Dataset Information

Visible-Light-Initiated Thiol-Michael Addition Polymerizations with Coumarin-Based Photobase Generators: Another Photoclick Reaction Strategy.

ABSTRACT: An efficient visible-light-sensitive photobase generator for thiol-Michael addition reactions was synthesized and evaluated. This highly reactive catalyst was designed by protecting a strong base (tetramethyl guanidine, TMG) with a visible-light-responsive group which was a coumarin derivative. The coumarin-coupled TMG was shown to exhibit extraordinary catalytic activity toward initiation of the thiol-Michael reaction, including thiol-Michael addition-based polymerization, upon visible-light irradiation, leading to a stoichiometric reaction of both thiol and vinyl functional groups. Owing to its features, this visible-light photobase generator enables homogeneous network formation in thiol-Michael polymerizations and also has the potential to be exploited in other visible-light-induced, base-catalyzed thiol-click processes such as thiol-isocynate and thiol-epoxy network-forming reactions.

SUBMITTER: Zhang X

PROVIDER: S-EPMC5176105 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

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Publications

Visible-Light-Initiated Thiol-Michael Addition Polymerizations with Coumarin-Based Photobase Generators: Another Photoclick Reaction Strategy.

Zhang Xinpeng X Xi Weixian W Wang Chen C Podgórski Maciej M Bowman Christopher N CN

ACS macro letters 20160122 2

An efficient visible-light-sensitive photobase generator for thiol-Michael addition reactions was synthesized and evaluated. This highly reactive catalyst was designed by protecting a strong base (tetramethyl guanidine, TMG) with a visible-light-responsive group which was a coumarin derivative. The coumarin-coupled TMG was shown to exhibit extraordinary catalytic activity toward initiation of the thiol-Michael reaction, including thiol-Michael addition-based polymerization, upon visible-light ir ...[more]

PMID: 28018752

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Project description:Photopolymerized biomimetic hydrogels with adaptable properties have been widely used for cell and tissue engineering applications. As a widely adopted gel cross-linking method, photopolymerization provides experimenters on-demand and spatial-temporal controls in gelation kinetics. Long wavelength ultraviolet (UV) light initiated photopolymerization is among the most popular methods in the fabrication of cell-laden hydrogels owing to its rapid and relatively mild gelation conditions. The use of UV light, however, still causes concerns regarding its potential negative impacts on cells. Alternatively, visible light based photopolymerization can be used to cross-link cell-laden hydrogels. The majority of visible light based gelation schemes involve photoinitiator, co-initiator, and comonomer. This multicomponent initiation system creates added challenges for optimizing hydrogel formulations. Here, we report a co-initiator/comonomer-free visible light initiated thiol-norbornene photopolymerization scheme to prepare modular biomimetic hydrogels suitable for in situ cell encapsulation. Eosin-Y was used as the sole initiator to initiate modular gelation between synthetic macromers (e.g., thiolated poly(vinyl alcohol) or poly(ethylene glycol)) and functionalized extracellular matrices (ECMs) including norbornene-functionalized gelatin (GelNB) or thiolated hyaluronic acid (THA). These components are modularly cross-linked to afford bioinert (i.e., purely synthetic), bioactive (i.e., using gelatin), and biomimetic (i.e., using gelatin and hyaluronic acid) hydrogels. The stiffness of the hydrogels can be easily tuned without affecting the contents of the bioactive components. Furthermore, the use of naturally derived biomacromolecules (e.g., gelatin and HA) renders these hydrogels susceptible to enzyme-mediated degradation. In addition to demonstrating efficient and tunable visible light mediated gelation, we also utilized this biomimetic modular gelation system to formulate artificial tumor niche and to study the effects of cell density and gel modulus on the formation of pancreatic ductal adenocarcinoma (PDAC) spheroids.

Dataset Information

Visible-Light-Initiated Thiol-Michael Addition Polymerizations with Coumarin-Based Photobase Generators: Another Photoclick Reaction Strategy.

Publications

Visible-Light-Initiated Thiol-Michael Addition Polymerizations with Coumarin-Based Photobase Generators: Another Photoclick Reaction Strategy.

Similar Datasets

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