title: Effective combination of aligned nanocomposite nanofibers and human unrestricted somatic stem cells for bone tissue engineering.
abstract: OBJECTIVE
  Bioartificial bone tissue engineering is an increasingly popular technique to solve bone defect challenges. This study aimed to investigate the interactions between matrix composition and appropriate cell type, focusing on hydroxyapatite (HA), to achieve a more effective combination for bone regeneration.
  
  
  METHODS
  Human unrestricted somatic stem cells (USSCs) were isolated from placental cord blood. The cellular and molecular events during the osteo-induction of USSCs were evaluated for 21 d under the following conditions: (1) in basal culture, (2) supplemented with hydroxyapatite nanoparticle (nHA) suspension, and (3) seeded on electrospun aligned nanofibrous poly-ɛ-caprolactone/poly-L-lactic acid/nHA (PCL/PLLA/nHA) scaffolds. The scaffolds were characterized using scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR) and tensile test.
  
  
  RESULTS
  Maintenance of USSCs for 21 d in basal or osteogenic culture resulted in significant increase in osteoblast differentiation. With nHA suspension, even soluble osteo-inductive additives were ineffective, probably due to induced apoptosis of the cells. In contrast to the hindrance of proliferation by nHA suspension, the scaffolds improved cell growth. The scaffolds mimic the nanostructure of natural bone matrix with the combination of PLLA/PCL (organic phase) and HA (inorganic phase) offering a favorable surface topography, which was demonstrated to possess suitable properties for supporting USSCs. Quantitative measurement of osteogenic markers, enzymatic activity and mineralization indicated that the scaffolds did not disturb, but enhanced the osteogenic potential of USSCs. Moreover, the alignment of the fibers led to cell orientation during cell growth.
  
  
  CONCLUSIONS
  The results demonstrated the synergism of PCL/PLLA/nHA nanofibrous scaffolds and USSCs in the augmentation of osteogenic differentiation. Thus, nHA grafted into PCL/PLLA scaffolds can be a suitable choice for bone tissue regeneration.
authors.affiliation: Department of Biotechnology, College of Science, University of Tehran, Iran.
authors.forename: Behnaz
authors.initials: B
authors.lastname: Bakhshandeh
authors.forename: Masoud
authors.initials: M
authors.lastname: Soleimani
authors.forename: Nasser
authors.initials: N
authors.lastname: Ghaemi
authors.forename: Iman
authors.initials: I
authors.lastname: Shabani
mesh_terms: D017209:Apoptosis; D001672:Biocompatible Materials / Q000737:chemistry; D001861:Bone Regeneration; D002454:Cell Differentiation; D049109:Cell Proliferation; D017886:Durapatite / Q000737:chemistry; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry; D057139:Nanofibers / Q000737:chemistry*; D010006:Osteoblasts / Q000378:metabolism; D011091:Polyesters / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013234:Stem Cells / Q000378:metabolism*; D013718:Tensile Strength; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; C016240:polycaprolactone; D019344:Lactic Acid; C033616:poly(lactide); D017886:Durapatite