scholarly journals Bioreactor-based bone tissue engineering: The influence of dynamic flow on osteoblast phenotypic expression and matrix mineralization

2004 ◽  
Vol 101 (31) ◽  
pp. 11203-11208 ◽  
Author(s):  
X. Yu ◽  
E. A. Botchwey ◽  
E. M. Levine ◽  
S. R. Pollack ◽  
C. T. Laurencin
2017 ◽  
Vol 26 (9) ◽  
pp. 1496-1504 ◽  
Author(s):  
Denis Dufrane

Bone nonunion is a pathological condition in which all bone healing processes have stopped, resulting in abnormal mobility between 2 bone segments. The incidence of bone-related injuries will increase in an aging population, leading to such injuries reaching epidemic proportions. Tissue engineering and cell therapy using mesenchymal stem cells (MSCs) have raised the possibility of implanting living tissue for bone reconstruction. Bone marrow was first proposed as the source of stem cells for bone regeneration. However, as the quantity of MSCs in the bone marrow decreases, the capacity of osteogenic differentiation of bone marrow stem cells is also impaired by the donor’s age in terms of reduced MSC replicative capacity; an increased number of apoptotic cells; formation of colonies positive for alkaline phosphatase; and decreases in the availability, growth potential, and temporal mobilization of MSCs for bone formation in case of fracture. Adipose-derived stem cells (ASCs) demonstrate several advantages over those from bone marrow, including a less invasive harvesting procedure, a higher number of stem cell progenitors from an equivalent amount of tissue harvested, increased proliferation and differentiation capacities, and better angiogenic and osteogenic properties in vivo. Subcutaneous native adipose tissue was not affected by the donor’s age in terms of cellular senescence and yield of ASC isolation. In addition, a constant mRNA level of osteocalcin and alkaline phosphatase with a similar level of matrix mineralization of ASCs remained unaffected by donor age after osteogenic differentiation. The secretome of ASCs was also unaffected by age when aiming to promote angiogenesis by vascular endothelial growth factor (VEGF) release in hypoxic conditions. Therefore, the use of adipose cells for bone tissue engineering is not limited by the donor’s age from the isolation of stem cells up to the manufacturing of a complex osteogenic graft.


2016 ◽  
Vol 19 (2) ◽  
pp. 93-100
Author(s):  
Lalita El Milla

Scaffolds is three dimensional structure that serves as a framework for bone growth. Natural materials are often used in synthesis of bone tissue engineering scaffolds with respect to compliance with the content of the human body. Among the materials used to make scafffold was hydroxyapatite, alginate and chitosan. Hydroxyapatite powder obtained by mixing phosphoric acid and calcium hydroxide, alginate powders extracted from brown algae and chitosan powder acetylated from crab. The purpose of this study was to examine the functional groups of hydroxyapatite, alginate and chitosan. The method used in this study was laboratory experimental using Fourier Transform Infrared (FTIR) spectroscopy for hydroxyapatite, alginate and chitosan powders. The results indicated the presence of functional groups PO43-, O-H and CO32- in hydroxyapatite. In alginate there were O-H, C=O, COOH and C-O-C functional groups, whereas in chitosan there were O-H, N-H, C=O, C-N, and C-O-C. It was concluded that the third material containing functional groups as found in humans that correspond to the scaffolds material in bone tissue engineering.


Author(s):  
Mariane Beatriz Sordi ◽  
Ariadne Cristiane Cabral da Cruz ◽  
Águedo Aragones ◽  
Mabel Mariela Rodríguez Cordeiro ◽  
Ricardo de Souza Magini

The aim of this study was to synthesize, characterize, and evaluate degradation and biocompatibility of poly(lactic-co-glycolic acid) + hydroxyapatite / β-tricalcium phosphate (PLGA+HA/βTCP) scaffolds incorporating simvastatin (SIM) to verify if this biomaterial might be promising for bone tissue engineering. Samples were obtained by the solvent evaporation technique. Biphasic ceramic particles (70% HA, 30% βTCP) were added to PLGA in a ratio of 1:1. Samples with SIM received 1% (m:m) of this medication. Scaffolds were synthesized in a cylindric-shape and sterilized by ethylene oxide. For degradation analysis, samples were immersed in PBS at 37 °C under constant stirring for 7, 14, 21, and 28 days. Non-degraded samples were taken as reference. Mass variation, scanning electron microscopy, porosity analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry were performed to evaluate physico-chemical properties. Wettability and cytotoxicity tests were conducted to evaluate the biocompatibility. Microscopic images revealed the presence of macro, meso, and micropores in the polymer structure with HA/βTCP particles homogeneously dispersed. Chemical and thermal analyses presented very similar results for both PLGA+HA/βTCP and PLGA+HA/βTCP+SIM. The incorporation of simvastatin improved the hydrophilicity of scaffolds. Additionally, PLGA+HA/βTCP and PLGA+HA/βTCP+SIM scaffolds were biocompatible for osteoblasts and mesenchymal stem cells. In summary, PLGA+HA/βTCP scaffolds incorporating simvastatin presented adequate structural, chemical, thermal, and biological properties for bone tissue engineering.


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