Electrophoretic deposition of carbon nanotubes and bioactive glass particles for bioactive composite coatings

The production of bioactive coatings consisting of 45S5 Bioglass (R) and mutli-walled carbon nanotubes (CNTs) by electrophoretic deposition (EPD) was investigated. In addition to pure Bioglass (R) coatings, the co-deposition and sequential deposition of Bioglass (R) particles (size <5 mu m) and CNTs on stainless steel substrates were carried out in order to fabricate bioactive, nanostructured composite layers. The optimal experimental conditions were determined using well-dispersed suspensions by means of a trial-and-error approach by varying the relevant EPD parameters: applied voltage and deposition time. SEM images demonstrated the successful fabrication of Bioglass (R)/CNT composites by revealing their morphology and topography. The co-deposition of Bioglass (R) particles and CNTs resulted in homogenous and dense coatings exhibiting the presence of well-dispersed CNTs placed in-between micron-sized Bioglass (R) particles. This network of high-strength CNTs embedded in the glass layer could act as reinforcing element leading to higher mechanical stability of the coatings. The coatings obtained by sequential deposition offered a two-dimensional nanostructured fibrous mesh of CNTs covering the Bioglass (R) layer thus providing a controlled (ordered) nano-topographical surface. This surface nanostructure has the potential to promote the attachment and growth of osteoblast cells and to benefit the formation of bone-like nanosized hydroxyapaptite crystals in contact with body fluids. (C) 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.