Diversity of Bioinspired Hydrogels: From Structure to Applications

Abstract

Hydrogels are three-dimensional networks with a variety of structures and functions that have a remarkable ability to absorb huge amounts of water or biological fluids. They can incorporate active compounds and release them in a controlled manner. Hydrogels can also be designed to be sensitive to external stimuli: temperature, pH, ionic strength, electrical or magnetic stimuli, specific molecules, etc. Alternative methods for the development of various hydrogels have been outlined in the literature over time. Some hydrogels are toxic and therefore are avoided when obtaining biomaterials, pharmaceuticals, or therapeutic products. Nature is a permanent source of inspiration for new structures and new functionalities of more and more competitive materials. Natural compounds present a series of physico-chemical and biological characteristics suitable for biomaterials, such as biocompatibility, antimicrobial properties, biodegradability, and nontoxicity. Thus, they can generate microenvironments comparable to the intracellular or extracellular matrices in the human body. This paper discusses the main advantages of the presence of biomolecules (polysaccharides, proteins, and polypeptides) in hydrogels. Structural aspects induced by natural compounds and their specific properties are emphasized. The most suitable applications will be highlighted, including drug delivery, self-healing materials for regenerative medicine, cell culture, wound dressings, 3D bioprinting, foods, etc.

Self-Healing of Pluronic® F127 Hydrogels in the Presence of Various Polysaccharides

“…An important requirement of injectable hydrogels is self-healing ability; a fast recovering of the non-deformed state once they are injected in the damaged site, avoiding a sudden release of drugs or encapsulated cells after injection [ 24 , 61 , 62 ]. Similarly, it is necessary for 3D printed materials to possess high thixotropy, i.e., the viscosity (or other rheological parameters) quickly decreases when shear forces are applied, and the initial value is recovered very quickly when the shear forces are removed.…”

Progress of Hydrogel Dressings with Wound Monitoring and Treatment Functions

“…Additionally, they ensure safety, ease of removal from the wound’s surface, painless alteration during dressing changes, and simple application. These hydrogels also possess the necessary mechanical strength and viscoelastic attributes, including storage and loss modulus and suture retention strength, rendering them suitable for wound surface suturing or direct application to the wound area [ 24 , 25 , 26 , 27 ]. The hydrogel can form a semi-closed protective film at the injured area, providing a moist and breathable environment for healing and preventing the tissue from drying.…”

Study on Bioresponsive Gelatin-Hyaluronic Acid-Genipin Hydrogel for High Cell-Density 3D Bioprinting

“…They swell, collapse, or degrade over time in response to selective biological environments [ 6 ]. Bioresponsive hydrogels are under extensive research for targeted cell delivery, cancer therapy, drug delivery, tissue engineering, and 3D bioprinting systems with and without scaffolds [ 7 , 8 , 9 ]. Scaffold-based and scaffold-free 3D cell culture systems have been developed to establish related in vitro models replicating the complex structure observed in vivo [ 10 ].…”