Vascular PET Prostheses Surface Modification with Cyclodextrin Coating: Development of a New Drug Delivery System

AbstractPurposeCyclodextrins (CDs) are torus shaped cyclic oligosaccharides with a hydrophobic internal cavity and a hydrophilic external surface. We performed and analysed an antibiotic binding on Dacron (polyethyleneterephtalate, PET) vascular grafts, previously coated with CDs based polymers.MethodsThe CDs coating process was based on the pad-dry-cure method patented in our laboratory. The Dacron prostheses were immersed into a solution containing a polycarboxylic acid, a cyclodextrin and a catalyst, and placed into a thermofixation oven before impregnation with an antibiotic solution (Vancomycin). Biocompatibility tests were performed with L132 human epithelial cells. The antibiotic release in an aqueous medium was assessed by batch type experiments using UV spectroscopy.ResultsViability tests confirmed that the CDs polymers coating the Dacron fibers were not toxic towards L132 cell. Cell proliferation was similar on coated and uncoated grafts.A linear release of Vancomycin was observed over 50 days.ConclusionOur results demonstrate the feasibility of coating CDs onto vascular Dacron grafts. Biological tests show no toxicity of the different cyclodextrins coated. A linear release of antibiotics was depicted over 50 days, demonstrating that cyclodextrin grafting was an efficient drug delivery system

Improvement of biological response of YAG laser irradiated polyethylene.

International audiencePE was manufd. by thermocompression of PE micro beads. This end product was then irradiated by a 1064 nm YAG laser. In the first part the phys. characteristics of untreated and laser irradiated samples are compared. DSC revealed a max. of crystallinity of PE, and YAG laser treatment did not influence the crystallinity. Weattability between PE and the laser irradiated PE (Li-PE) was similar with about 37 mJ cm-2. Differences appeared, however, as to the surface profile and the surface compn.: increase of the roughness of 0.20 mm for PE vs. 0.29 mm for Li-PE; XPS reveals that traces of stripping agents on PE mostly disappeared after surface cleaning by YAG laser treatment. Biol. tests confirmed the non-toxicity of polyethylene powder and revealed a 4-fold proliferation increase and a 2-fold vitality stimulation of L132 cells cultured on Li-PE with respect to those grown on untreated PE. No differences were obsd. as to the morphol. and cell adhesion between the two samples. The modified surface morphol. and surface compn. may explain the improved biol. reactions

Physico-chemical and biological evaluation of excimer laser irradiated polyethylene terephthalate (pet) surfaces.

The aim of this work was to investigate the consequences of excimer laser irradn. on the physico-chem. and biol. properties of polyethylene terephthalate (PET) films, currently used for medical devices. Three PET films from different origins were studied in the present work, chosen with respect to their chem. and phys. properties, which are of high importance for ulterior medical application as vascular prostheses. Multiple assays were carried out to characterize the phys. and chem. effects of the laser irradn.: surface morphol. tests (light microscopy, Dektak profilometer and confocal laser scanning microscopy) showed the strong transformation of the surface with the laser treatment. Contact angle measurements revealed a significant increase of the surface energy for each PET depending on the applied fluency. Finally XPS characterization of the surface demonstrated the appearance of new chem. species favorable for cell attachment. This aspect had to be strongly considered regarding to the multiple biol. effects of laser irradiated surfaces on living cells. Different cell culture expts. were carried out with L132 human epithelial cells after 6-days culture: proliferation and vitality rate, cell adhesion and cell morphol. Results clearly revealed that laser treatment improved cell proliferation (up to 140% with respect to controls), vitality (10% higher than controls), morphol. and adhesion kinetics (more than 16% of control). A significant correlation (R2=0.906) was also established on one PET between the fluencies of laser treatment and the cellular response. These results emphasized high importance of the choice of the PET material for a medical application: only one of the three considered PET films showed really improved cellular response

C38 - Évaluation in vitro de l'activité antibactérienne d'un pansement chargé d'extraits de plantes

Introduction : Les plaies infectées constituent un problème de santé publique du fait qu’elles peuvent prolonger la durée d’une hospitalisation. Les pansements utilisés dans leurs prises en charge contiennent souvent des antibactériens comme l’ion argent. Cette étude, dans le cadre de la valorisation des plantes Sénégalaises utilise comme actif antibactérien un extrait de noyau de mangue et d’avocat sur un support textile PET enduit d’un film plastique à base d’amidon. Matériel et Méthodes : Les concentrations minimales inhibitrices d'extraits de plantes sur les souches testées ont été réalisées dans des boîtes de Pétri. Un mélange des extraits actifs à part égale d'extrait d'éther de pétrole de noyau d'avocat (Persea americana) et d'extrait méthanolique de noyau de mangue (Mangifera indica) a ensuite été testé. Ce mélange a été incorporé dans un pansement constitué d'un textile et d'un film plastique à base d’amidon contenant de la carboxyméthylcellulose et du polymère de bêta-cyclodextrine comme absorbant. Des tests Kirby-Bauer et kill time ont finalement été réalisés sur le pansement contenant le mélange d'extraits. Résultats/discussion : Le mélange avocat/mangue 1:1 incorporé dans le pansement a induit une réduction logarithmique de 3,5 log de Staphylococcus aureus (ATCC 6538). Cependant, en raison d'une activité plus faible observée contre les bactéries à Gram négatif (Pseudomonas aeruginosa) et les champignons (Candida albicans), le pansement a donc pu être indiqué sur des plaies non surinfectées (absence de Pseudomonas). En ce qui concerne la capacité d'absorption (1,72 g/100 cm2), ce type de pansement est un pansement à absorption moyenne et pourrait être recommandé pour les plaies aiguës et chroniques à faible activité exsudative au stade bourgeonnant. Nos résultats démontrent l'efficacité du pansement textile avec des extraits de plantes