title: Effect of organic acids on calcium phosphate nucleation and osteogenic differentiation of human mesenchymal stem cells on peptide functionalized nanofibers.
abstract: Carboxylate-rich organic acids play an important role in controlling the growth of apatite crystals and the extent of mineralization in the natural bone. The objective of this work was to investigate the effect of organic acids on calcium phosphate (CaP) nucleation on nanofiber microsheets functionalized with a glutamic acid peptide and osteogenic differentiation of human mesenchymal stem cells (hMSCs) seeded on the CaP-nucleated microsheets. High molecular weight poly(dl-lactide) (DL-PLA) was mixed with low molecular weight L-PLA conjugated with Glu-Glu-Gly-Gly-Cys peptide, and the mixture was electrospun to generate aligned nanofiber microsheets. The nanofiber microsheets were incubated in a modified simulated body fluid (mSBF) supplemented with different organic acids for nucleation and growth of CaP crystals on the nanofibers. Organic acids included citric acid (CA), hydroxycitric acid (HCA), tartaric acid (TART), malic acid (MA), ascorbic acid (AsA), and salicylic acid (SalA). HCA microsheets had the highest CaP content at 240 ± 10% followed by TART and CA with 225 ± 8% and 225 ± 10%, respectively. The Ca/P ratio and percent crystallinity of the nucleated CaP in TART microsheets was closest to that of stoichiometric hydroxyapatite. The extent of CaP nucleation and growth on the nanofiber microsheets depended on the acidic strength and number of hydrogen-bonding hydroxyl groups of the organic acids. Compressive modulus and degradation of the CaP nucleated microsheets were related to percent crystallinity and CaP content. Osteogenic differentiation of hMSCs seeded on the microsheets and cultured in osteogenic medium increased only for those microsheets nucleated with CaP by incubation in CA or AsA-supplemented mSBF. Further, only CA microsheets stimulated bone nodule formation by the seeded hMSCs.
authors: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States.
authors: Danial
authors: D
authors: Barati
authors: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States.
authors: Joshua D
authors: JD
authors: Walters
authors: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States.
authors: Seyed Ramin Pajoum
authors: SR
authors: Shariati
authors: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States.
authors: Seyedsina
authors: S
authors: Moeinzadeh
authors: Biomimetic Materials and Tissue Engineering Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States.
authors: Esmaiel
authors: E
authors: Jabbari
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D002130:Calcium Phosphates / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002951:Citrates / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology; D006801:Humans; D008293:Malates / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects*; D057139:Nanofibers / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry*; D020156:Salicylic Acid / Q000494:pharmacology; D013644:Tartrates / Q000494:pharmacology
chemical_list: D002130:Calcium Phosphates; D002951:Citrates; D008293:Malates; D009842:Oligopeptides; D013644:Tartrates; D019343:Citric Acid; C030298:malic acid; C007999:hydroxycitric acid; C020243:calcium phosphate; D020156:Salicylic Acid; D001205:Ascorbic Acid; C029768:tartaric acid