A hydrogel is a biphasic material, a mixture of porous, permeable solids and at least 10% by weight or volume of interstitial fluid composed completely or mainly by water. In hydrogels the porous permeable solid is a water insoluble three dimensional network of natural or synthetic polymers and a fluid, having absorbed a large amount of water or biological fluids. These properties underpin several applications, especially in the biomedical area. Many hydrogels are synthetic, but some are derived from nature. The term 'hydrogel' was coined in 1894.
Alginic acid, also called algin, is a naturally occurring, edible polysaccharide found in brown algae. It is hydrophilic and forms a viscous gum when hydrated. With metals such as sodium and calcium, its salts are known as alginates. Its colour ranges from white to yellowish-brown. It is sold in filamentous, granular, or powdered forms.
pH sensitive or pH responsive polymers are materials which will respond to the changes in the pH of the surrounding medium by varying their dimensions. Materials may swell, collapse, or change depending on the pH of their environment. This behavior is exhibited due to the presence of certain functional groups in the polymer chain. pH-sensitive materials can be either acidic or basic, responding to either basic or acidic pH values. These polymers can be designed with many different architectures for different applications. Key uses of pH sensitive polymers are controlled drug delivery systems, biomimetics, micromechanical systems, separation processes, and surface functionalization.
A nerve guidance conduit is an artificial means of guiding axonal regrowth to facilitate nerve regeneration and is one of several clinical treatments for nerve injuries. When direct suturing of the two stumps of a severed nerve cannot be accomplished without tension, the standard clinical treatment for peripheral nerve injuries is autologous nerve grafting. Due to the limited availability of donor tissue and functional recovery in autologous nerve grafting, neural tissue engineering research has focused on the development of bioartificial nerve guidance conduits as an alternative treatment, especially for large defects. Similar techniques are also being explored for nerve repair in the spinal cord but nerve regeneration in the central nervous system poses a greater challenge because its axons do not regenerate appreciably in their native environment.
Biodegradable polymers are a special class of polymer that breaks down after its intended purpose by bacterial decomposition process to result in natural byproducts such as gases (CO2, N2), water, biomass, and inorganic salts. These polymers are found both naturally and synthetically made, and largely consist of ester, amide, and ether functional groups. Their properties and breakdown mechanism are determined by their exact structure. These polymers are often synthesized by condensation reactions, ring opening polymerization, and metal catalysts. There are vast examples and applications of biodegradable polymers.
Dame Athene Margaret Donald is a British physicist. She is Professor Emerita of Experimental Physics at the University of Cambridge, and Master of Churchill College, Cambridge.
A nanodisc is a synthetic model membrane system which assists in the study of membrane proteins. Nanodiscs are discoidal proteins in which a lipid bilayer is surrounded by molecules that are amphipathic molecules including proteins, peptides, and synthetic polymers. It is composed of a lipid bilayer of phospholipids with the hydrophobic edge screened by two amphipathic proteins. These proteins are called membrane scaffolding proteins (MSP) and align in double belt formation. Nanodiscs are structurally very similar to discoidal high-density lipoproteins (HDL) and the MSPs are modified versions of apolipoprotein A1 (apoA1), the main constituent in HDL. Nanodiscs are useful in the study of membrane proteins because they can solubilise and stabilise membrane proteins and represent a more native environment than liposomes, detergent micelles, bicelles and amphipols.
A fibrin scaffold is a network of protein that holds together and supports a variety of living tissues. It is produced naturally by the body after injury, but also can be engineered as a tissue substitute to speed healing. The scaffold consists of naturally occurring biomaterials composed of a cross-linked fibrin network and has a broad use in biomedical applications.
Jindřich Henry Kopeček was born in Strakonice, Czech Republic, as the son of Jan and Herta Zita (Krombholz) Kopeček. He is distinguished professor of pharmaceutical chemistry and distinguished professor of biomedical engineering at the University of Utah in Salt Lake City, Utah. Kopeček is also an honorary professor at Sichuan University in Chengdu, China. His research focuses on biorecognition of macromolecules, bioconjugate chemistry, drug delivery systems, self-assembled biomaterials, and drug-free macromolecular therapeutics.
