title: Injectable gels for tissue engineering.
abstract: Recently, tissue engineering approaches using injectable, in situ gel forming systems have been reported. In this review, the gelation processes and several injectable systems that exhibit in situ gel formation at physiological conditions are discussed. Applications of selected injectable systems (alginate, chitosan, hyaluronan, polyethylene oxide/polypropylene oxide) in tissue engineering are also described. Injectable polymer formulation can gel in vivo in response to temperature change (thermal gelation), pH change, ionic cross-linking, or solvent exchange. Kinetics of gelation is directly affected by its mechanism. Injectable formulations offer specific advantages over preformed scaffolds such as: possibility of a minimally invasive implantation, an ability to fill a desired shape, and easy incorporation of various therapeutic agents. Several factors need to be considered before an injectable gel can be selected as a candidate for tissue engineering applications. Apart from tissue-specific cell-matrix interactions, the following gel properties need to be considered: gelation kinetics, matrix resorption rate, possible toxicity of degradation products and their elimination routes, and finally possible interference of the gel matrix with histogenesis.
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington 99352, USA. anna..gustowska@pnl.gov
authors.forename: A
authors.initials: A
authors.lastname: Gutowska
authors.forename: B
authors.initials: B
authors.lastname: Jeong
authors.forename: M
authors.initials: M
authors.lastname: Jasionowski
mesh_terms: D000464:Alginates / Q000008:administration & dosage; D000818:Animals; D021522:Bioartificial Organs; D001672:Biocompatible Materials / Q000008:administration & dosage*; D001698:Biomedical Engineering / Q000379:methods*; D002686:Chitin / Q000008:administration & dosage / Q000031:analogs & derivatives; D048271:Chitosan; D005782:Gels / Q000008:administration & dosage*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage; D007267:Injections; D011092:Polyethylene Glycols / Q000008:administration & dosage; D011108:Polymers / Q000008:administration & dosage; D011409:Propylene Glycols / Q000008:administration & dosage
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D005782:Gels; D006603:Hexuronic Acids; D011108:Polymers; D011409:Propylene Glycols; D002686:Chitin; C012504:polypropylene glycol; D011092:Polyethylene Glycols; D020723:Glucuronic Acid; D006820:Hyaluronic Acid; D048271:Chitosan