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Injectable Hydrogels with In Situ Double Network Formation Enhance Retention of Transplanted Stem Cells
Author(s) -
Cai Lei,
Dewi Ruby E.,
Heilshorn Sarah C.
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201403631
Subject(s) - self healing hydrogels , materials science , transplantation , biomedical engineering , regenerative medicine , in situ , ex vivo , in vivo , stem cell , biophysics , surgery , chemistry , microbiology and biotechnology , polymer chemistry , medicine , biology , organic chemistry
Stem cell transplantation via direct injection is a minimally invasive strategy being explored for treatment of a variety of injuries and diseases. Injectable hydrogels with shear moduli <50 Pa can mechanically protect cells during the injection process; however, these weak gels typically biodegrade within 1–2 weeks, which may be too fast for many therapeutic applications. To address this limitation, an injectable hydrogel is designed that undergoes two different physical crosslinking mechanisms. The first crosslinking step occurs ex vivo through peptide‐based molecular recognition to encapsulate cells within a weak gel that provides mechanical protection from injection forces. The second crosslinking step occurs in situ to form a reinforcing network that significantly retards material biodegradation and prolongs cell retention time. Human adipose‐derived stem cells are transplanted into the subcutaneous space of a murine model using hand‐injection through a 28‐gauge syringe needle. Cells delivered within the double‐network hydrogel are significantly protected from mechanical damage and have significantly enhanced in vivo cell retention rates compared to delivery within saline and single network hydrogels. These results demonstrate that in situ formation of a reinforcing network within an already existing hydrogel can greatly improve transplanted cell retention, thereby enhancing potential regenerative medicine therapies.