Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When dissolved in aqueous solutions, sodium hyaluronate substituted with low amounts of alkyl chains [amphiphilic hyaluronate (HA)] can give rise to hydrogels thanks to intermolecular reversible hydrophobic interactions, leading to a three-dimensional (3D) network. Such hydrogels possess shear-thinning properties and can thus be injected in cartilage defect to promote chondrocyte proliferation and cartilage repair. However, these hydrogels are only physically crosslinked and can progressively loose their 3D structure when they are in contact with aqueous fluids. To overcome this drawback, HA derivatives substituted with dodecyl chains were chemically crosslinked by a difunctional reagent, tetraethylene glycol ditosylate (TEG-diOTs). To preserve the shear-thinning properties of amphiphilic HA, small amounts of TEG-diOTs were used so as to obtain a low chemical crosslinking ratio. After optimization of the synthesis parameters, aqueous solutions of the HA derivatives, crosslinked both physically and chemically, were obtained, with rheological properties improved compared to the amphiphilic polymers. As the hydrogels are aimed to cartilage repair, they were sterilized by wet heating; the effect of this treatment on the polymer characteristics was analyzed by different techniques. A similar study was carried out on HA derivatives stored under conditions mimicking physiological ones.
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PMID:New physically and chemically crosslinked hyaluronate (HA)-based hydrogels for cartilage repair. 1627 Mar 49

Nanocomposite double-network hydrogels (ncDN hydrogels) are recently introduced to address the limitations of traditional DN hydrogels, such as the lack of diversity in the network structure and the restricted functionalities. However, two challenges remain, including the time-consuming preparation and the lack of shear-thinning and self-healing properties. Here, our approach to developing versatile ncDN hydrogels is through the use of multiple interfacial crosslinking chemistries (i.e., noncovalent interactions of electrostatic interaction and hydrogen bonds as well as dynamic covalent interactions of imine bonds and boronate ester bonds) and surface functionalized nanomaterials (i.e. phenylboronic acid modified reduced graphene oxide (PBA-rGO)). PBA-rGO was used as a multivalent gelator to further crosslink the two polymer chains (i.e. triethylene glycol-grafted chitosan (TEG-CS) and polydextran aldehyde (PDA)) in DN hydrogels, forming the TEG-CS/PDA/PBA-rGO ncDN hydrogels in seconds. The microstructures (i.e. pore size) and properties (i.e. rheological, mechanical, and swelling properties) of the ncDN hydrogels can be simply modulated by changing the amount of PBA-rGO. The dynamic bonds in the polymeric network provided the shear-thinning and self-healing properties to the ncDN hydrogels, allowing the hydrogels to be injected and molded into varied shapes as well as self-repair the damaged structure. Besides, the designed TEG-CS/PDA/PBA-rGO ncDN hydrogels were cytocompatible and also exhibited antibacterial activity. Taken together, we hereby provide a nanomaterial approach to fabricate a new class of ncDN hydrogels with tailorable networks and favorite properties for specific applications.
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PMID:In situ formation of nanocomposite double-network hydrogels with shear-thinning and self-healing properties. 3330 Sep 14