Production and characterisation of novel injectable chitosan/methylcellulose/salt blend hydrogels with potential application as tissue engineering scaffolds

The properties of an injectable chitosan (CS)/methylcellulose (MC) blend hydrogel used as a three-dimensional synthetic matrix for tissue engineering were investigated. CS/MC hydrogels were prepared via blending of CS, MC and salts under mild conditions without organic solvent, high temperature or harsh pH. Such blends were liquid at low temperature (∼4 °C), but gel under physiological conditions (37 °C). The effect of different salts including NaCl, Na3PO4, NaHCO3 and glycerophosphate (GP) on the CS/MC gelation process was investigated by rheological analysis from which possible gelation mechanisms were inferred. Viscoelastic characteristics indicated that CS/MC gels formed using different salts had different gelation temperature, gelation rate, and gel strength. Gelation temperature followed the order NaCl > GP > Na3PO4 > NaHCO3, gelation rate followed the order GP > NaHCO3 > Na3PO4, and gel strength followed the order GP > NaHCO3 > Na3PO4 (at 37 °C).CS/MC hydrogels were also characterised by infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). CS/MS gels formed with different salts had different gel structures, ranging from nonporous to microporous. When used as a scaffold for chondrocytes, CS/MC/Na3PO4 hydrogel resulted in good cell viability and proliferation.