title: Injectable hydrogels derived from phosphorylated alginic acid calcium complexes.
abstract: Phosphorylation of sodium alginate salt (NaAlg) was carried out using H3PO4/P2O5/Et3PO4 followed by acid-base reaction with Ca(OAc)2 to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for (1)H, and (31)P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2w/v%) with NaAlg solution (2w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO4 or CaCl2 were added externally. The gelation was completed within about 3-40min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤6.7kPa for compressive strength at break and about 8.4kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100-800μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering.
authors.affiliation: Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Chungnam, Cheonan 330-714, Republic of Korea; Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Chungnam, Cheonan 330-714, Republic of Korea.
authors.forename: Han-Sem
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Chungnam, Cheonan 330-714, Republic of Korea; Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Chungnam, Cheonan 330-714, Republic of Korea. Electronic address: minsoosong00@gmail.com.
authors.forename: Minsoo
authors.initials: M
authors.lastname: Song
authors.affiliation: Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Chungnam, Cheonan 330-714, Republic of Korea; Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Chungnam, Cheonan 330-714, Republic of Korea.
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Chungnam, Cheonan 330-714, Republic of Korea; Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Chungnam, Cheonan 330-714, Republic of Korea. Electronic address: usshin12@dankook.ac.kr.
authors.forename: Ueon Sang
authors.initials: US
authors.lastname: Shin
mesh_terms: D016475:3T3 Cells; D000464:Alginates / Q000737:chemistry* / Q000494:pharmacology*; D000818:Animals; D002470:Cell Survival / Q000187:drug effects*; D019245:Compressive Strength; D055119:Elastic Modulus; D020723:Glucuronic Acid / Q000737:chemistry / Q000494:pharmacology; D006244:Hardness; D006603:Hexuronic Acids / Q000737:chemistry / Q000494:pharmacology; D020100:Hydrogels / Q000008:administration & dosage* / Q000737:chemistry*; D007267:Injections; D008422:Materials Testing; D051379:Mice; D010766:Phosphorylation; D014783:Viscosity
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020100:Hydrogels; D020723:Glucuronic Acid
keywords: Cell and drug delivery; In vivo injectable hydrogel; Phosphorylated alginic acid calcium complexes