2.11 Polymers of Biological Origin ☆

Abstract

Recent advances in tissue engineering and regenerative medicine have shown that combining biomaterials, cells, and bioactive molecules are important to promote the regeneration of damaged tissues or as therapeutic systems. Natural origin polymers have been used as matrices in such applications due to their biocompatibility and biodegradability. This chapter provides an up-to-date review on the most promising natural biopolymers, focused on polysaccharides and proteins, their properties and applications. Membranes, micro/ nanoparticles, scaffolds, and hydrogels as biomimetic strategies for tissue engineering and processing are described, along with the use of bioactive molecules and growth factors to improve tissue regeneration potential. Finally, current biomedical applications are also presented.

Smart Hydrogels in Tissue Engineering and Regenerative Medicine

“…Most of the human cell types require adequate anchorage to support tissue regeneration, and thus the lack thereof may result in cell necrosis and defective tissues. “It is essential for the scaffolds to act as a substrate and have essential physical and chemical properties necessary to promote cell attachment, proliferation, differentiation, and migration” [19]. They deliver cells to the desired size in the patient’s body, provide a space for new tissue formation, and potentially control structural and functional integrity of the newly engineered tissue [20,21].…”

“…Over the years, various polymeric biomaterials have been developed by adding multiple functional groups in their molecular structure to control the physical, chemical, and biological characteristics of these scaffolds [22,23,24,25]. They are processed using materials both natural and synthetic in origin, derived from sources like algae, animals, micro-organisms [19] and synthetic biomaterials derived either from lactic acid, caprolactone, or glycoside monomers [26,27]. Though several scaffold matrices were introduced, which had sufficient qualities to provide necessary support and properties required for tissue growth, they had inadequate cell mimicking property and limited interaction with stromal cells which were crucial in promoting tissue regeneration.…”

Advances in Engineering Human Tissue Models

“…Thus, they can be categorized as natural, synthetic, or hybrid biomaterials (see Table 1 for examples of biomaterials and applications). In most cases, naturally derived biomaterials are amino acid-based or sugar-based biopolymers which can be components of the natural ECM (e.g., collagen, laminin, elastin, and fibrinogen) or not (e.g., chitin, silk fibroin, chitosan, and alginate; Silva et al, 2017 ; Ahadian et al, 2018 ). Such materials represent an attractive source for in vitro TE applications, due to their microstructure, stability, biocompatibility, and ability to present cells with natural adhesion sites, as well as due to the possibility to tailor and control their properties via physical or chemical treatments (i.e., cross-linking) or by blending them with other biopolymers (Guarino et al, 2016 ; Ullah and Chen, 2020 ) to better recapitulate in vitro the physiological milieu.…”

Surface Modification of Bacterial Cellulose for Biomedical Applications

“…Cellulose has become a popular choice for intensive ongoing research and a keen interest has developed on the emerging applications of robust and translucent cellulose and their advanced functionalities in electronics, photonics, energy storage, wearable or injectable device [ 2 , 5 , 6 ]. Bacterial cellulose (BC) is a polysaccharide (C 6 H 10 O 5 ) n , with characteristic microstructures and is derived from microorganisms such as, Gram-negative bacterial species of the genera Gluconacetobacter , Sarcina , Azobacter Achromobacter , Aerobacter , Salmonella , Rhizobium , Pseudomonas and Alcaligenes , as well as oomycetes and green algae [ 7 , 8 , 9 ]. The serendipitous discovery of BC during vinegar fermentation by A. J.…”