ISBN 978-3-8439-5815-8

978-3-8439-5815-8, Reihe Mikrosystemtechnik

Shubham Tiwari
Surface Engineering by Hydrogel Transfer Printing & its Advances in Biomedical Applications

280 Seiten, Dissertation Albert-Ludwigs-Universität Freiburg im Breisgau (2026), Softcover, B5

Zusammenfassung / Abstract

Coating materials with hydrogel layers is important for the performance of many modern biomedical materials; however, it proves frequently difficult on substrates with complex, non-planar topologies. We introduce a hydrogel transfer printing technique using a special paper and a C-H insertion reaction (CHic). The paper acts as a flexible transfer agent and has a hydrophobic and a hydrophilic side. When a photoreactive hydrogel precursor is deposited on its hydrophobic side, which is then placed on the target surface, adding a small amount of water to the hydrophilic side releases the hydrogel precursor and facilitates smooth transfer onto the desired substrate. After removing the transfer paper, brief UV illumination activates the deposited photopolymer, leading to cross-linking and covalent attachment of the layer to the substrate surface via CHic. We demonstrate the attachment of these hydrogels to substrates with varying, complex topologies, which allows the deposition of hydrogel layers with high accuracy and uniformity, as well as excellent underwater adhesion.

Later, we evaluated the stability, biocompatibility, and adherence of a protein-repellent hydrogel patch, deposited via transfer printing to prevent sclero-conjunctival adhesion and scar formation to improve the surgical treatment of glaucoma, a chronic progressive degeneration of the optic nerve, and a leading cause of blindness. After successful in-vitro studies, the hydrogel was investigated in-vivo in a rabbit model to assess its attachment to scleral tissue under physiological conditions and to characterize the ocular tissue response to the material as a foreign body. Furthermore, pharmacological treatments commonly used during trabeculectomy were examined for their capacity to reduce hydrogel-associated inflammation and support postoperative tissue recovery.