Textile Materials for Good Health and Wellbeing by Unknown

Author:Unknown
Language: eng
Format: epub
ISBN: 9789819764969
Publisher: Springer Nature Singapore

4.2 Biodegradable Polymers

Biodegradable polymer refers to solid polymeric devices and materials that undergo macromolecular degradation, leading to their dispersion in vivo. It is essential to note that this definition excludes degradation caused by environmental factors, fungi, or bacteria. Biodegradable polymeric systems or devices are susceptible to attack by biological elements.

As an outcome, the integrity of the system, as well as in some cases, the macromolecules themselves, can be affected, leading to the production of fragments or other degradation by-products. While all of these fragments have the potential to be removed from their original site of action, it is important to emphasize that they may not necessarily exit the body.

Bio-absorbable polymer materials dissolve in body fluids without experiencing polymer chain scission or molecular mass reduction. The gradual dissolution of water-soluble implants within the body fluids is an example. When dispersed macromolecules of bio-absorbable polymer are excreted, it is called a bio-resorbable polymer [35]. For various biomedical applications, biodegradable polymeric materials that include both synthetic and biologically derived (natural) polymers have been extensively studied. Biodegradation is a process causing cleavage of bonds within the polymer, leading to polymer erosion [36]. Polymeric biomaterials are categorized as hydrolytically degradable and enzymatically degradable polymers based on their mode of degradation. Depending on the implantation site and enzyme availability, the natural polymers exhibit varying degradation rates in vivo. Altering the chemical composition of these polymers can greatly impact their rate of degradation. While natural polymers offer advantages such as bioactivity, presence of receptor binding to cells, susceptibility to cell-mediated proteolytic degradation, and natural remodeling, they also have disadvantages such as strong immunogenic response, purification complexities, and potential risks of disease transmission [37].

Chitin, the most abundant natural amino-polysaccharide, along with its derivative chitosan, is a remarkable natural polymer. Chitin is predominantly found in the exoskeleton of insects and various invertebrates. They possess extreme hydrophobicity and insolubility in water and most organic solvents. Chitosan, derived from chitin through chemical processing, is highly recommended for wound dressing due to its excellent properties, such as biodegradability, biocompatibility, non-toxicity, and adsorption capabilities [38]. Despite their potential for wound healing, materials containing chitosan face limitations due to their low mechanical strength under physiological conditions [39]. Collagen is an important biomaterial in medical applications due to its unique characteristics such as biodegradability and weak antigenicity [40]. Collagen, which makes up a quarter of the body's total protein, has a fibrous structure that provides strength and support to various tissues such as tendons, ligaments, and skin. These proteins are composed of polypeptide chains (α-chains) that form a unique triple helical structure, measuring 300 nm in length and 1.5 nm in diameter. There are more than twenty different types of collagen in animal tissues, with types I, II, III, V, and XI known to form fibers. These types of collagen typically self-assemble into periodic, transversely striated fibers that can reach centimeters in length and tens of microns in diameters. Type I collagen, predominant in fiber formation, is found in bones, skin, teeth, and tendons, while

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.