Dielectric Properties of PLA-PGA-Chitosan – Hydroxyapatite composites

Electrochemical studies applicable to osteosynthesis materials have been conducted to characterize the interface created between the implant surface and the cells, in the complex processes involved in the mechanisms of interaction of the medical device and the surrounding tissue. An electrochemical technique used is electrochemical impedance spectroscopy (EIS), from which it is possible to calculate the permittivity and conductivity of the system under study in a frequency range, which describe the dielectric response of composites or coatings. These parameters (permittivity and conductivity) provide information on the ability to allow movement of the charge carriers and a measure of the polarizability. In this paper a dielectric spectrum of a coating of polylactic acid (PLA), polyglycolic acid (PGA), chitosan and hydroxyapatite (HAp) on discs Ti6Al4V using the EIS technique in a culture medium with human osteosarcoma cells HOS was obtained. According to the obtained spectrum it was evident the dispersions alpha (α) and beta (β) showing the integrity of the biological tissue, related to ion exchange and polarization of the cell membrane. It was found that the best concentration of hydroxyapatite and chitosan interaction osteoblast cell surface modified Ti6Al4V was 15% w/w and7% w/w Hap and Chitosan respectively in a polymer matrix of PLA-PGA. The surface morphology was assessed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).