Bioactive hydrogel-nanosilica hybrid materials: a potential injectable scaffold for bone tissue engineering

Abstract

Novel bioactive organic-inorganic hybrid materials that can serve as injectable hydrogel systems for bone tissue regeneration were obtained. The silica nanoparticles (SiNP) prepared in situ by the Stöber method were dispersed in collagen, collagen-chitosan or chitosan sols, which were then subsequently crosslinked. Laser scanning confocal microscopy studies, in which fluorescent SiNP were applied, and SEM images indicated that the nanosilica particles were distributed in the whole volume of the hydrogel matrix. In vitro studies on fibroblast cell viability indicated that the hybrid materials are biocompatible. The silica nanoparticles dispersed in the biopolymer matrix had a positive effect on cell viability. Studies on the mineralization process under simulated body fluid (SBF) conditions confirmed the bioactivity of prepared materials. SEM images revealed mineral phase formation in the majority of the hybrid materials developed. EDS analysis indicated that these mineral phases are mainly composed of calcium and phosphorus. The XRD studies confirmed that mineral phases formed during SBF incubation of hybrid materials based on collagen are bone-like apatite minerals. The silica nanoparticles added to the hydrogel at the stage of synthesis induced the occurrence of mineralization. This process occurs not only at the surface of the material but in its entire volume, which is important for the preparation of scaffolds for bone tissue engineering. The ability of these materials to undergo in situ gelation under physiological temperature and their bioactivity as well as biocompatibility make them interesting candidates for bioactive injectable systems.

Injectable hydrogels for cartilage and bone tissue engineering

“…Other inorganic materials such as nanosilica and Bioglass have been studied for the preparation of hybrid hydrogel systems. 288,289 For example, Vishnu Priya et al 290 have developed an injectable hydrogel system by using chitin and poly(butylene succinate) loaded with fibrin nanoparticles and magnesium-doped Bioglass. This hydrogel system enhances the initiation of differentiation and expression of alkaline phosphatase and osteocalcin, thus indicating its promise for regenerating irregular bone defects.…”

Chitosan‐based hydrogels: recent design concepts to tailor properties and functions

“…This is an alternative strategy to highly crosslinked hydrogels which are generally stiff materials with limited extensibility, poor swelling capability as well as slow molecular diffusion . Therefore, with the aim of designing CS hydrogels with excellent mechanical strength and high elasticity for tissue engineering and drug delivery applications, a large variety of inorganic NPs have been incorporated into hydrogels, such as silica NPs, metal NPs, hydroxyapatite (HAp) NPs, graphene oxide (GO) NPs and clay NPs . Han and Yan exploited the multifunctional groups of GO NPs to prepare supramolecular hydrogels of CS .…”

Natural marine sponges for bone tissue engineering: The state of art and future perspectives

“…The biosilica spicules are embedded into an organic matrix and it has been demonstrated that they are nontoxic for mammalian cells, already suggesting their biocompatibility . Indeed, biosilica derived from marine sponges is being considered for biomedical approaches, bone replacement and regeneration strategies in TE, specially because silica ions are known as an important element to stimulate bone formation . Bioactive silica glasses, for instance, bond and integrate to bone tissue through the formation of a silica gel layer, which attracts and stimulate osteoprogenitor cells to proliferate and to differentiate in osteoblasts, starting the synthesis and the deposition of bone organic matrix and matrix mineralization …”

“…42 Indeed, biosilica derived from marine sponges is being considered for biomedical approaches, bone replacement and regeneration strategies in TE, 33 specially because silica ions are known as an important element to stimulate bone formation. [44][45][46] Bioactive silica glasses, for instance, bond and integrate to bone tissue through the formation of a silica gel layer, which attracts and stimulate osteoprogenitor cells to proliferate and to differentiate in osteoblasts, starting the synthesis and the deposition of bone organic matrix and matrix mineralization. 12,14 In this context, some authors have performed in vitro studies to verify the biocompatibility of biosilica derived from marine sponges.…”