Thermo-sensitive alginate-based injectable hydrogel for tissue engineering

• Published in: Carbohydrate polymers 2012-01, Vol.87 (2), p.1515-1521
• Main Authors: Tan, Rongwei, She, Zhending, Wang, Mingbo, Fang, Zhou, Liu, Yuansheng, Feng, Qingling
• Format: Article
• Language: English
• Subjects: Alginate; Alginic acid; amides; Applied sciences; Biological and medical sciences; Carbohydrates; composite polymers; Copolymers; Cytotoxicity; Encapsulation; Exact sciences and technology; Fourier transform infrared spectroscopy; humans; hydrocolloids; Hydrogel; hydrogels; Injectable; loss modulus; Medical sciences; Mesenchyme; monitoring; N.M.R; Natural polymers; nuclear magnetic resonance spectroscopy; Pharmaceuticals; Physicochemistry of polymers; Starch and polysaccharides; Stem cells; storage modulus; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Technology. Biomaterials. Equipments; temperature; Temperature effects; Thermo-sensitive; Tissue engineering; viability; Viscosity; weight loss
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2011.09.048

► A thermo-sensitive comb-like polymer with alginate as the backbone and PNIPAAm as pendant group. ► Thermo-sensitive injectable hydrogel with LCST around 35°C. ► Degradation can be controlled by PNIPAAm modification. ► The entrapped cells in hydrogel preserves good viability and proliferate well. A thermo-sensitive comb-like copolymer was synthesized by grafting PNIPAAm-COOH with a single carboxy end group onto aminated alginate (AAlg) through amide bond linkages. In the copolymer, alginate was the backbone and poly(N-isopropylacrylamide) (PNIPAAm) was the pendant group. The structures of AAlg and three AAlg-g-PNIPAAm copolymers with different PNIPAAm grafting ratios were determined by FTIR and 1H NMR. The rheological properties of AAlg-g-PNIPAAm copolymer hydrogels were measured by monitoring the viscosity, storage modulus and loss modulus as a function of temperature. The lower critical solution temperature of AAlg-g-PNIPAAm copolymers was measured as 35°C through rheological analysis. An in vitro degradation study was carried out by monitoring weight loss. It was confirmed that degradation can be controlled by PNIPAAm modification. Encapsulation of human bone mesenchymal stem cells (hBMSCs) within hydrogels showed that the AAlg-g-PNIPAAm copolymer was not cytotoxic and preserved the viability of the entrapped cells well. The thermo-sensitive AAlg-g-PNIPAAm copolymer has attractive properties that make it suitable as cell or pharmaceutical delivery vehicles for a variety of tissue engineering applications.