title: Fabrication of positively charged poly(ethylene glycol)-diacrylate hydrogel as a bone tissue engineering scaffold.
abstract: To improve cell attachment and to understand the effects of positive charge on the behavior of osteoblasts, 2-(methacryloyloxy)ethyl-trimethylammonium chloride (MAETAC), a positively charged monomer, was incorporated into poly(ethylene glycol)-diacrylate (PEGDA) hydrogel. The physicochemical properties of the resultant polymers, including the degree of acrylation of PEGDA, pKa of MAETAC, swelling ratio, zeta potential, and protein adsorption were investigated. Meanwhile, osteoblast-like MC3T3-E1 cells were seeded on the hydrogel to evaluate the effect of the positive charge on the behavior of the cells, including attachment, proliferation, and differentiation. The results revealed that PEGDA was synthesized with 90 percent of acrylation and MAETAC had been successfully incorporated into PEGDA. The pKa value of MAETAC was 9.4 determined by acid-based titration. The electrically charged nature of modified hydrogels was confirmed by zeta potential. With increasing concentration of MAETAC, the swelling ratio of the hydrogel in deionized water increased, while the swelling ratio stayed constant in phosphate buffer solution. The protein adsorption of the hydrogel also increased with increasing concentration of MAETAC. The modification of positive charge not only enhanced the attachment and proliferation of osteoblast-like MC3T3-E1 cells on the hydrogel, but also up-regulated alkaline phosphatase activity in the cells as well as gene expression of focal adhesion kinase and osteogenic markers, including collagen I, osteopontin, and osteocalcin. These findings indicate that the positively charged PEGDA may not only be a promising scaffold candidate for bone tissue engineering, but also a good platform to study the effect of positive charge on cell behavior due to the controllable charge density.
authors.affiliation: Hubei-MOST KLOS & KLOBM, School and Hospital of Stomatology, Wuhan University, Wuhan 430079, People's Republic of China. tanf-1984@163.com
authors.forename: Fei
authors.initials: F
authors.lastname: Tan
authors.forename: Xiaoding
authors.initials: X
authors.lastname: Xu
authors.forename: Ting
authors.initials: T
authors.lastname: Deng
authors.forename: Miao
authors.initials: M
authors.lastname: Yin
authors.forename: Xianzheng
authors.initials: X
authors.lastname: Zhang
authors.forename: Jiawei
authors.initials: J
authors.lastname: Wang
mesh_terms: D016475:3T3 Cells; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry*; D002448:Cell Adhesion; D049109:Cell Proliferation; D004563:Electrochemistry; D051417:Focal Adhesion Kinase 1 / Q000235:genetics; D015870:Gene Expression; D020100:Hydrogels; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics; D011092:Polyethylene Glycols / Q000737:chemistry*; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: C120889:2-(trimethylammonio)ethyl methacrylate; D018786:Bone Substitutes; D020100:Hydrogels; D008689:Methacrylates; C437167:poly(ethylene glycol)diacrylate; D011092:Polyethylene Glycols; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse; D000469:Alkaline Phosphatase