Self-healing hydrogels are a specialized type of polymer hydrogel. A hydrogel is a macromolecular polymer gel constructed of a network of crosslinked polymer chains. Hydrogels are synthesized from hydrophilic monomers by either chain or step growth, along with a functional crosslinker to promote network formation. A net-like structure along with void imperfections enhance the hydrogel's ability to absorb large amounts of water via hydrogen bonding. As a result, hydrogels, self-healing alike, develop characteristic firm yet elastic mechanical properties. Self-healing refers to the spontaneous formation of new bonds when old bonds are broken within a material. The structure of the hydrogel along with electrostatic attraction forces drive new bond formation through reconstructive covalent dangling side chain or non-covalent hydrogen bonding. These flesh-like properties have motivated the research and development of self-healing hydrogels in fields such as reconstructive tissue engineering as scaffolding, as well as use in passive and preventive applications.
Steven Peter Armes is a Professor of polymer chemistry and colloid chemistry at the University of Sheffield.
Molly S. Shoichet, is a Canadian science professor, specializing in chemistry, biomaterials and biomedical engineering. She was Ontario's first Chief Scientist. Shoichet is a biomedical engineer known for her work in tissue engineering, and is the only person to be a fellow of the three National Academies in Canada.
Matthew V. Tirrell is an American chemical engineer. In 2011 he became the founding Pritzker Director and dean of the Institute for Molecular Engineering (IME) at the University of Chicago, in addition to serving as senior scientist at Argonne National Laboratory. Tirrell's research specializes in the manipulation and measurement of polymer surface properties, polyelectrolyte complexation, and biomedical nanoparticles.
Adisa Azapagić is a chemical engineer and academic. She has served as Professor of Sustainable Chemical Engineering at the University of Manchester since 2006.
Julie Elizabeth Gough is a Professor of Biomaterials and Tissue Engineering at The University of Manchester. She specializes on controlling cellular responses at the cell-biomaterial interface by engineering defined surfaces for mechanically sensitive connective tissues.
Kristi Lynn Kiick is the Blue and Gold Distinguished Professor of Materials Science and Engineering at the University of Delaware. She studies polymers, biomaterials and hydrogels for drug delivery and regenerative medicine. She is a Fellow of the American Chemical Society, the American Institute for Medical and Biological Engineering, and of the National Academy of Inventors. She served for nearly eight years as the deputy dean of the college of engineering at the University of Delaware.
Surita Bhatia is an American chemist who is professor and vice provost of faculty affairs at Stony Brook University. Her work considers the structure of soft materials, including polymeric hydrogels and colloidal glasses. She was elected Fellow of the American Institute of Chemical Engineers, the American Institute for Medical and Biological Engineering and the Society of Rheology in 2020.
Melissa Louise Mather is an Australian physicist who is Professor in Biological Sensing and Imaging at the University of Nottingham. Her research considers the development of novel sensing techniques, including ultrasound, single molecule imaging and nitrogen-vacancy centers in diamond.
Vitaliy Khutoryanskiy FRSC is a British and Kazakhstani scientist, a Professor of Formulation Science and a Royal Society Industry Fellow at the University of Reading. His research focuses on polymers, biomaterials, nanomaterials, drug delivery, and pharmaceutical sciences. Khutoryanskiy has published over 200 original research articles, book chapters, and reviews. His publications have attracted > 11000 citations and his current h-index is 50. He received several prestigious awards in recognition for his research in polymers, colloids and drug delivery as well as for contributions to research peer-review and mentoring of early career researchers. He holds several honorary professorship titles from different universities.
Tatiana Segura is an American biomedical engineer who is a professor at Duke University. Her research considers biomedical engineering solutions to promote cell growth. She was elected Fellow of the American Institute for Medical and Biological Engineering in 2017 and awarded the Acta Biomaterialia Silver Medal in 2021.
