Characterization of SiO2-Na2O-Fe2O3-CaO-P2O5-B2O3 glass ceramics

Bioactive glasses and glass-ceramics for hyperthermia treatment of cancer: state-of-art, challenges, and future perspectives

Bioactive glasses and glass-ceramics are well-proven potential biomaterials for bone-tissue engineering applications because of their compositional flexibility. Many research groups have been focused to explore the utility of bioactive glass-ceramics beyond bone engineering to hyperthermia treatment of cancer. Hyperthermia refers to raising the temperature of tumor close to 44°C at which malignant cells perish with negligible harm to normal cells. Hyperthermia can be employed by many means such as by ultrasonic waves, electromagnetic waves, infrared radiations, alternating magnetic fields, etc. Magnetic bioactive glass-ceramics are advantageous over other potential candidates for thermoseeds such as nanofluids, superparamagnetic nanoparticles because they can bond not only to the natural bone but also with soft tissues in few cases, which helps regenerating the affected part due to its bioactive nature. Strict restrictions on clinical settings ( H × f < 5 × 10 9 ) force the research activities to be more focused on material characteristics to raise the implant temperature to required ranges. Lots of efforts have been made in past years to tackle these challenges and design best-suited glass-ceramics for hyperthermia treatment. This review aims to provide essential information on the concept of hyperthermia treatment of cancer and recent developments in the field of bioactive glass-ceramics for cancer treatment. The advantages and disadvantages of magnetic glass-ceramics over other potential thermoseed materials are highlighted. In this field, the major challenges are to develop magnetic glasses, which have fast and bulk crystallization with optimized magnetic phases with lower Curie and Neel temperatures.

Review on titanium and titanium based alloys as biomaterials for orthopaedic applications

Variety of implant materials have been employed in various disciplines of medical science depending on the requirement of a particular application. Metals, alloys, ceramics, and polymers are the commonly used biomaterials. The main focus of this study is to review the various structural and microstructural properties of titanium and titanium based alloys used as orthopaedic implants. Orthopaedic implants need to possess certain important qualities to ensure their safe and effective use. These properties like the biocompatibility, relevant mechanical properties, high corrosion and wear resistance and osseointegration are summarized in this review. Various attempts to improve upon these properties like different processing routes, surface modifications have also been inculcated in the paper to provide an insight into the extent of research and effort that has been put into developing a highly superior titanium orthopaedic implant.

Effect of composition on the release kinetics of phosphate controlled release glasses in aqueous medium

Phosphate controlled release glass (CRG) specimens with varying composition were prepared and their dissolution rates were measured by weight-loss method in leach tests conducted in 30? deionized water. Results show that the release rate of phosphate CRG is highly dependent on its composition. Based on the composition of binary 40Na(2)O-60P(2)O(5) glass, the dissolution rate of phosphate CRGs can be reduced by substitution of divalent metal oxides such as CaO for Na(2)O or trivalent metal oxides such as Al(2)O(3) for P(2)O(5), but increased by introducing B(2)O(3) or SiO(2) into the glass composition. FTIR spectra analysis showed that the composition adjustment caused structural change of the phosphate CRG, which typically demonstrates strengthened M em leader O bond formed by the non-bridging oxygen with the metal ions introduced on the [PO(4)] tetrahedron and the P?O?P bond formed by the bridging oxygen between two [PO(4)] tetrahedrons if its chemical durability is improved.

Dissolution mechanism and release kinetics of phosphate controlled release glasses in aqueous medium

Leach test of a phosphate controlled release glass (CRG) were conducted in aqueous medium under different conditions. Results show that the phosphate CRG dissolves congruently in deionized water. Its dissolution rate is dependent with the solution pH, temperature and concentrations of phosphate ions and calcium ions in the medium, but independent with the stirring speed of the solution. Analysis leads to a conclusion that the dissolution of phosphate glass is a reaction-controlled process. Discussions on the dissolution mechanisms show that the nature of the reaction in the hydrated layer is the dissociation of Na(+) ions from the phosphate chains under the attack of the penetrating water molecules. The velocity of formation and development of hydrated layer depends on the diffusion rate of water molecules inside glass. The dissolution is realized by the breakage of P-O-P bonds in the phosphate network within the hydrated layer. The chelating ability of polyphosphate with divalent cations play an important role in the dissolution process of phosphate CRGs and was found responsible for the accelerated or decelerated dissolution of the CRG in sodium hexametaphosphate (SHMP) or CaCl(2) solutions, respectively.