Question 1

What are the main types of degradation that resorbable biomaterials undergo in the body?

Accepted Answer

Resorbable biomaterials degrade through three primary mechanisms: oxidative, hydrolytic, and enzymatic degradation. Oxidative degradation occurs when the body releases oxidative species that attack polymer chains, causing chain scission. Hydrolytic degradation involves water attacking susceptible bonds in the polymer to generate oligomers and monomers. Enzymatic degradation is catalyzed by hydrolases, which can increase the rate of hydrolytic degradation by up to 10 times.

Question 2

How does pH affect the degradation rate of resorbable sutures?

Accepted Answer

pH significantly influences resorbable suture degradation rates. Polydioxanone degraded most rapidly in acidic solutions, retaining only 41% of original tensile strength after five weeks, compared to 49% in neutral and 78% in alkaline solutions. Polyglyconate sutures degraded similarly across all pH conditions, retaining approximately 42% of strength. The ester bonds in both materials are susceptible to hydrolytic scission, which is enhanced at high and low pH levels.

Question 3

What is the difference between hydrophilic and hydrophobic resorbable materials during degradation?

Accepted Answer

Hydrophilic resorbable materials absorb water rapidly and degrade uniformly throughout their structure. Hydrophobic materials absorb water more slowly and degrade from the outside inward, creating a degradation gradient. This difference in water absorption directly affects the degradation pattern and timeline of the material within the body, influencing how long the suture maintains its mechanical strength.

Question 4

How is tensile strength measured in resorbable biomaterials during degradation studies?

Accepted Answer

Tensile strength is determined by loading a sample until failure using a tensile tester. The peak force at failure is divided by the cross-sectional area of the suture to calculate tensile stress. Percent tensile strength retained is calculated by comparing the post-incubation stress to the initial control sample stress. This method enables researchers to track how mechanical properties change as materials degrade over time in different environments.

Question 5

Why are polyesters like polydioxanone commonly used as resorbable suture materials?

Accepted Answer

Polyesters like polydioxanone are widely used because their ester groups are easily degraded via hydrolysis. When implanted, the material absorbs water and hydrolytic scission begins wherever the material contacts water. This predictable degradation mechanism allows the suture to hold wounds together long enough for healing before the material breaks down, eliminating the need for surgical removal while maintaining controlled strength loss.

Question 6

What are the main applications of resorbable biomaterials in biomedical engineering?

Accepted Answer

Resorbable materials are used in surgical procedures as sutures that eliminate the need for removal after healing. In tissue engineering, they serve as scaffolds providing three-dimensional structure for engineered tissue, degrading gradually as cells create their own structural material. Resorbable materials also support bone grafting procedures, where they degrade as native bone grows, offering an alternative to donor bone while maintaining structural support during healing.

Question 7

How do natural and synthetic resorbable sutures differ in composition and use?

Accepted Answer

Natural resorbable sutures include materials like silk and catgut, historically used for thousands of years. Synthetic resorbable sutures are created from materials such as polyglycolic acid, polydioxanone, and polycaprolactone, offering more predictable degradation rates. Both types are typically used for internal procedures like general surgery, where the suture must maintain strength during healing and then safely degrade without requiring removal. Understanding how these materials function supports broader biomedical imaging and analysis techniques used to visualize tissue healing and material integration.

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