Hall for all the time and effort he put into helping me understand the various concepts of research design and implementation. I am very grateful for all the sacrifices my parents have endured to ensure my success in life. Biomaterials are materials that have a reaction to the body or cause a reaction within the body.
Bioactive materials are those that bind to bone, have the ability to direct the restoration of natural bone tissue and are resorbed.1 The third and current generation are instructive materials. Disease, injury, and trauma are the main factors leading to degeneration of skeletal tissue.3 When the body's natural regenerative abilities cease to repair tissue damage, tissue degeneration initiates a cascade of physiological impairments; if left untreated, they will cause necrosis at the site of injury, impaired function of the affected area, and/or reduced quality of life. Although autograft is the most favorable method of transplantation and has the lowest risk of stimulating the immune response, autograft has several limitations; they are painful for the patient, expensive, pose a risk of donor-site morbidity, and the areas of the body from which the graft can be taken are severely limited in terms of the amount of bone required for the graft.5 Grafts should be taken from areas of the body that have a large enough area to ensure the mechanical and structural stability of the donor site, usually the posterior iliac crest.4 Donor site morbidity is defined by any major or minor complication resulting from the removal of tissue from the patient; examples of such complications can be seen in Table 1.5 The main consequences are those requiring additional surgery, additional time for hospital admission,.
7 Since allografts are obtained from a different individual, the proteins present on the cell surfaces of the donor tissue will differ slightly from those present within the patient's cells. During the final stage of repair, the hard callus, made of woven spongy bone, is replaced by dense cortical bone.10 While the body is able to repair minimal damage; therapeutic intervention is often needed for extensive trauma to ensure the success and speed of repair.11. Tissue engineering combines medicine and materials science to promote the regeneration of a patient's tissues through the use of scaffolds, cells, and biologically active molecules.15 Tissue scaffolds, often seeded with cells or various growth factors, are used to mediate repair. of skeletal tissue by interacting with surrounding tissue and promoting the formation of healthy tissue. 6 Properties of a good scaffold material include: controllable biodegradability, osteoconductivity, and the ability to disperse cells. 12 Biodegradability is the ability of a material to is chemically dissolved through biological means and is an important property of a scaffold material because a high degree of biodegradability ensures that the scaffold will eventually be replaced by the host tissue, which is the main goal of tissue engineering.11 While the ability to is degraded within the body is important, the rate of this degradation is also of equal interest; if.
If the rate of degradation is too slow, the prolonged presence of a foreign material inside the body can cause an unwanted immunological response.3 Osteoconductivity is the ability of a material to facilitate the attachment and proliferation of bone-forming cells.
BIOACTIVE GLASS
Compounds or minerals can be added to existing glass compositions to increase the biocompatibility of a glass. Chemical or mineral additions and changes to the original composition of Bioglass have produced new compositions of glasses, 45S5 and 58S. 45S5 glasses are very similar to the original composition of Bioglass; they consist of silica, sodium oxide, calcium oxide, phosphorus pentoxide, and depending on the type of 45S5 glass, calcium fluoride and boron oxide.
Ions released by these glass compositions have been shown to cause gene regulation of bone-forming cells.15. This composition differs in that it has significantly more quartz and calcium oxide, no sodium oxide and less phosphorus pentoxide. The silica-rich gel layer on the surface of the glass facilitates a strong bond between the glass and the bone.16 Silicon has also been proven to increase the activity of osteoblasts, the cells responsible for the synthesis of new bone, which then accelerates the formation of new bone tissue.17.
The interaction of bioactive glasses and an aqueous environment such as the body has been described as a five-step process. Soluble silica, Si(OH)4, is released into solution leaving silanols on the surface of the glass. The primary techniques for bioactive glass manufacturing are a melt-derived process or a sol-gel method.
Fused glass is made by combining the glass powder and oxide components and fusing them together in a crucible at high temperatures; the exact temperature depends on the glass composition. Sol-gel is a process characterized by the transition of a glass system from a liquid "sol" to a solid "gel" phase and involves the chemical synthesis of inorganic materials. 13 Sol-Gel glasses are synthesized via a hydrolytic reaction of an alkoxide precursor that forms a colloidal silica solution. 20 Tetraethyl orthosilicate is added as a silica precursor, triethyl phosphate is used to introduce phosphate, and a calcium nitrate salt adds calcium.
A polycondensation reaction occurs involving the silica in the solution, creating a silica network, which in turn creates the network. This heating not only removes unwanted by-products, but also stimulates the polycondensation reactions in the gel.20.
BONE MORPHOGENETIC PROTEINS
ELISA
BET analysis was performed to observe a hypothesized change in porosity and surface area at varying temperatures and to determine an effective heating temperature for the consolidation step. The efficiency of the heating temperature is defined as the temperature that maintains the intrinsic pore size of the scaffold. As the gel consolidates, the organics in the gel network are burned off, resulting in shrinkage of the gel.
These pores within the nanostructure also act as an ingrowth area into the tissue, which further increases the bioactivity of the glasses.27 The surface area of the first batch of glass consolidated at 625 °C was found to be 213.5734 m²/g with an average pore volume of 0.444 cm3/g and an average pore size of 66.06 Å. A second set of experiments was conducted to investigate the effect of curing temperature on glass porosity and surface area. The shape of the isotherm graph for the second batch of glass at the second temperature remained the same.
The average pore size for each of the heated glasses was found to be on the order of 7 nm. The results of the BET analysis showed that as the temperature increased, the surface area and pore volume decreased. This means that the glasses consolidated at lower temperatures have a small pore size, but a very large surface area and pore volume.
To determine the ideal heating temperature for the consolidation step, a balance between surface area, pore size and pore volume must be maintained. The phase identified for the first group of glass using ICDD is indicated by the stick pattern and has been determined to be calcium oxide. As the temperature increases, the intensity of the silicon oxide peaks increases to a maximum at 675°C.
The presence of calcium oxide is probably due to calcium remaining dissolved in the pore fluid of the gel. It is unclear whether this observed release is the release of protein adsorbed to the surface of the glass or whether it is true release from protein filled into the pores. Future studies need to be performed to properly quantify BMP-2 release and to assess the validity of the data.
The prepared glass is affected by the final heat treatment temperature; the surface area and pore volume decrease as the temperature increases. To develop a greater understanding of the effect of the final heating temperature on this composition of sol-gel-derived glass and to narrow down the ideal temperature for glass consolidation, further heating studies need to be performed.
