title: In situ gelling pH- and temperature-sensitive biodegradable block copolymer hydrogels for drug delivery.
abstract: Stimuli-sensitive injectable polymeric hydrogels have been extensively investigated during the past decade as bioactive agent delivery vehicles and for tissue engineering applications. An aqueous solution of these polymers undergoes a sol-to-gel phase transition in response to external stimuli such as pH, temperature, salt, light, biomolecules, electromagnetic field, etc. Bioactive molecules or cells can be mixed into the low-viscosity state of the polymer solution and injected into the body at a target site, forming an in situ hydrogel depot, which can then serve as bioactive-molecule-releasing carriers or a cell-growing microenvironment. This review systematically summarizes the recent progress in biodegradable and injectable block copolymer hydrogels, giving special attention to the novel and promising pH- and temperature-sensitive injectable block copolymer hydrogels for biomedical applications. The gelation mechanism, formation of ionic complexes, and biodegradation are highlighted as key factors responsible for controlled protein/drug delivery. The advantages and perspectives of pH- and temperature-sensitive injectable block copolymer hydrogels are also highlighted.
authors.affiliation: Theranostic Macromolecules Research Center and School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do, 440-746, South Korea.
authors.forename: Narendra K
authors.initials: NK
authors.lastname: Singh
authors.affiliation: Theranostic Macromolecules Research Center and School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do, 440-746, South Korea. Electronic address: dslee@skku.edu.
authors.forename: Doo Sung
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D065546:Drug Liberation; D019382:Human Growth Hormone / Q000008:administration & dosage; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000008:administration & dosage; D015394:Molecular Structure; D044367:Phase Transition; D011091:Polyesters / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011994:Recombinant Proteins / Q000008:administration & dosage; D013696:Temperature; D000267:Tissue Adhesions
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D020100:Hydrogels; D007328:Insulin; D011091:Polyesters; D011994:Recombinant Proteins; C499774:polyethylene glycol-polylactide-polyethylene glycol; D019382:Human Growth Hormone; D011092:Polyethylene Glycols
keywords: Drug delivery; Injectable hydrogel; Stimuli-sensitive