This work is aimed to develop a biocompatible, bactericidal and mechanically stable biomaterial to overcome the challenges associated with calcium phosphate bioceramics. The influence of chemical composition on synthesis temperature, bioactivity, antibacterial activity and mechanical stability of least explored calcium silicate bioceramics was studied. The current study also investigates the biomedical applications of rankinite (Ca3Si2O7) for the first time. Sol-gel combustion method was employed for their preparation using citric acid as a fuel. Differential thermal analysis indicated that the crystallization of larnite and rankinite occurred at 795 °C and 1000 °C respectively. The transformation of secondary phases into the desired product was confirmed by XRD and FT-IR. TEM micrographs showed the particle size of larnite in the range of 100-200 nm. The surface of the samples was entirely covered by the dominant apatite phase within one week of immersion. Moreover, the compressive strength of larnite and rankinite was found to be 143 MPa and 233 MPa even after 28 days of soaking in SBF. Both samples prevented the growth of clinical pathogens at a concentration of 2 mg/mL. Larnite and rankinite supported the adhesion, proliferation and osteogenic differentiation of hBMSCs. The variation in chemical composition was found to influence the properties of larnite and rankinite. The results observed in this work signify that these materials not only exhibit faster biomineralization ability, excellent cytocompatibility but also enhanced mechanical stability and antibacterial properties.
Bioactive silicates have gained popularity as bone graft substitutes in recent years due to their exceptional ability to bind to host tissues. The current study investigates the effect of changing the metal ion-to-fuel ratio on the properties and biological activity of monticellite prepared via the sol-gel connived combustion technique. Single-phasic monticellite was obtained at 900 °C, without any secondary-phase contaminants for the fuel-lean, stoichiometric, and fuel-rich conditions. SEM and TEM micrographs revealed the porous, spongy morphology of the materials. Because of the reduced crystallite size and higher surface area, the biomineralization of monticellite prepared under fuel-lean conditions resulted in more apatite deposition than those of the other two samples. The results show that the material has a good compressive strength comparable to natural bone, while its brittleness is equivalent to the lower moduli of bone. In terms of antibacterial and antifungal activities, the monticellite bioceramics outperformed the clinical pathogens. It can be used for bone tissue engineering and other biological applications due to its excellent anti-inflammatory and hemolysis inhibitory properties.