Gurbinder Kaur

A review of bioactive glasses: Their structure, properties, fabrication and apatite formation

Bioactive glass and glass-ceramics are used in bone repair applications and are being developed for tissue engineering applications. Bioactive glasses/Bioglass are very attractive materials for producing scaffolds devoted to bone regeneration due to their versatile properties, which can be properly designed depending on their composition. An important feature of bioactive glasses, which enables them to work for applications in bone tissue engineering, is their ability to enhance revascularization, osteoblast adhesion, enzyme activity and differentiation of mesenchymal stem cells as well as osteoprogenitor cells. An extensive amount of research work has been carried out to develop silicate, borate/borosilicate bioactive glasses and phosphate glasses. Along with this, some metallic glasses have also been investigated for biomedical and technological applications in tissue engineering. Many trace elements have also been incorporated in the glass network to obtain the desired properties, which have beneficial effects on bone remodeling and/or associated angiogenesis. The motivation of this review is to provide an overview of the general requirements, composition, structure-property relationship with hydroxyapatite formation and future perspectives of bioglasses.Attention has also been given to developments of metallic glasses and doped bioglasses along with the techniques used for their fabrication.

Synthesis, cytotoxicity, and hydroxyapatite formation in 27-Tris-SBF for sol-gel based CaO-P2O5-SiO2-B2O3-ZnO bioactive glasses

CaO-P2O5-SiO2-B2O3-ZnO bioactive glasses were prepared via an optimized sol–gel method. The current investigation was focused on producing novel zinc based calcium phosphoborosilicate glasses and to evaluate their mechanical, rheological, and biocompatible properties. The morphology and composition of these glasses were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The particle size, mechanical and flexural strength was also determined. Furthermore, the zeta potential of all the glasses were determined to estimate their flocculation tendency. The thermal analysis and weight loss measurements were carried out using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) respectively. For assessing the in-vitro bioactive character of synthesized glasses, the ability for apatite formation on their surface upon their immersion in simulated body fluid (SBF) was checked using SEM and pH measurements. MTS assay cytotoxicity assay and live-dead cell viability test were conducted on J774A.1 cells murine macrophage cells for different glass concentrations.

Review and the state of the art: Sol–gel and melt quenched bioactive glasses for tissue engineering

Biomaterial development is currently the most active research area in the field of biomedical engineering. The bioglasses possess immense potential for being the ideal biomaterials due to their high adaptiveness to the biological environment as well as tunable properties. Bioglasses like 45S5 has shown great clinical success over the past 10 years. The bioglasses like 45S5 were prepared using melt-quenching techniques but recently porous bioactive glasses have been derived through sol-gel process. The synthesis route exhibits marked effect on the specific surface area, as well as degradability of the material. This article is an attempt to provide state of the art of the sol-gel and melt quenched bioactive bioglasses for tissue regeneration. Fabrication routes for bioglasses suitable for bone tissue engineering are highlighted and the effect of these fabrication techniques on the porosity, pore-volume, mechanical properties, cytocompatibilty and especially apatite layer formation on the surface of bioglasses is analyzed in detail. Drug delivery capability of bioglasses is addressed shortly along with the bioactivity of mesoporous glasses.

Combined and individual doxorubicin/vancomycin drug loading, release kinetics and apatite formation for the CaO–CuO–P2O5–SiO2–B2O3 mesoporous glasses

The novel mesoporous glass series based on (25 − x)CaO–xCuO–10P2O5–5B2O3–60SiO2 (x = 2.5, 5, 7.5, 10) has been prepared using the sol–gel technique. The pore size of the prepared mesoporous bioactive glasses (MBG) lies between 6.1 and 9.1 nm, whereas the surface area varies from 281 to 418 m2 g−1. The pH variation, zeta potential, Fourier transform infra-red (FTIR) spectroscopy and simulated body fluid (SBF) studies indicated the in vitro bioactivity of all the MBGs. The MBGs were loaded with the anticancerous and antibacterial drugs, doxorubicin and vancomycin, respectively. The increasing copper content predominantly influenced the bioactive properties as well as the drug loading and release kinetics of the doxorubicin and vancomycin drugs. In addition to the individual loading of drugs in the MBG, both the drugs were also loaded together in the MBG to investigate the effect of combined loading on the release capability of the MBGs.

