Introductory Chapter: Hydrogels - From First Natural Hydrocolloids to Smart Biomaterials (original) (raw)
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Hydrogels: Properties and Applications in Biomedicine
Molecules
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 th...
25th Anniversary Article: Rational Design and Applications of Hydrogels in Regenerative Medicine
Advanced Materials, 2014
Hydrogels are three-dimensional (3D) networks consisting of hydrophilic polymer chains, which are crosslinked to form matrices with high water content (up to thousand of times their dry weight). [ 1 ] Due to their remarkable characteristics, including tunable physical, chemical, and biological properties, high biocompatibility, versatility in fabrication, and similarity to native extracellular matrix (ECM), hydrogels have emerged as promising materials in the biomedical fi eld. [ 1-3 ] Signifi cant progress has been made in the synthesis and fabrication of hydrogels from both natural and synthetic sources for various applications; these include regenerative medicine, drug/gene delivery, stem cell and cancer research, and cell therapy. [ 4-6 ] Naturally-derived hydrogels, such as collagen, chitosan, hyaluronic acid (HA), alginate, gelatin, elastin, chondroitin sulfate, and heparin, are appealing for biological applications due to their cell signaling and cell-interactive properties, and biodegradability. [ 7 ] However, their limitations include low mechanical properties, inability to control their degradation and structure, and potential immunogenicity. On the other hand, synthetic hydrogels, such as poly(ethylene glycol) (PEG), poly(vinyl alcohol)(PVA), poly(2-hydroxyethyl methacrylate) (PHEMA), and polyacrylamide (PAM), possess controllable degradation and microstructure, generally show high mechanical properties, but lack biological moieties. [ 3,7 ] Due to the distinct properties of each of these hydrogel classes, gels that are based on the combination of natural and synthetic polymers have attracted signifi cant attention for biological and biomedical applications. [ 8 ] Various crosslinking approaches, including chemical and physical, have been employed to create polymer networks and preserve their 3D structures in aqueous environments. In physically crosslinked gels, physical interactions between polymer chains prevent dissociation of the hydrogel, while in chemically crosslinked gels, covalent bonds between polymer chains create stable hydrogels. Physically crosslinked hydrogels are formed through changes in environmental conditions (e.g., pH, temperature, and ionic interactions), hydrogen bonds, Hydrogels are hydrophilic polymer-based materials with high water content and physical characteristics that resemble the native extracellular matrix. Because of their remarkable properties, hydrogel systems are used for a wide range of biomedical applications, such as three-dimensional (3D) matrices for tissue engineering, drug-delivery vehicles, composite biomaterials, and as injectable fi llers in minimally invasive surgeries. In addition, the rational design of hydrogels with controlled physical and biological properties can be used to modulate cellular functionality and tissue morphogenesis. Here, the development of advanced hydrogels with tunable physiochemical properties is highlighted, with particular emphasis on elastomeric, light-sensitive, composite, and shape-memory hydrogels. Emerging technologies developed over the past decade to control hydrogel architecture are also discussed and a number of potential applications and challenges in the utilization of hydrogels in regenerative medicine are reviewed. It is anticipated that the continued development of sophisticated hydrogels will result in clinical applications that will improve patient care and quality of life.
Arabian Journal of Chemistry , 2024
Hydrogels are three-dimensional structures that serve as substitutes for the extracellular matrix (ECM) and possess outstanding physicochemical and biochemical characteristics. They are gaining importance in regenerative medicine because of their similarity to the natural extracellular matrix in terms of moisture content and wound and tissue healing permeability. Tissue engineering advancements have resulted in the development of flexible hydrogels that mimic the dynamic characteristics of the ECM. Several approaches have been applied to produce hydrogels from biopolymers with enhanced functional and structural characteristics for different applications in tissue engineering and regenerative medicine (TERM). This review provides a comprehensive overview of hydrogel in wound healing, tissue engineering, and drug delivery systems. We outline different types of hydrogels based on the physical and chemical crosslinking, fundamental properties, and their applications in TERM. This review article provided the recent literature on hydrogels for tissue engineering and regenerative medicine within five years. Recent developments in biopolymer-based hydrogels for state-of-the-art tissue engineering and regenerative medicine have been discussed, emphasizing their significant challenges and future perspectives.
