Photopatterned Hybrid Supramolecular/Polymer Hydrogels for Controlled Heparin Release and Stem Cell Growth

This paper reports hybrid gels combining a low-molecular-weight gelator (LMWG) and a photoinitiated crosslinked polymer gel (PG). The presence of the PG enhanced the stiffness and strength of the gel. The gels were loaded with heparin, and in the hybrid gel, the interpenetrated LMWG and PG networks somewhat restricted its release. In terms of stem cell growth, the hybrid gel significantly improved the performance of the PG because of the presence of the LMWG, which is an excellent substrate for stem cells in its own right. Furthermore, the presence of heparin in the hybrid gels also enhanced stem cell proliferation over longer timescales. Finally, these gels were photopatterned within the well-plates used for tissue culture, with patterning helping control stem cell proliferation. In summary, these hybrid gels combine the advantageous features of both LMWG and PG: rheological performance is endowed by the PG with stem cell compatibility provided by the LMWG. The hybrid gels also control the release of the bioactive agent heparin and have capacity to be shaped and patterned. Patterned gels such as these, capable of directing stem cell growth, have potential in regenerative medicine.