Alginate / Gelatin / Nano-Silica Hydrogel Microcapsules for Bone Tissue Engineering Applications

Hydrogel microcapsules have diverse applications in bone tissue engineering due to their hydrophilic nature and desirable structure for cell growth which allows for excellent nutrient and oxygen transfer. In this study, 1 wt% alginate (alg)/ 1.25 wt% gelatin (gel)/ 1 wt% nano-silica (nSiO2) hydrogel microcapsules containing MG-63 cells with density of 2E6 cells per ml of gel were prepared in calcium chloride bath (0.1M) using electrostatic droplet generation method with voltage of 8 Kv. Alg/gel/nSiO2 hydrogels were characterized by mechanical strength, swelling and biodegradation analyses and were compared with control hydrogels (alg/gel). The presence of nano-silica in alg/gel hydrogels led to controlled swelling and biodegradability behavior. Moreover, mechanical strength in nano-silica containing hydrogels intensified. Proliferation and viability of encapsulated MG-63 cells were evaluated by trypan blue staining and MTT assay. alg/ gel/ nSiO2 microcapsules were biocompatible when tested to MG-63 cell line. At the end of 28 days, no dramatic discrepancy in the cell numbers of alg/ gel/ nSiO2 and alg/ gel microcapsules was detected and both types of microcapsules were biocompatible. However, alkaline phosphatase activity and alizarin red staining analyses demonstrated that introduction of nano-silica into conventional alg/gel hydrogel microcapsules can encourage better matrix mineralization and calcium deposition. Thus, these results prove that prepared alg/ gel/ nSiO2 hydrogel microcapsules can induce better bone generation and would be a forthcoming candidate for bone tissue engineering applications.

Keywords:

Bone Tissue Engineering , Hydrogel , Alginate , Gelatin , Nano-Silica