Recent Advances in Hydrogels for Biomedical Applications
Asian Journal of Pharmaceutical and Clinical Research
Hydrogels are three-dimensional polymeric network, capable of entrapping substantial amounts of fluids. Hydrogels are formed due to physical or chemical cross-linking in different synthetic and natural polymers. Recently, hydrogels have been receiving much attention for biomedical applications due to their innate structure and compositional similarities to the extracellular matrix. Hydrogels fabricated from naturally derived materials provide an advantage for biomedical applications due to their innate cellular interactions and cellular-mediated biodegradation. Synthetic materials have the advantage of greater tunability when it comes to the properties of hydrogels. There has been considerable progress in recent years in addressing the clinical and pharmacological limitations of hydrogels for biomedical applications. The primary objective of this article is to review the classification of hydrogels based on their physical and chemical characteristics. It also reviews the technologie...
Hydrogels for Pharmaceutical and Biomedical Applications
Critical Reviews in Therapeutic Drug Carrier Systems, 2005
Hydrogels are crosslinked hydrophilic polymer structures that can imbibe large amounts of water or biological fl uids. Hydrogels are one of the upcoming classes of polymer-based systems that embrace numerous biomedical and pharmaceutical applications. Th is review discusses various parameters of hydrogels such as surface properties, water content and swelling behavior, eff ect of nature of polymer, ionic content, and thermodynamics, all of which can infl uence the biomedical usage of hydrogels. Meanwhile, intelligent or environment-sensitive hydrogels and bioadhesive hydrogels continue to be important materials for medical applications; therefore, a part of this review is devoted to some of their important classes. Hydrogels are extensively used for various biomedical applications-tissue engineering, molecular imprinting, wound dressings materials, immunoisolation, drug delivery, etc. Th us, this review aims to throw light on immense AU: "THE NUMEROUS"? applications that hydrogels have in the biomedical arena.
Biomedical applications of hydrogels: A review of patents and commercial products
European Polymer Journal, 2014
Hydrogels have become very popular due to their unique properties such as high water content, softness, flexibility and biocompatibility. Natural and synthetic hydrophilic polymers can be physically or chemically cross-linked in order to produce hydrogels. Their resemblance to living tissue opens up many opportunities for applications in biomedical areas. Currently, hydrogels are used for manufacturing contact lenses, hygiene products, tissue engineering scaffolds, drug delivery systems and wound dressings. This review provides an analysis of their main characteristics and biomedical applications. From Wichterle's pioneering work to the most recent hydrogel-based inventions and products on the market, it provides the reader with a detailed introduction to the topic and perspective on further potential developments.
Drug Delivery Strategies and Biomedical Significance of Hydrogels: Translational Considerations
Pharmaceutics, 2022
Hydrogels are a promising and attractive option as polymeric gel networks, which have immensely fascinated researchers across the globe because of their outstanding characteristics such as elevated swellability, the permeability of oxygen at a high rate, good biocompatibility, easy loading, and drug release. Hydrogels have been extensively used for several purposes in the biomedical sector using versatile polymers of synthetic and natural origin. This review focuses on functional polymeric materials for the fabrication of hydrogels, evaluation of different parameters of biocompatibility and stability, and their application as carriers for drugs delivery, tissue engineering and other therapeutic purposes. The outcome of various studies on the use of hydrogels in different segments and how they have been appropriately altered in numerous ways to attain the desired targeted delivery of therapeutic agents is summarized. Patents and clinical trials conducted on hydrogel-based products, a...
Editorial: Biopolymer-Based Hydrogels – Ubiquitous and Prospective Materials
Frontiers in Materials, 2020
Editorial on the Research Topic Biopolymer-Based Hydrogels-Ubiquitous and Prospective Materials Although hydrogels have been of both scientific and technical interest for a very long time, research into these compounds is very far from complete. Indeed, we can witness widespread research efforts to upgrade hydrogels into ever more sophisticated materials, with synthetic and physical chemists striving to make hydrogel structures and properties ever more complex and more ingenious (De France et al., 2018; Raghuwanshi and Garnier, 2019). Modern researchers are trying to make hydrogels more and more similar to materials found in biological bodies, with the aim of enabling such hydrogels to effectively mimic their bio-counterparts and thereby become available for increasingly advanced use in medicine (