Hydrogels: Properties and Applications in Biomedicine

Abstract

Hydrogels are crosslinked polymer chains with three-dimensional (3D) network structures, which can absorb relatively large amounts of fluid. Because of the high water content, soft structure, and porosity of hydrogels, they closely resemble living tissues. Research in recent years shows that hydrogels have been applied in various fields, such as agriculture, biomaterials, the food industry, drug delivery, tissue engineering, and regenerative medicine. Along with the underlying technology improvements of hydrogel development, hydrogels can be expected to be applied in more fields. Although not all hydrogels have good biodegradability and biocompatibility, such as synthetic hydrogels (polyvinyl alcohol, polyacrylamide, polyethylene glycol hydrogels, etc.), their biodegradability and biocompatibility can be adjusted by modification of their functional group or incorporation of natural polymers. Hence, scientists are still interested in the biomedical applications of hydrogels due to their creative adjustability for different uses. In this review, we first introduce the basic information of hydrogels, such as structure, classification, and synthesis. Then, we further describe the recent applications of hydrogels in 3D cell cultures, drug delivery, wound dressing, and tissue engineering.

Influence of Gel Stage from Cellulose Dissolution in NaOH-Water System on the Performances of Cellulose Allomorphs-Based Hydrogels

“…It has been observed that the transition process from CI to CII is accompanied by modifications of the intensities corresponding to different crystallographic planes. The diffraction peaks characteristic of CI are presented in Figure 4a and appear at Bragg angles (2θ) of 14.6°, 16.2°, and 22.5°, which are typical for the crystallographic planes, (110), (1)(2)(3)(4)(5)(6)(7)(8)(9)(10), and (200), respectively. In the case of the CII, three characteristic cellulose lattice planes were identified in the XRD diffraction pattern (Figure 4b), and these appear at 12.1° assigned to the (110) plane, at 20.1° for the (1-10) plane, and at 21.8° for (200) plane, respectively.…”

“…Since their development in the late 1960s, hydrogels have distinguished themselves by a network-like three-dimensional (3D) structure, as well as by their unique properties, which gives them competitive advantages compared to the other materials, making them a promising material-platform for various applications [ 1 , 2 , 3 ]. The undeniable versatility of hydrogels in terms of their synthesis, composition, and physical and chemical properties has led to a considerable attention from both research and industry and has created wide applicative potential, from the agricultural and industrial to the biomedical field.…”

A Comprehensive Review of Cross-Linked Gels as Vehicles for Drug Delivery to Treat Central Nervous System Disorders

“…Collagen is one of the major structural elements of extracellular matrix (ECM) in bones, connective, and nerve tissues which are responsible for elastic strength, regulating cell adhesion, chemotaxis, migration, and tissue development. This polymer is the most abundant fibrous protein in the human body [ 90 , 91 ]. Collagen has challenges such as inconsistency, and ethical and cultural issues as they are derived from animal sources.…”

Evaluation of Physically and/or Chemically Modified Chitosan Hydrogels for Proficient Release of Insoluble Nystatin in Simulated Fluids

“…The uniqueness of hydrogels in terms of their physical properties makes them ideal candidates for embedding, carrying and releasing drugs and other biologically active substances [ 13 ]. The ability to absorb large amounts of water and their flexibility are properties that make hydrogels closely resemble biological tissues [ 14 ]. Moreover, another advantage is given by the versatility of preparation methods, as the hydrogels can be obtained either by physical cross-linking (based on the intermolecular hydrophobic interactions, electrostatic attraction or hydrogen bonding), or by permanent chemical cross-linking of the polymer chains through covalent bonding between functional groups [ 15 , 16 ].…”