engleski

Synthesis and charaterization of hydroxyapatite- biodegradable polymer composite material

Scaffold materials for use in bone tissue engineering (BTE) that mimic both the structure and mechanical properties of the natural bone still represent a great challenge for researchers. Scaffold should provide a highly porous matrix with interconnected pores that enables the transport of nutrients, oxygen and metabolic waste products. Its surface properties must be suitable for cell adhesion, proliferation and differentiation. Also, the scaffold should be bioresorbable with a controllable degradation rate to match the replacement by new tissue. Additionally, the scaffold should possess sufficiently high mechanical properties such as stiffness, strength and toughness. Synthetic calcium phosphates, in particular hydroxyapatite (HAp, Ca10(PO4)6(OH)2), are the most commonly used ceramics in dentistry and bone repair due to their chemical similarity to the inorganic matrix of natural bone, excellent osteoconductivity and bioactivity. However, the major drawback of the HAp scaffolds is their poor mechanical properties. To overcome these disadvantages HAp has been combined with polymers that provide flexibility to the brittle system. Due to its biodegradability, biocompatibility and appropriate mechanical properties, poly(ε-caprolactone) (PCL) has been widely used to prepare composite HAp/PCL composite scaffolds for the use in bone tissue engineering. The present work reports on preparation of poly(ε- caprolactone)-coated highly porous hydroxyapatite (HAp/PCL) scaffolds derived from cuttlefish bone using vacuum impregnation technique. The results showed that PCL-coated HAp scaffold resulted in material with improved mechanical properties that keeps the original interconnected porous structure indispensable for tissue growth and vascularization. The obtained compressive strength (0.88 MPa) and the elastic modulus (15.5 MPa) of the composite scaffolds are within the lower range of properties reported for human trabecular bones. Thermogravimetric analysis showed that the HAp/PCL composite scaffolds contain (48.7 ± 0.1) wt. % of PCL. The in vitro mineralization of calcium phosphate that transforms into the bone-like apatite was observed on the HAp/PCL composite scaffold after 28 days of immersion in Hank's balanced salt solution. Furthermore, preliminary in vitro biological evaluation of the scaffolds was carried out using pre-osteoblastic MC3T3-E1 cell line. The results of the MTS viability test corroborated the direct observation under the microscope showing that and HAp/PCL scaffolds do not exert any cytotoxic effect on MC3T3-E1 cells. The proliferative behavior of the cells on the HAp/PCL composite scaffolds was confirmed by increase in cellular DNA production with culture time. The cell proliferation was followed by the expression of the early stage differentiation markers, alkaline phosphatase and type I collagen, respectively. Finally, the prepared highly porous PCL-coated hydroxyapatite scaffold derived from cuttlefish bone could be a suitable candidate for use in bone regenerative medicine.

poly(ε-caprolactone); hydroxyapatite; scaffold; tissue engineering

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