Thixotropic injectable hydrogel using a polyampholyte and nanosilicate prepared directly after cryopreservation.
Success of tissue engineering applications in regenerative medicine requires the preservation of tissue-engineered products at a low temperature. This can be successfully achieved by the use of cryoprotective agent (CPA). In this study, we formulated a unique injectable hydrogel for the purpose of cell delivery after cryopreservation by using polyampholyte CPA. The polyampholyte showed excellent post-thaw cell survival, and after thawing, the polymeric CPA did not have to be removed because of its low cytotoxicity. The polyampholyte could be transformed into a hydrogel by mixing with nanosilicates. Previously, nanosilicates were used to improve mechanical properties, but this is the first report of the use of a nanosilicate together with CPA to formulate hydrogels. Inclusion of the nanosilicate led to the formation of thixotropic hydrogels, which can be injected using fine needles. These gels with tunable mechanical properties can be injected into defect sites to form scaffolds for cell growth and tissue repair, and they do not require any separate seeding of cells before injection, thus eliminating the need for cell harvesting and cell maintenance. This is a distinct system in which cells can be cryopreserved until before usage; when required, the cells in the polyampholyte can be revived to their original state and the thixotropic hydrogel can be formed. The combination of thixotropy and cytocompatibility of the gels could enable a wide range of biomedical applications such as cell delivery and orthopedic repair.
School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
Minkle
M
Jain
School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan. Electronic address: mkazuaki@jaist.ac.jp.
Kazuaki
K
Matsumura
D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods*; D055119:Elastic Modulus; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007267:Injections; D051379:Mice; D053761:Nanocomposites / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D011107:Polylysine / Q000737:chemistry; D017640:Silicates / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013386:Succinates / Q000737:chemistry; D014961:X-Ray Diffraction
D017640:Silicates; D013386:Succinates; D011107:Polylysine; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
Cryopreservation; Injectable hydrogel; Nanocomposite; Polyampholyte; Thixotropy