Wound Healing and Bone Regeneration

The regenerative capacity of bone is robust and effective at addressing wounds under normal conditions. A proportion of fractures, however, present conditions that are not conducive to regeneration and place the fracture at high risk for nonunion or delayed union. For example, fractures located at sites of marginal vascularity and those associated with a large area of bone loss repair with difficulty if at all. As a result, a great deal of effort has been invested in the development of treatment methods for fractures and defects at risk of nonunion, as they would not likely heal 

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Heteroatom biodegradable and electrically conducting polymers, (IV), effective for tissue engineering applications were prepared by Schmidt [4] and used in spinal cord regeneration, wound healing, and bone repair. 

Properly engineered silk scaffolds have been successfully apphed in wound healing and in tissue engineering/regeneration of bone, cartilage, tendon, and ligament tissues as shown in Table 14.2 [24]. 

Although red blood cells (erythrocytes) play only a minimal role in wound healing and blood-biomaterial interactions, the contact of red blood cells with the material can lead to hemolysis. Hemolysis is the breakage of the erythrocyte s membrane with the release of intracellular hemoglobin. Normally, red blood cells live for 110-120 days. After that, they naturally break down and are removed from the circulation by the spleen. Some diseases and medical devices cause red blood cells to break too soon requiring the bone marrow to accelerate the regeneration of red blood cells (erythropoesis). Medical devices for hemodialysis, heart-lung-bypass machines or mechanical heart valves induce more hemolysis than smaller implants like stents or catheters [201]. 

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