New sol‐gel bioactive glass and titania composites with enhanced physico‐chemical and biological properties

Abstract

We developed TiO2 matrix composites modified by sol-gel bioactive glasses (SBG) of either high CaO content (A2) or high SiO2 content (S2). The latter were mixed with titanium dioxide (TiO2) at 75:25, 50:50, and 25:75 weight ratios and sintered at 1250°C for 2 h. We examined the effects of various types (A2 or S2) and compositional TiO2 :SBG ratios on the mechanical properties of resulting composites, their bioactivity and human bone marrow mesenchymal stem cells (MSC) response. The chemistry of SBGs influenced the phase composition, mechanical and biological properties of the composites. Rutile and titanite prevailed in A2-TiO2 composites, and rutile and crystobalite in S2-TiO2 composites. Compressive strength increased significantly for 25A2-TiO2 composites (140 MPa) compared to matrix TiO2 (58 MPa). Composites containing 50-75 wt % of either SBG displayed bioactive properties as determined by simulated body fluid test. Compared to TiO2, human bone marrow stromal cell (BMSC) viability was enhanced on the composites containing 25 wt % of either SBG, whereas the composites modified by 25 wt % of S2 enhanced alkaline phosphatase activity and mineralization in cultures treated with osteogenic inducers-dexamethasone (Dex) or bone morphogenetic protein. Increasing amounts of A2 in TiO2 matrix decreased cell viability but increased collagen deposition and mineralized matrix production by BMSC. Considering the physico-chemical and biological properties of the presented composites, the modification of TiO2 with SBG may prove useful strategy in several bone tissue related regeneration strategies.

Bioactive sol‐gel glasses: Processing, properties, and applications

“…It was also shown that glass composition plays a key role in affecting the biological properties of HA‐, polymer (PLGA, PCL)‐ and TiO 2 ‐based composites, in which sol‐gel bioactive glass have been incorporated. The research group led by Cholewa‐Kowalska extensively investigated the effect of different amounts of SiO 2 in the glass on the biological properties of the composites and found that, except for HA‐based materials, where cell viability and ALP cellular activity were improved with respect to pure HA regardless of silica content, lower SiO 2 amounts induced, in all other cases, an enhanced differentiation of bone marrow precursor cells into an osteoclastic phenotype and a reduction in osteoblast‐like cell metabolism. Moreover, it was demonstrated that a meaningful relationship between ALP activity, glass chemical composition and processing of scaffolds exists…”

Chitosan-based scaffolds for bone tissue engineering

“…Other ceramics utilized for bone tissue engineering include bioactive glasses, glass-ceramics, silica and titania. [8][9][10][11][12] Both synthetic and natural polymers have been investigated as bone scaffold materials. Synthetic polymers of interest include polyesters such as polycaprolactone (PCL), 13,14 poly(lactic acid) (PLA), poly(glycolic acid) (PGA) and poly(latic-co-glycolic acid) (PLGA).…”

A highly bioactive and biodegradable poly(glycerol sebacate)–silica glass hybrid elastomer with tailored mechanical properties for bone tissue regeneration

“…[17][18][19][20][21] Compared to the conventional melting method, sol-gel derived SBG presented a uniform chemical structure and high bioactivity in vitro and in vivo. [22][23][24][25][26] To optimize the properties for bone regeneration, using bioactive agents, sol-gel derived SBG microscale and nanoscale particles have been utilized to prepare polymer composites. [27][28][29] To further improve the chemical structure and tailor the properties of composites, a softened bioactive glass sol, with a molecular-level composition, has been previously reported to fabricate bioactive inorganic-polymer hybrid biomaterials.…”