Covalently Adaptable Elastin‐Like Protein–Hyaluronic Acid (ELP–HA) Hybrid Hydrogels with Secondary Thermoresponsive Crosslinking for Injectable Stem Cell Delivery. (19th May 2017)

• Record Type: Journal Article
• Authors: Wang, Huiyuan; Zhu, Danqing; Paul, Alexandra; Cai, Lei; Enejder, Annika; Yang, Fan; Heilshorn, Sarah C.
• Is Part Of: Advanced functional materials. Volume 27:Number 28(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-05-19
• Subjects: dynamic covalent chemistry -- elastin‐like protein (ELP) -- injectable hydrogels -- mesenchymal stem cells -- secondary crosslinking; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201605609
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract : Shear‐thinning, self‐healing hydrogels are promising vehicles for therapeutic cargo delivery due to their ability to be injected using minimally invasive surgical procedures. An injectable hydrogel using a novel combination of dynamic covalent crosslinking with thermoresponsive engineered proteins is presented. Ex situ at room temperature, rapid gelation occurs through dynamic covalent hydrazone bonds by simply mixing two components: hydrazine‐modified elastin‐like protein (ELP) and aldehyde‐modified hyaluronic acid. This hydrogel provides significant mechanical protection to encapsulated human mesenchymal stem cells during syringe needle injection and rapidly recovers after injection to retain the cells homogeneously within a 3D environment. In situ, the ELP undergoes a thermal phase transition, as confirmed by coherent anti‐Stokes Raman scattering microscopy observation of dense ELP thermal aggregates. The formation of the secondary network reinforces the hydrogel and results in a tenfold slower erosion rate compared to a control hydrogel without secondary thermal crosslinking. This improved structural integrity enables cell culture for three weeks postinjection, and encapsulated cells maintain their ability to differentiate into multiple lineages, including chondrogenic, adipogenic, and osteogenic cell types. Together, these data demonstrate the promising potential of ELP–HA hydrogels for injectable stem cell transplantation and tissue regeneration. Abstract : Shear‐thinning and self‐healing hydrogels containing protein‐engineered elastin‐like protein and hyaluronic acid are fabricated through dynamic covalent crosslinking, followed by thermoresponsive physical crosslinking for reinforcement and enhanced stability. These hydrogels have highly tunable stiffness, provide delivered stem cells significant mechanical protection, and maintain the cells after delivery in a 3D environment that supports further differentiation.