UV-assisted punching of microgel shapes for oral biomacromolecule delivery

Hydrogel based carriers have been predominantly investigated to combat the prominent challenges faced by oral biomacromolecule delivery. Several micromolding, microfluidic and photolithographic techniques have been described for the fabrication of non-spherical hydrogel based microcarriers. However, these techniques are unsuitable for loading biomacromolecules as integral part of the fabrication process due to the use of high temperatures, solvents and multiple processing steps. Here, we introduce UV-assisted punching as a novel two-step fabrication technique for the development of biocompatible microgel shapes for oral drug administration. Poly-ethylene glycol (PEG) microgel shapes with lateral dimensions of 25–100 μm and a height of 25 μm were fabricated on a flexible poly vinyl alcohol (PVA) substrate with a robust cycloolefin polymer (COP) stamp. The proposed process uses UV-initiated crosslinking of aqueous solutions at ambient temperatures, thereby providing a highly attractive method for the fabrication of biomacromolecule loaded hydrogel based carriers. For the proof-of-concept, the microgel shapes were loaded with the fluorescently labelled model biomacromolecule bovine serum albumin without any additional steps. The successful loading is demonstrated by fluorescence microscopy. In vitro studies are performed to quantify the macromolecular content and the release profile associated with the fabricated microgel shapes.