title: Injectable hydrogel as stem cell scaffolds from the thermosensitive terpolymer of NIPAAm/AAc/HEMAPCL.
abstract: A series of biodegradable thermosensitive copolymers was synthesized by free radical polymerization with N-isopropylacrylamide (NIPAAm), acrylic acid (AAc) and macromer 2-hydroxylethyl methacrylate-poly(ɛ-caprolactone) (HEMAPCL). The structure and composition of the obtained terpolymers were confirmed by proton nuclear magnetic resonance spectroscopy, while their molecular weight was measured using gel permeation chromatography. The copolymers were dissolved in phosphate-buffered saline (PBS) solution (pH = 7.4) with different concentrations to prepare hydrogels. The lower critical solution temperature (LCST), cloud point, and rheological property of the hydrogels were determined by differential scanning calorimetry, ultraviolet-visible spectrometry, and rotational rheometry, respectively. It was found that LCST of the hydrogel increased significantly with the increasing NIPAAm content, and hydrogel with higher AAc/HEMAPCL ratio exhibited better storage modulus, water content, and injectability. The hydrogels were formed by maintaining the copolymer solution at 37°C. The degradation experiment on the formed hydrogels was conducted in PBS solution for 2 weeks and demonstrated a less than 20% weight loss. Scanning electron microscopy was also used to study the morphology of the hydrogel. The copolymer with NIPAAm/AAc/HEMAPCL ratio of 88:9.6:2.4 was bioconjugated with type I collagen for the purpose of biocompatibility enhancement. In-vitro cytotoxicity of the hydrogels both with and without collagen was also addressed.
authors.affiliation: Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, People's Republic of China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Lian
authors.forename: Yan
authors.initials: Y
authors.lastname: Xiao
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Bian
authors.forename: Yu
authors.initials: Y
authors.lastname: Xia
authors.forename: Changfa
authors.initials: C
authors.lastname: Guo
authors.forename: Shenguo
authors.initials: S
authors.lastname: Wang
authors.forename: Meidong
authors.initials: M
authors.lastname: Lang
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000179:Acrylates / Q000737:chemistry*; D000818:Animals; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D020100:Hydrogels / Q000008:administration & dosage* / Q000737:chemistry*; D007267:Injections; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008689:Methacrylates / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D051381:Rats; D033581:Stem Cell Transplantation / Q000295:instrumentation* / Q000379:methods; D054457:Tissue Scaffolds
chemical_list: D000178:Acrylamides; D000179:Acrylates; D020100:Hydrogels; D008689:Methacrylates; D011091:Polyesters; C507887:poly(epsilon-caprolactone) dimethacrylate; C067295:N-isopropylacrylamide; C036658:acrylic acid