Development of a Fully Synthetic Corneal Stromal Construct via Supramolecular Hydrogel Engineering

Abstract

Recent advances in the field of ophthalmology show great potential in the design of bioengineered constructs to mimic the corneal stroma. Hydrogels based on synthetic supramolecular polymers, are attractive synthetic mimics of the natural highly hydrated corneal stroma. Here, a fully synthetic corneal stromal construct is developed via engineering of an injectable supramolecular hydrogel based on ureido‐pyrimidinone (UPy) moieties. The hydrogel displays a dynamic and tunable behavior, which allows for control of biochemical and mechanical cues. Two hydrogels were developed, a fully synthetic hydrogel functionalized with a UPy‐cRGD additive, and a hybrid hydrogel based on UPy‐moieties mixed with collagen type I fibers. Both hydrogels supported cell encapsulation and associated cellular deposition of extracellular matrix (ECM) proteins after 21 days. Excitingly, the hydrogels support the activation of isolated primary keratocytes into stromal fibroblasts as well as the differentiation towards more quiescent corneal stromal keratocytes, demonstrated by their characteristic long dendritic protrusions and a substantially diminished cytokine secretion. Furthermore, cells survived shear stresses during an injectability test. Together, these findings highlight the development of an injectable supramolecular hydrogel as a synthetic corneal stromal microenvironment able to host primary keratocytes.This article is protected by copyright. All rights reserved

Collagen type I mimicking peptide additives to functionalize synthetic supramolecular hydrogels

“…4 B). Both the synthetic hydrogel functionalized with UPy-cRGD as well as the hybrid hydrogel mixed with natural collagen type I were used as reference hydrogels [ 51 ]. Previous work demonstrated only minor differences in mechanical characteristics as a result of the incorporation of an UPy peptide additive, therefore no additional rheological measurements were performed in this study (SI, Fig.…”

“…Due to the molecular design of the UPy-Glycine it is expected that the glycols’ non-fouling properties are shielded from exposure, while the glycine-amide groups are assumed to be presented to the cells. Upon addition of the UPy-PEG 10K -UPy interfiber cross-links are formed, resulting in the formation of a hydrogel [ 34 , 50 , 51 ]. Two control hydrogels were incorporated in this study as a reference, namely a synthetic UPy hydrogel functionalized with UPy-cRGD ( Fig.…”

“…1 D) and a hybrid hydrogel based on a mixture of UPy molecules and collagen type I ( Fig. 1 E) [ 51 ]. While both peptide additives are designed to mimic collagen type I, we assume only the UPy-GFOGER additive will fold into a supramolecular aggregate comprising a triple-helical conformation.…”