Document Detail

Visible light cured thiol-vinyl hydrogels with tunable degradation for 3D cell culture.
MedLine Citation:
PMID:  24021231     Owner:  NLM     Status:  Publisher    
We report here a synthetically simple yet highly tunable and diverse visible light mediated thiol-vinyl gelation system for fabricating cell-instructive hydrogels. Gelation was achieved via a mixed-mode step-and-chain-growth photopolymerization using functionalized 4-arm poly(ethylene glycol) as backbone macromer, eosin-Y as photosensitizer, and di-thiol containing molecule as dual purpose co-initiator/cross-linker. N-vinylpyrrolidone (NVP) was used to accelerate gelation kinetics and to adjust the stiffness of the hydrogels. Visible light (wavelength: 400-700nm) was used to initiate rapid gelation (gel points: ∼20 seconds) that reached completion within a few minutes. The major differences between current thiol-vinyl gelation and prior visible light mediated photopolymerization are that: (1) the co-initiator triethanolamine (TEOA) used in the previous systems was replaced with multifunctional thiols and (2) mixed-mode polymerized gels contain less network heterogeneity. The gelation kinetics and gel properties at the same PEG macromer concentration could be tuned by changing the identity of vinyl groups and di-thiol cross-linkers, as well as concentration of cross-linker and NVP. Specifically, acrylate-modified PEG afforded the fastest gelation rate, followed by acrylamide and methacrylate-functionalized PEG. Increasing NVP concentration also accelerated gelation and led to a higher network cross-linking density. Further, increasing di-thiol peptide concentration in the gel formulation increased hydrogel swelling and decreased gel stiffness. Due to the formation of thiol-ether-ester bonds following thiol-acrylate reaction, the gels degraded hydrolytically following a pseudo first order degradation kinetics. Degradation rate was controlled by adjusting thiol or NVP content in the polymer precursor solution. The cytocompatibility and utility of this hydrogel system were evaluated using in situ encapsulation of human mesenchymal stem cells (hMSC). Encapsulated hMSCs remained alive (>90%) throughout the duration of the study and the cells were differentiated down osteogenic lineage with varying degrees by controlling the rate and mode of gel degradation.
Yiting Hao; Han Shih; Zachary Muňoz; Arika Kemp; Chien-Chi Lin
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-9-7
Journal Detail:
Title:  Acta biomaterialia     Volume:  -     ISSN:  1878-7568     ISO Abbreviation:  Acta Biomater     Publication Date:  2013 Sep 
Date Detail:
Created Date:  2013-9-11     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101233144     Medline TA:  Acta Biomater     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2013. Published by Elsevier Ltd.
Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana-University Purdue-University Indianapolis, IN 46202, USA.
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