Degradable and biocompatible hydrogels bearing a hindered urea bond
2017
YingThese authors contributed equally., Hanze | YenCurrent address: Chemical Biology and Therapeutics, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, 02139, USA. Jonathan | Wang, Ruibo | Lai, Yang | Hsu, Jer-Luen-Aaron | Hu, Yuhang | Cheng, Jianjun
A hindered urea bond (HUB), recently reported as a new type of dynamic chemical bond, can be facilely constructed by mixing an isocyanate and a hindered amine. Here, we report the use of the HUB in the design of degradable hydrogel materials for applications of stem cell encapsulation and delivery. Polyethyleneglycol (PEG) diamine was end-capped with a HUB and an allyl group in a one-pot synthesis. The resulting polymer was cross-linked to form a hydrogel under UV with the addition of a 4-arm PEG thiol and a photoinitiator. The degradation properties of the hydrogels were confirmed with NMR, GPC, weight loss, and protein release studies. We found that the degradation kinetics is dependent on the size of the N-substituents, and the one with the tert-butyl group shows complete degradation within 2 days. The new hydrogel materials were also demonstrated to be biocompatible with hMSCs, and the cell release kinetics can be facilely tuned over 5 days.
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