# The Long and Winding Road to Cardiac Regeneration
## 4 Biomaterials
### Natural Biomaterials  
Natural biomaterials are a group of substances derived from biological sources holding a significant promise in the field of cardiac tissue engineering. These biomaterials play a crucial role in supplementing existing tissue and providing a favorable environment for cellular growth and tissue regeneration. They offer distinct advantages over synthetic materials due to their biocompatibility, biodegradability, and ability to mimic the extracellular matrix (ECM) found in native tissues [179]. \begin{table}
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**Biomaterial** & **Source** & **Advantages** & **Formulation** & **Properties and Functions** & **Refs.** \\ \hline Polyurethane (PUR) & Synthetic polymer & Biocompatibility, high flexibility, plasticity, elasticity, durability & Biomimetic scaffolds & Mimic the mechanical behavior of cardiac tissue, support cell adhesion, proliferation, and differentiation & [191; 192; 193; 194; 195; 196; 197; 198] \\ \hline Polyethylene glycol (PEG) & Synthetic polymer derived from chemical modification of petroleum & Biocompatibility, hydrophilic, low immunogenicity and mechanical strength & & Support cell adhesion, survival and tissue maturation & [199; 200; 201; 202] \\ \hline Poly(\(\varepsilon\)-caprolactone) (PCL) & Synthetic polymer from the polymerization of \(\varepsilon\)-caprolactone monomers of \(\varepsilon\)-caprolactone monomers & Biodegradability, biocompatibility and processability & Cardiac tissue constructs & Support cell adhesion, proliferation and differentiation & [203; 204; 205; 206] \\ \hline Poly(lactic-co-glycolic acid) (PLGA) & Synthetic polymer from a combination of lactic acid and glycolic acid & Biodegradability, biocompatibility & Fibers, films and scaffolds (cardiac patches) & Provide mechanical support forcel attachment and proliferation & [207; 208; 209; 210] \\ \hline Poly(l-lactide) (PLA) & Synthetic polymer derived from lactic acid & Biocompatibility, low cytotoxicity, high mechanical strength & Fibers, films and scaffolds (cardiac patches) & Support cell attachment, growth, proliferation, and differentiation & [211; 212; 213] \\ \hline Poly(glycerol sequence) & Synthetic polymer from glycerol and (PCS) & High elasticity, biodegradability, from glycerol and mechanical properties & Cardiac patches, bioartificial, myocardium, and cardiovascular & Promote cell growth, enhance contractile function, and improve cardiac tissue & [214; 215; 216; 217] \\ \hline \hline \end{tabular} The table summarizes synthetic biomaterials for cardiac regeneration purpose, their features, and the formulation available.  
\end{table} 
Table 2: Synthetic biomaterials. Various natural biomaterials have been extensively studied. Among the protein-based materials, collagen, fibrin, gelatin, and silk have garnered considerable attention [218]. Collagen, the most abundant protein in the human body, provides structural integrity and supports cell adhesion and migration. Fibrin, derived from the clotting protein fibrinogen, possesses excellent biocompatibility, and promotes cell attachment and proliferation. Gelatin, derived from collagen through a controlled degradation process, exhibits similar characteristics and supports cell growth. Silk, a natural fibrous protein, offers exceptional mechanical properties and biodegradability, making it an attractive option for cardiac scaffold fabrication [176]. Polysaccharides, another class of natural biomaterials, have also been extensively explored in cardiac tissue engineering. Chitosan, derived from chitin, a component of crustacean shells, exhibits antibacterial properties, good mechanical strength, and biocompatibility. Alginate, extracted from brown seaweed, forms gel-like structures suitable for cell encapsulation and protection. Hyaluronic acid, a major component of the ECM, plays a crucial role in tissue hydration, cell migration, and wound healing.