Speaker
Description
"Recent works on dynamic hydrogels, using non-covalent and/or dynamic covalent linkages, have shown that dynamic and spatial-temporal complex materials are promising step-towards the recapitulation of extracellular matrix (ECM) functionality and structure 1-5. However, the uncontrollable network properties across timescales make these dynamic hydrogels insufficient for fully recapitulating the native ECM. In order to control the mechanical and biological cues provided to cells through the biomaterial at each stage, we investigated the combination of two networks: one dynamic covalent cross-linked, and the other a photo-responsive network. The second network based on light-responsive linkages could enable reversible control of cross-linking degree with spatiotemporal resolution. Here, we first synthesized photo-responsive polymers based on polyethylene glycol with a coumarin derivate as an end group. After optimizing the synthetic protocol, the coupling-cleavage transition of 4-arm-polyethylene glycol coumarin (4PC) and 2-arm-polyethylene glycol coumarin (2PC) was determined by UV-Vis spectroscopy. The dimerization of coumarin takes place by irradiation above 300 nm, while the cleavage of the dimers is below 300 nm. Once the photo-responsive polymers were characterized, double network (DN) hydrogels were developed by combining a dynamic and a static photo-responsive cross-linked network. We investigated the combination of oxidized alginate cross-linked by Schiff-base reactions (OA, dynamic network) and photo-cross-linkable polymers (2PC and 4PC, photo-responsive network). The DN hydrogels showed self-healing properties and their mechanics can be modulated by UV irradiation. Rheological characterization was carried out to further investigate the reversibility of the hydrogel properties by UV irradiation. These biomaterials are promising for remotely providing to cell mechanical and biological cues and, hence, modulating cell response.
References
1. Diba, M, et al., Engineering the Dynamics of Cell Adhesion Cues in Supramolecular Hydrogels for Facile Control over Cell Encapsulation and Behavior. Adv Mater 2021, 33 (37), e2008111.
2. Morgan, FLC; Moroni, L; Baker, MB, Dynamic Bioinks to Advance Bioprinting. Adv Healthc Mater 2020, e1901798.
3. Xu, J; Liu, Y; Hsu, SH, Hydrogels Based on Schiff Base Linkages for Biomedical Applications. Molecules 2019, 24 (16).
4. Rosales, AM, et al., Hydrogels with Reversible Mechanics to Probe Dynamic Cell Microenvironments. Angew Chem Int Ed Engl 2017, 56 (40), 12132-12136.
5. Ooi, HW, et al., Hydrogels that listen to cells: a review of cell-responsive strategies in biomaterial design for tissue regeneration. Mater. Horiz. 2017, 4 (6), 1020-1040."
20941835924
