Influence of carbon nanotubes reinforcement on the structural feature and bioactivity of SiO2-Al2O3-MgO-K2CO3-CaO-MgF2 bioglass

Various glass compositions were synthesized using a melt-quenching technique doped with different concentrations of carbon nanotubes (CNTs) from 0.1 to 0.7% in the glassy system SiO2-Al2O3-MgO-K2CO3-CaO-MgF2. Density was determined by employing a liquid displacement method. Several physical parameters such as molar volume (V-m), oxygen molar volume (V-o) were calculated and found to be decreases from 36.49 +/- 0.729 to 24.28 +/- 0.485 x 10(-6) m(3)/mol, and 21.86 +/- 0.437 to 14.60 +/- 0.292 x 10(-6) m(3)/mol, respectively. However, density and oxygen packing density (OPD) increases from 1.99 +/- 0.099 to 2.98 +/- 0.149 x10(3) kg/m(3) and 45.74 +/- 0.914 to 68.49 +/- 1.369 x10(-3) kg-atom/l with increasing content of CNT. In the present study, reinforcement effects of CNTs were explained using several spectroscopic techniques like Fourier transform infrared, ultraviolet-visible (UV-Vis), Raman, and nuclear magnetic resonance (NMR) spectroscopy, respectively. Based on Tauc plots of the UV-Vis spectra, the energy band gap was determined and their values decreased from 6.95 to 6.23 x 10(-19) J which is owing to the formation of non-bridging oxygen (NBO) in the glassy matrix. Contact angle measurements were also performed to check the wettability of the glasses and their values increased with CNT % from 18.14 degrees to 77.8 degrees. Si-29-MAS-NMR spectroscopic study revealed the random distribution of two different cations, Ca2+ and Mg2+ within the glasses which lead to structural and topological frustration. To check the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and alkaline phosphatase assay were also performed. Owing to outstanding stability in various fluids like saline water, distilled water, and hydrochloric acid, the fabricated glasses exhibited functional activities with an adequate proliferation of rat calverail osteoblast cells. Consequently, based on the various characterization techniques such as mechanical, tribological, and biological activities, the fabricated bioactive glasses can be used for biomedical and multifunctional applications.

Automated summary

The study investigated the synthesis of glass compositions doped with carbon nanotubes (CNTs) and their effects on physical parameters, structure, and biological activities. The results showed changes in density, physical parameters, and structural properties with increasing CNT content. Various spectroscopic techniques were used to explain the reinforcement effects of CNTs, and the glasses exhibited good wettability and bioactivity.