title: Effect of surface modification of nanofibres with glutamic acid peptide on calcium phosphate nucleation and osteogenic differentiation of marrow stromal cells.
abstract: Biomineralization is mediated by extracellular matrix (ECM) proteins with amino acid sequences rich in glutamic acid. The objective of this study was to investigate the effect of calcium phosphate deposition on aligned nanofibres surface-modified with a glutamic acid peptide on osteogenic differentiation of rat marrow stromal cells. Blend of EEGGC peptide (GLU) conjugated low molecular weight polylactide (PLA) and high molecular weight poly(lactide-co-glycolide) (PLGA) was electrospun to form aligned nanofibres (GLU-NF). The GLU-NF microsheets were incubated in a modified simulated body fluid for nucleation of calcium phosphate crystals on the fibre surface. To achieve a high calcium phosphate to fibre ratio, a layer-by-layer approach was used to improve diffusion of calcium and phosphate ions inside the microsheets. Based on dissipative particle dynamics simulation of PLGA/PLA-GLU fibres, > 80% of GLU peptide was localized to the fibre surface. Calcium phosphate to fibre ratios as high as 200%, between those of cancellous (160%) and cortical (310%) bone, was obtained with the layer-by-layer approach. The extent of osteogenic differentiation and mineralization of marrow stromal cells seeded on GLU-NF microsheets was directly related to the amount of calcium phosphate deposition on the fibres prior to cell seeding. Expression of osteogenic markers osteopontin, alkaline phosphatase (ALP), osteocalcin and type 1 collagen increased gradually with calcium phosphate deposition on GLU-NF microsheets. Results demonstrate that surface modification of aligned synthetic nanofibres with EEGGC peptide dramatically affects nucleation and growth of calcium phosphate crystals on the fibres leading to increased osteogenic differentiation of marrow stromal cells and mineralization.
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratories, Department of Chemical Engineering, University of South Carolina, Columbia, SC, USA.
authors.forename: Ozan
authors.initials: O
authors.lastname: Karaman
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratories, Department of Chemical Engineering, University of South Carolina, Columbia, SC, USA.
authors.forename: Ankur
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratories, Department of Chemical Engineering, University of South Carolina, Columbia, SC, USA.
authors.forename: Seyedsina
authors.initials: S
authors.lastname: Moeinzadeh
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratories, Department of Chemical Engineering, University of South Carolina, Columbia, SC, USA.
authors.forename: Xuezhong
authors.initials: X
authors.lastname: He
authors.affiliation: Department of Mechanical Engineering, University of South Carolina, Columbia, SC, USA.
authors.forename: Tong
authors.initials: T
authors.lastname: Cui
authors.affiliation: Biomimetic Materials and Tissue Engineering Laboratories, Department of Chemical Engineering, University of South Carolina, Columbia, SC, USA.
authors.forename: Esmaiel
authors.initials: E
authors.lastname: Jabbari
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D002130:Calcium Phosphates / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D048430:Cell Shape / Q000187:drug effects; D004247:DNA / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate; D005786:Gene Expression Regulation / Q000187:drug effects; D018698:Glutamic Acid / Q000494:pharmacology*; D019344:Lactic Acid / Q000494:pharmacology; D008297:Male; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D010455:Peptides / Q000494:pharmacology*; D011100:Polyglycolic Acid / Q000494:pharmacology; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D066244:Proton Magnetic Resonance Spectroscopy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017208:Rats, Wistar; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D013499:Surface Properties
chemical_list: D002130:Calcium Phosphates; D010455:Peptides; D012333:RNA, Messenger; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D018698:Glutamic Acid; D004247:DNA; C020243:calcium phosphate; D000469:Alkaline Phosphatase; D016650:Fluorescein-5-isothiocyanate
keywords: biomimetic mineralization; calcium phosphate nucleation; marrow stromal cells; nanofibre surface modification; osteogenesis; peptide conjugation