Interpenetrated Si-HPMC/alginate hydrogels as a potential scaffold for human tissue regeneration

Interpenetrated gels of biocompatible polysaccharides alginate and silanized hydroxypropyl methyl cellulose (Si-HPMC) have been studied in order to assess their potential as scaffolds for the regeneration of human tissues. Si-HPMC networks were formed by reduction of the pH to neutral and alginate networks were formed by progressive in situ release of Ca(2+). Linear and non-linear mechanical properties of the mixed gels at different polymer and calcium concentrations were compared with those of the corresponding single gels. The alginate/Si-HPMC gels were found to be stiffer than pure Si-HPMC gels, but weaker and more deformable than pure alginate gels. No significant difference was found for the maximum stress at rupture measured during compression for all these gels. The degrees of swelling or contraction in excess water at pH 7 as well as the release of Ca(2+) was measured as a function of time. Pure alginate gels contracted by as much as 50 % and showed syneresis, which was much reduced or even eliminated for mixed gels. The important release of Ca(2+) upon ageing for pure alginate gels was much reduced for the mixed gels. Furthermore, results of cytocompatibility assays indicated that there was no cytotoxicity of Si-HPMC/alginate hydrogels in 2D and 3D culture of human SW1353 cells. The results show that using interpenetrated Si-HPMC/alginate gels has clear advantages over the use of single gels for application in tissue regeneration.