Antibacterial and anticancerous drug loading kinetics for (10-x)CuO-xZnO-20CaO-60SiO2-10P2O5 (2 ≤ x ≤ 8) mesoporous bioactive glasses

In the present study, antibacterial and anticancerous drug loading kinetics for the (10-x)CuO-xZnO-20CaO-60SiO2-10P2O5 (2≤x≤8, varying in steps of 2) mesoporous bioactive glasses (MBGs) have been studied. XRD analysis of the as prepared glass samples proved its amorphous nature. Scanning electron microscopy (SEM) revealed the apatite layer formation on the surface of the MBGs after soaking for 15 days in SBF. Ion dissolution studies of calcium, phosphorous and silicon have been performed using inductively coupled plasma (ICP). FTIR and Raman analysis depicted about the presence of various bonds and groups present in the glasses. The pore size of MBGs lies in the range of 4.2–9.7 nm. Apart from this, specific surface area of the MBGs varied from 263 to 402 cm2/g. The MBGs were loaded with Doxorubicin (DOX), Vancomycin (VANCO) and Tetracycline (TETRA) drugs among which, the decreasing copper content influenced the loading properties of doxorubicin and tetracycline drugs. Vancomycin was fully loaded almost in all the MBGs, whereas other drugs depicted varying loading with respect to the copper content.Graphical Abstract

Biomaterials Influencing Human Lives

Biomaterial development has influenced human lives to a large extent by its versatile medical applications and very promising future. The field of biomaterials has been experiencing steady and strong growth as large number of pharmaceutical firms and manufacturer companies are investing in the production and development of new commercialized biomaterial products.

An Introduction and History of the Bioactive Glasses

When the hierarchy turns towards higher level, the molecular events become more complex and convoluted. The human embryo development is quite complex as it originates from a 32-celled stage and metamorphoses by a series of metabolic and physical processes. The process of fetus formation is full of breathtaking complexity as it involves the development of lungs, heart, gut, nerves, limbs, bones, blood vessels, cartilages, circulatory system, nervous system and excretory system. The constant wear and tear of muscles, joints and other vital body tissues takes place during the lifetime of human body. Due to the advancement of medical science, artificial limbs and transplantation have helped the human body to resume the day-to-day chores, but the biomaterials have revolutionized the world due to their capability to repair the damaged tissues by self-healing mechanism. These days, the bioactive materials have become an imperative and indispensable tool for the medical science due to their numerous advantages. Hence, the current focus is given on the history, categories and requirements of the biomaterials especially bioactive glasses (please consult the Editor’s note in order to clarify the usage of the terms bioglass, bioactive glass and biocompatible glasses).

Mechanical, dielectric and optical assessment of glass composites prepared using milling technique

In the present investigation, mechanical and spectroscopic properties of glass composites have been investigated. The glass composites have been prepared by the milling technique instead of using any filler particle. Due to the presence of different alkaline earth modifiers in composites, marked difference in their strength and optical properties is observed. The band gap, Urbach energy and the extinction coefficient of the glass composites have been calculated using UV–visible spectroscopy. Moreover, the real and imaginary dielectric constants have also been calculated for all the composites in addition to the Weibull statistics and cumulative probability of failure. The results have been discussed in light of comparison between the glass composites and the individual glasses. The mechanical and optical properties indicate marked effect on the mechanical strength, band gap and Urbach energy for glass composites as compared with the individual glasses.

Biodegradable Metals as Bioactive Materials

In 1895, Lane first introduced metal plates for bone implants. Due to the corrosion-related problems of metals, 18–8 stainless steels were introduced in the 1920s, which attracted the attention of many clinical researchers due to its corrosion-resistant properties. Since 2000, the research interest is more inclined toward the synthesis and applications of biodegradable metals.

Effect of strontium substitution on the cytocompatibility and 3-D scaffold structure for the xSrO–(10−x) MgO–60SiO2–20CaO–10 P2O5 (2 ≤ x ≤ 8) sol–gel glasses

In the present study, novel glasses xSrO–(10−x) MgO–60SiO2–20CaO–10 P2O5 (2 ≤ x ≤ 8, in steps of 2) are synthesized via sol–gel method. The current work focusses on the evaluation of mechanical, physical and biocompatible properties for sol–gel glasses. The pore size and surface area of these glasses were studied using BET analysis. The structural aspect of the glasses/glass ceramics was studied by XRD and Raman spectroscopy. The cytotoxicity assays were conducted for MG63 human osteosarcoma cell line. Furthermore, the as prepared glasses were used for the fabrication of 3-D porous scaffolds via polymer replication method. The loaded green bodies have been sintered at 700, 800 and 900 °C and were kept for 6 h to densify the glass network. The effect of sintering temperature on the structure and properties of as prepared scaffolds were analyzed via scanning electron microscopy (SEM) and porosity calculations.Graphical Abstract