Browsing by Author "Atorrasagasti, Garbiñe"
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Item Bioactivity of dexamethasone-releasing coatings on polymer/magnesium composites(2016-10-07) Bensiamar, Fátima; Olalde, Beatriz; Cifuentes, Sandra C.; Argarate, Nerea; Atorrasagasti, Garbiñe; González-Carrasco, José L.; García-Rey, Eduardo; Vilaboa, Nuria; Saldaña, Laura; BiomaterialesWe developed biodegradable polymeric coatings loaded with increasing amounts of dexamethasone on composites based on polylactic acid and Mg particles for bone repair. Incorporation of Mg particles into the polymeric matrix improves the compressive behaviour of the polymer. Mg-containing composites release Mg2+ ions into the culture medium and improve mesenchymal stem cell (MSC) viability, enhance their osteogenic potential and promote the release of angiogenic factors. Dexamethasone-loaded coatings deposited on composites delay Mg2+ ion dissolution while releasing controlled amounts of the drug, which are highly dependent on initial payload. Release kinetic of dexamethasone from the coatings exhibits a fast initial release of the drug followed by a slower secondary release. Bioactivity of the released dexamethasone was explored by monitoring dose-dependent responses of MSCs and macrophages. Biological effects exerted by the released drug are similar to those observed in cells treated with solutions of the glucocorticoid, indicating that the method employed for inclusion of dexamethasone into the coatings does not impair its bioactive behaviour. Culturing MSCs on dexamethasone-releasing coatings enhances extracellular matrix production and initial induction to osteogenic commitment as a function of drug payload. Dexamethasone incorporated into the coatings presents anti-inflammatory activity, as shown by the decrease in the production of cytokines and angiogenic factors by macrophages and MSCs. Deposition of dexamethasone-releasing coatings on polymer/Mg composites appears to be a promising approach to delay composite degradation at the early stage of implantation and may be useful to attenuate inflammation and adverse foreign body reactions.Item Biodegradable Bi-layered coating on polymeric orthopaedic implants for controlled release of drugs(2014-10-01) Argarate, Nerea; Olalde, Beatriz; Atorrasagasti, Garbiñe; Valero, Jesus; Carolina Cifuentes, Sandra; Benavente, Rosario; Lieblich, Marcela; Luis González-Carrasco, José; Biomateriales; Dirección GeneralA novel bone substitute incorporating biodegradable coatings on poly(d,l-lactide-co-lactide) (PLDL) implant has been developed. The polymer coatings were investigated as carrier of eugenol (EG) and dexamethasone (DM) which are suitable drugs to give antibacterial and anti-inflammatory function to the implant. The dip coating method was employed to coat the PLDL implant with poly(l-lactic acid) (PLLA) polymer. It has been observed that the thickness of the coating increased with the polymer concentration and the repetition of the dipping process showed an additive coating thickness compared to the single dipping. Moreover, it has been proved that a sequential drug release of EG and DM has been reached by incorporating the drugs onto each layer coating.Item Fabrication of ultrahigh-molecular-weight polyethylene porous implant for bone application(2020-09-01) Olalde, Beatriz; Ayerdi-Izquierdo, Ana; Fernández, Rubén; García-Urkia, Nerea; Atorrasagasti, Garbiñe; Bijelic, Goran; Biomateriales; MercadoPorous implants play a crucial role in allowing ingrowth of host connective tissue and thereby help in keeping the implant in its place. With the aim of mimicking the microstructure of natural extracellular matrix, ultrahigh-molecular-weight polyethylene (UHMWPE) porous samples with a desirable pore size distribution were developed by combining thermally induced phase separation and salt leaching techniques. The porous UHMWPE samples consisted of a nanofibrous UHMWPE matrix with a fibre diameter smaller than 500 nm, highly interconnected, with a controllable pore diameter from nanoscale to 300 μm. Moreover, a porous UHMWPE sample was also developed as a continuous and homogeneous coating onto the UHMWPE dense sample. The dense/porous UHMWPE sample supported human foetal osteoblast 1.19 cell line proliferation and differentiation, indicating the potential of porous UHMWPE with a desirable pore size distribution for bone application. An osseointegration model in the sheep revealed substantial bone formation within the pore layer at 12 weeks via SEM evaluation. Ingrown bone was more closely opposed to the pore wall when compared to the dense UHMWPE control. These results indicate that dense/porous UHMWPE could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopaedic application.Item Plasma polymerized silylated ciprofloxacin as an antibiotic coating(2011-07-22) Braceras, Inigo; Azpiroz, Patxi; Briz, Nerea; Fratila, Raluca M.; Oyarbide, Joseba; Ipiñazar, Enrique; Úlvarez, Noelia; Atorrasagasti, Garbiñe; Aizpurua, Jesus M.; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENO; SG; VALORIZACIÓN DE RESIDUOS; BiomaterialesLocally applied antibiotics under temporally controlled release present many advantages over systemic clinical treatments, e.g. efficiency and side effects. This can be achieved by a coating on top of the medical device, in which the antibiotic is stored. This study presents the use of plasma polymerization to produce such a coating using N,O-bis-tert- butyldimethylsilylated ciprofloxacin (silylciprofloxacin) as a precursor. Once exposed to physiological media, the outer layers of the coating release the antibiotic by a hydrolysis reaction. Thus, the plasma process parameters can control the speed of liberation through the coating polymerization. Besides, this study shows that the release products present antibiotic activity against a number of bacteria: E. coli, P. aeruginosa, and S. aureus. Ciprofloxacin release dynamics can be controlled by coating plasma polymerization parameters, allowing local controlled delivery of active antibiotic in physiologic conditions, and thus higher efficiency and lower side effects.Item "Plasma-click" based strategy for obtaining antibacterial surfaces on implants(2013-04) Braceras, Iñigo; Oyarbide, Joseba; Azpiroz, Patxi; Briz, Nerea; Ipiñazar, Enrique; Álvarez, Noelia; Atorrasagasti, Garbiñe; Fratila, Raluca M.; Aizpurua, Jesus M.; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENO; SG; VALORIZACIÓN DE RESIDUOS; BiomaterialesBiomaterials with surface antibacterial properties are promising components for medical implants that might provide an alternative to conventional systemic antibiotic treatments. Herein is reported a general method, based on plasma polymerization techniques, to promote the formation of "clickable surfaces" which can be conjugated with chemically modified antibiotics (e.g., azido-vancomycin) under very mild conditions. The procedure is comprised of three operations: (i) surface alkylcarboxylation with acrylic acid/CO 2 plasma, (ii) alkyne functionalization by condensation with propargylamine, and (iii) in situ Cu(I)-catalyzed alkyne-azide conjugation with azidovancomycin. The antibacterial activity of the resulting functionalized surfaces has been assessed against Staphylococcus epidermidis.