China
Africa
Explore chapters and articles related to this topic
Study on the Effect of Hydrogel on Plant Growth
Published in P. C. Thomas, Vishal John Mathai, Geevarghese Titus, Emerging Technologies for Sustainability, 2020
Alvin Joseph, Amitha Anna George, Anu Prakash, M. J. Ashika Gowri, Mini Mathew
PUSA hydrogel is used in the agricultural field. Hydrogel a super absorbent able to retain water and plant nutrients and release it to the plants when surrounding soil near the root zone of plants start to dry up. Hydrogel are three-dimensional, hydrophilic, polymeric networks proficient in absorbing a great amount of water or biological fluids. Owing to their high-water content, porosity and soft consistency, they intently simulate natural living tissue, more so than any other category of synthetic biomaterials [4].
Polymeric Hydrogels for Controlled Drug Delivery
Published in Munmaya K. Mishra, Applications of Encapsulation and Controlled Release, 2019
Hira Ijaz, Farooq Azam, Ume Ruqia Tul-Ain, Junaid Qureshi
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 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, DDS, and wound dressings.
Genetically Engineered Protein Domains as Hydrogel Crosslinks
Published in Raphael M. Ottenbrite, Sung Wan Kim, Polymeric Drugs & Drug Delivery Systems, 2019
Chun Wang, Russell J. Stewart, Russell J. Stewart, Jindrich KopeČek
The most important ways to synthesize hydrogels are crosslinking copolymerization, crosslinking of polymeric precursors, and polymer-polymer reactions. These traditional methods of synthesis have produced numerous materials with excellent properties. However, these synthetic pathways do not permit an exact control of chain length, sequence, and three-dimensional structure. Radical polymerization usually results in a product with a distribution of different molecular weight species. In the case of hydrogels, the main problem is side reactions, such as formation of internal loops, unreacted pendant groups, and entanglements [8]. These defects or heterogeneity in the detailed structure of crosslinked polymers have profound influences on the physicochemical properties and ultimately the biological performances of these biomaterials. For example, biorecognition of ligands in hydrogels by enzymes is influenced by the structure of the ligand, equilibrium degree of swelling, and detailed structure of the network [9]. The detailed structure of hydrogels based on copolymers of N, N-dimethylacrylamide containing azoaromatic groups in the crosslinks depends on the method of synthesis. The structural differences result in different rates of hydrogel degradation by azoreductase in the gastrointestinal tract [8].
A review on the treatment of intimal hyperplasia with perivascular medical devices: role of mechanical factors and drug release kinetics
Published in Expert Review of Medical Devices, 2023
Ankur J. Raval, Jigisha K. Parikh, Meghal A. Desai
Hydrogels are a group of materials mainly consisting of hydrophilic three-dimensional network that readily captures and holds a large amount of water in its polymeric structure. The water content ranges within 70–90%, similar to the tissues in physical terms, and gives them excellent biocompatibility [47]. The hydrophilic network provides a high capacity to encapsulate drugs with similar physicochemical properties. Upon cross-linking, their physical properties change drastically, making them stiff, and their mechanical properties resemble solids which can further be tuned based on the end-user application. For example, the elastic modulus could be adjusted in the range of 0.5 kPa to 5 MPa to resemble the mechanical strength of various soft tissues [48,49]. Based on the end-use application, different hydrogel properties, like size, architectural network, and function, could be tuned to develop unique drug delivery systems. These properties could be adjusted by the material involved (e.g. polymer/copolymers, block-co-polymers), its concentration, molecular weight, and structure [50].
Adsorptive separation of dye by filled polymeric FIPN hydrogel
Published in Indian Chemical Engineer, 2023
Samyabrata Bhattacharjee, Avijit Ghosh, Biswajit Mandal, Sunil Baran Kuila
Hydrogel, a 3-D flexible polymeric network, can exhibit diverse swelling due to different relative populations of hydrophilic groups deriving from differing quantities of additional elements, temperature and synthesis techniques [31]. Crosslinking either synthetic polymers or a mix of synthetic and natural polymers could be used to create hydrogels. In fact, artificial poly-(n) hydrogels typically have excellent mechanical strength but are not degradable [32]. Biopolymer hydrogels, on either hand, are much more degradable but lack mechanical strength [33]. By integrating the characteristics of synthetic and natural polymers, it’ll be possible to achieve an optimal balance between mechanical characteristics and bio-compatibility. In this case, an interpenetrating polymer network (IPN) type hydrogel, crafted by polymerising of one/two synthetic monomer(s) to generate a homo-/co-polymer in the presence of a natural polymer, after which crosslinking one or both polymer(s) for semi-IPN (SIPN) or full-IPN (FIPN) type network formation, can provide the required swell ability and mechanical strength. The following schematic mechanism may help to understand the process of MG like cationic dye adsorption by polymeric hydrogels.
PVA nanocomposite hydrogel loaded with silver nanoparticles enriched Nigella sativa oil
Published in Inorganic and Nano-Metal Chemistry, 2022
Eram Sharmin, Afnan S. Batubara, Bushra Abdulrahman Tamboosi, Elaf Bander Al Khozay, Maha Khalid Alamoudi, Ohoud Zaki Al Aidaroos, Jana Abdullaziz Albenayan, Majd Yousuf Lamfon, Afnan Abdulhamaid Hassan Sindi, Lamiaa A. Al-Madboly, Nagwa A. Shoeib, Manawwer Alam
Hydrogels are smart hydrophilic polymers with three dimensional cross-linked networks. They can retain large volumes of water in their swollen structures when placed in water, and are responsive to external stimuli such as pH, temperature, ionic strength and electric field. Hydrogels’ classification is based on their source (natural or synthetic), configuration, type of cross-linking (chemical or physical nature of the cross-link junctions), physical appearance, methods of preparation, and network electrical charge. Hydrogels find applications in antimicrobial packaging, drug delivery, wound dressings and several other biomedical and pharmaceutical applications. Often, conventional hydrogels bear inferior properties and lack functionalities required for their targeted applications. Thus, hydrogel matrices are loaded with NP as nano fillers/nano reinforcements (e.g., nanoclays, carbon nanotubes, hydroxyapatite, silica, calcium, silver, gold, titania, alumina, and others), producing nanocomposite hydrogels with improved physical, chemical, and biological properties relative to conventional hydrogels, correlated to enhanced interactions between polymer hydrogel backbone/chains and the introduced NP, with promising applications in metal adsorption, sensors, drug delivery, and other biomedical devices.[15–19]