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The following article deals with fifth generation biomaterials that are used for bone structure replacement. For any material to be classified for biomedical applications, three requirements must be met. The first requirement is that the material must be biocompatible; it means that the organism should not treat it as a foreign object. Secondly ...
The primary role of many of these polymers was to act as a biocompatible cement in the fixation of prostheses and in the replacement of joints. Newer biologically compatible synthetic and natural biodegradable polymers have been developed; these include polyglycolide, polylactide, polyhydroxobutyrate, chitosan, hyaluronic acid, and hydrogels.
A hydrogel is a biphasic material, a mixture of porous and permeable solids and at least 10% of water or other interstitial fluid. [1] [2] The solid phase is a water insoluble three dimensional network of polymers, having absorbed a large amount of water or biological fluids.
The hydrogel's stiffness can be thousands of times smaller than the dielectric's, allowing actuation without mechanical constraint across a range of nearly 100% at millisecond speeds. They can be biocompatible. [3] [4] Remaining issues include drying of the hydrogels, ionic build-up, hysteresis, and electrical shorting. [3] [4]
SMPs have demonstrated recoverable strains of above 800%. [7] Two important quantities that are used to describe shape-memory effects are the strain recovery rate (R r) and strain fixity rate (R f). The strain recovery rate describes the ability of the material to memorize its permanent shape, while the strain fixity rate describes the ability ...
Specifically, hydrogels can be designed to release drugs or other agents in response to physical characteristics of the environment like temperature and pH. [12] The responsiveness of hydrogels is a result of their molecular structure and polymer networks. [12] Hydrogel nanoparticles have a promising future in the drug delivery field.
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.
Physical hydrogels contain reversible matrices of hydrogen and non-covalent bonds, while chemical hydrogels are composed of irreversible matrices that are molecularly held together by covalent bonds. Used as another parameter in characterizing gels, electric charge (also referred to as ionic character) describes the ability of the ...