Responsive calcium (Ca²⁺) alginate-chitosan based hydrogel: A promising biomaterial for spinal cord injury

Spinal cord injury is damage to the spinal cord which causes lesions in the spinal cord and leads to an increase in extracellular Ca2+. It results in additional neuronal loss which causes temporary/permanent disability or even death. The aim of this study was to determine characteristics and the best composition of alginate – chitosan hydrogel responsive to Calcium (Ca2+) for spinal cord injury. Hydrogel synthesis with its compositions, namely chitosan was dissolved in 0.4% acetic acid, neutralized in pH 7 with 0.5 M NaOH, added some 0.85% NaCl in it, and added 5 alginate variations which were dissolved in 0.85% NaCl, next will centrifugation method. Based on the FTIR test, hydrogel showed stretching vibrations of Chitosan’s O–H bonds appeared in 3415.93cm-1 wavenumber, while Na groups of alginate isomer appeared in 1413.82 cm-1 wavenumber. The results of the cytotoxicity test using the MTT Assay method showed live cell percentage from less than 50% to 52.61% in Sample B and 83.83% in Sample C. The results of the injectability test showed that all samples were injectable with the highest percentage of injectability at 98.283%. The results of the UV-Vis spectrophotometric test showed that all hydrogel samples were able to absorb Ca2+. Hydrogels can be degraded at more than 90% within 14 days. The results of the morphology test (SEM) obtained 84.7-99.6 μm pore sizes.