Papers by Author: M. Descamps

Abstract: The advantages of local antibiotic administration - high local levels with low systemic toxicity - are nowadays recognized as an efficient way for anti-infection therapies consecutive to the orthopaedic implant surgery. Aimed at assessing the feasibility of using Hydroxyapatite as drugdelivery carrier in addition to its well-known bone reconstruction bioactivity, a pure HA ceramic with specific internal pore size and porosities was under our investigation. The antibiotic release and antibacterial effect were determined by UV spectrophotometry and disk agar diffusion assays after impregnation with different antibiotics and their release in different solvents. No differences were found after the ATB impregnation under normal pressure or under vacuum conditions. The influences of impregnation time on the duration of the ATB release and on the antibacterial efficiency were more evident for Vancomycin than for Ciprofloxacin and Gentamycin. In all cases, the ATBs penetrated micro-porous and meso-porous HA samples and showed significantly stronger and longer anti-bacterial effects than dense HA samples. The ATBs releases in PBS were relatively slower and the antibacterial effectiveness subsequently prolonged with respect to those in human plasma. All tested HA samples with or without ATB impregnation exhibited very good biocompatibility as shown by cell proliferation tests. It revealed a promising perspective for further improving the antibacterial efficiency by other surface functionalization methods for achieving a controllable drug delivery with antibiotic loaded HA.

Abstract: Calcium phosphate compounds, in particular HA and β-TCP, are the principal synthetic materials used for bone substitutes. To assess the feasibility for further grafting of drug delivery systems, a pure HA was elaborated with specific internal material porosities and then tested on its biological effectiveness. The cell viability tests with L132 cells confirmed the excellent cytocompatibility of HA and the graphite powder. MC3T3-E1 osteoblasts were grown on HA conditioned with culture medium and FCS for 2h. All HA samples produced a higher proliferation and vitality rates than the TCPS controls; the micro-porous HA inducing the highest cell growth near 150%. The macro/meso-porous HA is easily colonized by MC3T3-E1 osteoblasts As to the cell morphology, no significant differences are observed between control cells and those grown on the HA samples. Cytochemical staining of osteoblasts revealed a well developed cytoskeleton with strong stress fibres oriented in the cells in their longitudinal direction. Labelling of the focal adhesion contacts with anti-vinculin showed a less developed adhesion process in the cells on the different HA substrates, which may explain the above mentioned increase of proliferation.