(531e) Injectable and Degradable Zwitterionic Polycarboxybetaine Hydrogels

Hydrogels constructed from zwitterionic polymers and crosslinkers based on polycarboxybetaine (pCB) offer unique advantages for drug delivery and tissue engineering applications. Because of their strong hydration and resistance to nonspecific interactions, they can act as scaffolds to maintain stem cell pluripotency, control stem cell self-renewal or precisely direct their fate [1], mitigate the foreign body reaction to implanted materials [2] and demonstrate self-healing abilities [3]. To realize injectable pCB hydrogels for these applications, we have developed chemical and physical crosslinking strategies that allow rapid in situ gel formation under physiological conditions and reversible viscoelastic changes. In one strategy, we exploited â??zwitterionic fusionâ? to form injectable hydrogels with dynamic mechanical properties that can reversibly change and self-heal in response to shear [3]. Several approaches to incorporate degradability into pCB hydrogels will be discussed and compared. Furthermore, cells, biologics or drug-loaded particles can be entrapped in these injectable zwitterionic hydrogels, which act as effective carriers and depots.

[1] T. Bai, F. Sun, L. Zhang, A. Sinclair, S. Liu, J.R. Ella-Menye, Y. Zheng and S. Jiang, "Restraint of the Differentiation of Mesenchymal Stem Cells by a Nonfouling Zwitterionic Hydrogel", Angewandte Chemie. Vol. 53, pp 12729-12734 (2014)

[2] L. Zhang, Z. Cao, T. Bai, L. Carr, J.R Ella-Menye, C. Irvin, B. Ratner, S. Jiang, "Zwitterionic hydrogels implanted in mice resist the foreign-body reaction", Nature Biotechnology. Vol. 31, pp 553-556 (2013)

[3] T. Bai, S. Liu, F. Sun, A. Sinclair, L. Zhang, Q. Shao and S. Jiang, "Zwitterionic fusion in hydrogels and spontaneous and time-independent self-healing under physiological conditions", Biomaterials. Vol. 35, pp 3926-3933 (2014)