Development of clinoptilolite/poly ε-caprolactone -polyethylene glycol - poly ε-caprolactone triblock copolymer based scaffolds for bone tissue engineering

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2016
Pazarçeviren, Ahmet Engin
Bone tissue engineering mainly depends on the feasible substitutes with ability to regenerate damaged bone tissue. One of the applications in which bone tissue engineering mainly focuses on is the production of bone tissue scaffolds. These scaffolds are expected to be biocompatible, highly interconnective and porous to provide a niche for colonizing bone cells. In addition, bone tissue scaffolds should be mechanically strong enough to accommodate compression. Scaffolds should also be biodegradable to encourage bone cell growth and mineralization in order to accomplish bone regeneration at the defect site. Considering the aforementioned, poly (caprolactone) - poly (ethylene glycol) - poly (caprolactone) (PCL-PEGPCL) triblock copolymer composite scaffolds with clinoptilolite earth mineral were fabricated to provide mechanical strength as well as stable environment for bone tissue growth at the defect site. Clinoptilolite, a natural zeolite, was selected as a bioactive ceramic component for improving tmechanical and biological properties of PCL-PEG-PCL based scaffolds. Highly porous clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (CLN/PCEC) composite scaffolds with different clinoptilolite contents (10% and 20%) were fabricated with reproducible solvent free powder compression/particulate leaching technique. The scaffolds had interconnective pores and the porosity ranged between 55% to 76%. vi CLN/PCEC scaffolds showed negligible degradation within 8 weeks and displayed less water uptake and higher bioactivity than PCEC scaffolds. Presence of clinoptilolite improved the mechanical properties. Highest compressive strength (5.60 MPa) and modulus (114.84 MPa) were reached with scaffold group containing 20% CLN. In vitro protein adsorption capacity of these scaffolds (0.95 mg protein/g scaffold) was also higher for CLN/PCEC scaffolds. They also had higher osteoinductivity in terms of enhanced ALP, OSP activities and intracellular calcium deposition of seeded cells. Stoichiometric apatite deposition (Ca/P=1.686) was observed during cell proliferation analysis with human fetal osteoblasts cells. Thus, it can be suggested that CLN/PCEC composite scaffolds could be promising carriers for enhancement of bone regeneration in bone tissue engineering applications.

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Citation Formats
A. E. Pazarçeviren, “Development of clinoptilolite/poly ε-caprolactone -polyethylene glycol - poly ε-caprolactone triblock copolymer based scaffolds for bone tissue engineering,” M.S. - Master of Science, Middle East Technical University, 2016.