Natural‐Based Hydrogels: From Processing to Applications

Abstract

Natural‐based hydrogels have been widely used for tissue engineering and regenerative medicine (TERM) as a platform to better mimic the native extracellular matrix of different tissues. Polysaccharides and proteins of natural origin have been functionalized, tuned, and processed used different methods to produce different scaffolds and medical devices. Herein, the recent reports dealing with the application of natural‐based hydrogels in TERM strategies are overviewed. Moreover, different methodologies used to process the polymeric hydrogels are also described as well as the most relevant strategies used within the scope of TERM.

Potential of Oil Palm Empty Fruit Bunch Resources in Nanocellulose Hydrogel Production for Versatile Applications: A Review

“…A piezoelectrical actuator or heat breaks the hydrogel into droplets (15 to several hundred microns) and the droplet falls on the building bed by gravitational pulls. However, a large and complex hydrogel product is not preferred and a piezoelectric actuator or electrical heating may be used to create pressure to eject the droplets [120].…”

Angiogenic Potential in Biological Hydrogels

“…Because they all have distinctive characteristics to better suit the final application to achieve different purposes it is possible to choose between various types of hydrogels. Natural hydrogels are usually classified in three main categories: (i) polysaccharides-based, (ii) protein-based and (iii) derived from cellularized tissues [ 16 , 21 , 26 , 27 ].…”

“…GAGs are long linear polysaccharides. Their structure comprises repeated disaccharide units which can be sulfated, such as heparin, heparan sulfate, keratan sulfate and chondroitin sulfate or nonsulfated, as HA [ 27 ]. Depending on the type, the functions of GAGs can change, however they generally affect cell migration, survival and signaling.…”

“…Composed by repeated disaccharide units consisting of N-acetylglucosamine and D-glucuronic acid, HA is a linear high molecular weight (about 10 7 kDa) non-sulfated GAG present in the ECM. Its role consists of a space filler, as a lubricant and helps the processes of wound healing, angiogenesis, and signal transduction [ 21 , 27 ]. HA is characterized by a high biodegradability, biocompatibility, high viscoelasticity and hydrophilia, moreover, it can bind water forming hydrogen bonds with the solvent [ 31 ].…”

“…HA enzymatic degradation produces fragments of the molecule, called hyaluronan oligosaccharides, of less than 10 disaccharide units, that have shown to promote angiogenesis and wound healing [ 32 , 33 ]. However, since native HA is vulnerable to degradation by hyaluronidase or reactive oxygen species, it is necessary to chemically modify the hydrogel [ 27 ], because otherwise the degradation time of the HA scaffold will be faster than the regeneration of the tissue. Modifications can be different: β-cyclodextrin-modified HA (CD-HA) [ 34 , 35 ], adamantane-modified HA (Ad-HA), acrylated HA (AHA) [ 36 , 37 ], dextran-HA (Dex-g-HA) [ 38 ], catechol-HA (CA-HA) [ 29 ] and methacrylate-modified HA (HAM) [ 29 , 39 ].…”