Spin coating of polymer solution on polydimethylsiloxane mold for fabrication of microneedle patch

- The spin coating process was proposed and demonstrated to fabricate polymer microneedle patch.
- Effect of adding bovine serum albumin in polymer solution on spin coating was examined.
- The mechanism of filling cavities to form microneedles was provided.
- Characterization of the microneedles was conducted through mechanical measurement and skin insertion test.

Since 1990 s, research and development of microneedles (MNs) for transdermal drug delivery (TDD) have been receiving great attention. Among various kinds of MNs, the dissolvable polymer MNs provide several attractive merits such as biocompatibility, biodegradability, and active and controlled release of drugs. Currently, the widely practiced approaches, i.e. evaporation and centrifugation, suffer from either relatively long processing time or tedious procedure. This project aims to develop and validate a new method, i.e. spin-coating process, to fabricate polymer MNs in a relatively simple and fast manner. First, the polydimethylsiloxane (PDMS) daughter mold replicated from the MNs array was used and bonded to the cleaned glass slide. The assembly was then placed on the spin coater, followed by dispensing the polymer solution and switching on the spin coater. It was found that, addition of trace amount of bovine serum albumin (BSA) in the polymer solution will facilitate formation of polymer film on PDMS surface by spin coating. Moreover, with the simple setup and procedures, the dissolvable polymer MNs with needle height up to 300 µm can be obtained.

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