Versatility of Hydrogels: From Synthetic Strategies, Classification, and Properties to Biomedical Applications

Abstract

Hydrogels are three-dimensional, cross-linked, and supramolecular networks that can absorb significant volumes of water. Hydrogels are one of the most promising biomaterials in the biological and biomedical fields, thanks to their hydrophilic properties, biocompatibility, and wide therapeutic potential. Owing to their nontoxic nature and safe use, they are widely accepted for various biomedical applications such as wound dressing, controlled drug delivery, bone regeneration, tissue engineering, biosensors, and artificial contact lenses. Herein, this review comprises different synthetic strategies for hydrogels and their chemical/physical characteristics, and various analytical, optical, and spectroscopic tools for their characterization are discussed. A range of synthetic approaches is also covered for the synthesis and design of hydrogels. It will also cover biomedical applications such as bone regeneration, tissue engineering, and drug delivery. This review addressed the fundamental, general, and applied features of hydrogels in order to facilitate undergraduates, graduates, biomedical students, and researchers in a variety of domains.

Hydrogels in Spinal Cord Injury Repair: A Review

“…Ideally, a nerve tissue scaffold would serve as a carrier of seed cells and active factors while also filling the lesion site, assisting seed cell survival and proliferation, promoting the reconnection of damaged spinal cord tissue, helping to bridge the gap in the lesion site and rebuild nerve conduction, and facilitating sustained drug delivery. The scaffolds most used for nerve repair include hydrogels, nanoparticles, and nanofibers ( Ahmad et al, 2022 ). In this paper, we describe the characteristics of hydrogels and discuss their applications in SCI repair.…”

Extracellular Optogenetics at the Interface of Synthetic Biology and Materials Science

“…Unlike natural polymers, synthetic analogs cannot provide biochemical cues to facilitate cell signaling; however, signaling molecules such as peptides, growth factors, and glycans can be incorporated within OptoGels to recapitulate natural extracellular environments ( Nicolas et al (2020) ). Synthetic polymer networks that could be good candidates for future opto-enabled materials include several that are currently used in hydrogels for biomedical applications: polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyhydroxyethylmethacrylate (pHEMA), polyacrylamide (PAAm), and poly (N′-isopropylacrylamide) (pNIPAm) ( Ahmad et al (2022) ). However, among these polymer networks only variants of PEG have been used in OptoGels.…”

“…Conventional biomaterials have mainstream uses ranging from wound dressing, to cell culture substrates, to medical device coatings, but have historically lacked dynamic spatiotemporal control ( Ahmad et al (2022) ). Besides their uses in materials, optoproteins have been used in a variety of other extracellular contexts that are outside of the scope of this review.…”

Milk Protein-Based Nanohydrogels: Current Status and Applications

“…Hydrophilic gels, or more commonly designated as hydrogels, are three-dimensional networks of polymers that can swell in water and have the potential to retain a high amount within their structure without dissolving [ 1 ]. The history of the development of hydrogels is grouped into three generations: first-generation or conventional super-porous hydrogels, and second-generation and third-generation hydrogels [ 2 ].…”

“…Due to the unique functional properties, hydrogels discover likely applications in biomedical engineering (drug conveyance, tissue designing, and drug discharge) [ 10 ], medical science, agriculture (soil moisturizing, nutrient carrier, and erosion control) [ 11 ], textiles, construction [ 12 ], diagnostics, regenerative medicines [ 13 ], electrical [ 14 ], flocculation [ 15 ], wastewater treatment, sensors and actuators [ 16 ], personal healthcare and hygiene products [ 17 ], as well as the food industry (food safety, food nutrition, and food engineering). The covalent and noncovalent interactions such as electrostatic interactions, hydrogen bonds, van der Waals interactions, and intermolecular hydrophobic interactions constitute the chemistry of the hydrogels, and the presence of hydroxyl, amines, carboxyl, ethers, and sulfate groups is responsible for soft and pliable structure [ 1 ]. Hydrogels can be synthesized from natural origin (proteins and polysaccharides) as well as synthetic sources (polyvinyl alcohol and polyethylene oxide) [ 18 ].…”