The investigation of desired product properties of polycaprolactone-hydroxy apatite composites for tissue engineering applications

Abstract

Biomaterials are used to perform or support the function of living tissues and contact with body fluids [1-3]. For temporary implants, biodegradation products of scaffolds have to be compatible with the body, and biodegradation time must be sufficient for regeneration of the tissue [4,5]. The aim of this study is to produce composites with improved product properties by using Polycaprolactone (PCL, hydrophobic and long biodegradation time) and Hydroxy apatite (HA, weak mechanical properties) that are not sufficient alone. Oleic Acid (OA) and Glycerol Monooleate (GMO) as organic additives were selected to provide a homogeneous distribution of the ceramic material in the polymer matrix. Desired product properties of prepared composites using different concentrations of these inorganic and organic additives and affecting parameters on these product properties were investigated for tissue engineering. Biocomposite materials were prepared with solvent casting technique using dichloromethane as the solvent. Salt was used as the porosifier. FTIR and EDX analyses for chemical characterization, tensile and compressive tests for determining mechanical properties, SEM analyses for determining surface properties, and BET analyses for pore sizes, total surface areas and total pore volumes of scaffolds were performed. Materials were kept in 5 times concentrated simulated body fluid (SBF) at 37°C for 2 days to determine the bioactivity. FTIR, EDX, and SEM analyses were performed again for characterization after SBF treatment. MTT test for determining toxicity and cell proliferation experiments for testing tissue regeneration will be performed. Composite materials which have micro and macro pore distribution are required for tissue engineering applications. Optical microscope images showed that prepared scaffolds had porous structure. Neat PCL is biocompatible with human body because of the increment of Ca/P ratio after SBF from zero to 2. Scaffolds that contain 3 wt% HA are more compatible than scaffolds that contain 20 wt% HA, and OA is more effective than GMO to form a new HA layer. Obtained results show that the composites are suitable for soft tissue applications.

Keywords

• Polycaprolactone, hydroxy apatite, tissue engineering, scaffold, simulated body fluid, bioactivity

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