Renal epithelial monolayer formation on monomeric and polymeric catechol functionalized supramolecular biomaterials

Induction of a functional, tight monolayer of renal epithelial cells on a synthetic membrane to be applied in a bioartificial kidney device requires for bio-activation of the membrane. The current golden standard in bio-activation is the combination of a random polymeric catechol (L-DOPA) coating and collagen type IV (Col IV). Here the possibility of replacing this with defined monomeric catechol functionalization on a biomaterial surface using supramolecular ureido-pyrimidinone (UPy)-moieties is investigated. Monomeric catechols modified with a UPy-unit are successfully incorporated and presented in supramolecular UPy-polymer films and membranes. Unfortunately, these UPy-catechols are unable to improve epithelial cell monolayer formation over time, solely or in combination with Col IV. L-DOPA combined with Col IV is able to induce a tight monolayer capable of transport on electrospun supramolecular UPy-membranes. This study shows that a random polymeric catechol coating cannot be simply mimicked by defined monomeric catechols as supramolecular additives. There is still a long way to go in order to synthetically mimic simple natural structures.