title: Flexible control of cellular encapsulation, permeability, and release in a droplet-templated bifunctional copolymer scaffold.
abstract: Designing cell-compatible, bio-degradable, and stimuli-responsive hydrogels is very important for biomedical applications in cellular delivery and micro-scale tissue engineering. Here, we report achieving flexible control of cellular microencapsulation, permeability, and release by rationally designing a diblock copolymer, alginate-conjugated poly(N-isopropylacrylamide) (Alg-co-PNiPAM). We use the microfluidic technique to fabricate the bifunctional copolymers into thousands of mono-disperse droplet-templated hydrogel microparticles for controlled encapsulation and triggered release of mammalian cells. In particular, the grafting PNiPAM groups in the synthetic cell-laden microgels produce lots of nano-aggregates into hydrogel networks at elevated temperature, thereafter enhancing the permeability of microparticle scaffolds. Importantly, the hydrogel scaffolds are readily fabricated via on-chip quick gelation by triggered release of Ca2+from the Ca-EDTA complex; it is also quite exciting that very mild release of microencapsulated cells is achieved via controlled degradation of hydrogel scaffolds through a simple strategy of competitive affinity of Ca2+from the Ca-Alginate complex. This finding suggests that we are able to control cellular encapsulation and release through ion-induced gelation and degradation of the hydrogel scaffolds. Subsequently, we demonstrate a high viability of microencapsulated cells in the microgel scaffolds.
authors.affiliation: Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University , Beijing, China.
authors.forename: Qiushui
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Institute of Process Equipment, College of Chemical and Biological Engineering, Zhejiang University , Hangzhou, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.affiliation: School of Science, China University of Geosciences (Beijing) , Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University , Beijing, China.
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Lin