Biological assessment of uncoated and hydroxyapatitecoated ferum as biodegradable scaffold for hard tissue regeneration

Abstract

Pure iron (Fe) and its alloys have been recently emphasized as potential biodegradable metals due to their good mechanical properties that are close to those of stainless steel 316L. This research was focused more on the study of cell-material interaction and to analyze the effect of corrosion product on cell behavior by performing degradation study. In this study, samples were prepared by coating hydroxyapatite (HA) and hydroxyapatite/poly (s-Caprolactone) (HA/PCL) onto porous iron using dip coating method. Biosafety and biofunctionality of the sample were evaluated by using human skin fibroblast (HSF) and mesenchymal stem (MSC) cells. Analysis by Inductively Coupled Plasma- Mass Spectrometry (ICP-MS) revealed that concentration of ion Fe was decreased in the medium containing HAcoated Fe. However, the weight loss of the sample is high compared to pure porous iron and HA/PCL-coated Fe. A positive cell response to the Fe ions was revealed during the first 21 days of the cell toxicity study using indirect method. After 21 days the HSF cell viability decreased due to acidic eluates and the increase of Fe ions concentration that promoted the formation of the reactive oxygen intermediates (ROI). From the results obtained, it showed that the HSF and MSC cells exhibited higher viability when in contact with the Fe-HA and Fe-PCL/HA than with the Fe specimens. However, there is a significant decrease (p<0.05) of cells when cultured on three different samples after 3 days of incubation. HA-coated porous Fe also provides support for attachment of the cells. Observation under Scanning Electron Microscope (SEM) reveals that the filopodia of the mesenchymal stem cells preferred to develop onto irregular surface of HA-coated Fe. This study provided evidences of a good cell-material interaction on the porous Fe that may confirm the feasibility of using porous biodegradable ferum as hard tissue scaffolds.