Then, mold method was used to fabricate five grain seed powders into microneedles. Afterwards, FTIR, XRD, MTT, live/dead assay and antioxidative assays (DPPH and Fenton) were applied to assess the chemical and biological properties of the microneedles. Finally, both in vitro and in vivo experiments were used to assess the transdermal effects of the microneedles. The results demonstrated that the microneedles had excellent biosafety with >90 % of living cells and <5 % of hemolysis rate. Also, the microneedles displayed up to 100 % eradication of free radicals, implying their good antioxidative capabilities. The transdermal study demonstrated that the microneedles could pierce mouse skins and undergo completely and fast dissolving in the skin as quickly as 30 s. This work will motivate more attempts to develop novel transdermal microneedles from natural products for biological applications.