262 research outputs found

    Antimicrobial peptides: Powerful biorecognition elements to detect bacteria in biosensing technologies

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    Bacterial infections represent a serious threat in modern medicine. In particular, biofilm treatment in clinical settings is challenging, as biofilms are very resistant to conventional antibiotic therapy and may spread infecting other tissues. To address this problem, biosensing technologies are emerging as a powerful solution to detect and identify bacterial pathogens at the very early stages of the infection, thus allowing rapid and effective treatments before biofilms are formed. Biosensors typically consist of two main parts, a biorecognition moiety that interacts with the target (i.e., bacteria) and a platform that transduces such interaction into a measurable signal. This review will focus on the development of impedimetric biosensors using antimicrobial peptides (AMPs) as biorecognition elements. AMPs belong to the innate immune system of living organisms and are very effective in interacting with bacterial membranes. They offer unique advantages compared to other classical bioreceptor molecules such as enzymes or antibodies. Moreover, impedance-based sensors allow the development of label-free, rapid, sensitive, specific and cost-effective sensing platforms. In summary, AMPs and impedimetric transducers combine excellent properties to produce robust biosensors for the early detection of bacterial infectionsPeer ReviewedPostprint (published version

    Procesos de adiestramiento de alambres ortodóncicos con memoria de forma

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    Los alambres de ortodoncia de níquel-titanio son suministrados por los diferentes fabricantes con forma de arco estándar. Los procesos de adiestramiento o de "eduación" permiten cambiar las formas del arco dental del alambre. Esta propiedad permitirá que el material a una temperatura tenga una forma y que a una temperatura menor recuerde otra forma diferente. Este doblre efecto memoria de forma proporciona al clínico una mayor versatilidad de los alambres NiTi en el tratamiento ortodóncico.Peer Reviewe

    Aplicación y caracterización físico-química de varios tratamientos superficiales realizados al acero inoxidable 316 L para aplicacions biomédicas

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    La biocompatibilidad de los metales utilizados en implantolog√≠a est√° √≠ntimamente relacionada con las caracter√≠sticas superficiales de los implantes tanto desde un punto de vista qu√≠mico como topogr√°fico. El objetivo de este trabajo es aplicar varios tratamientos superficiales al acero inoxidable 316 L y caracterizar, posteriormente, la superficie f√≠sico-qu√≠micamente. La superficie pulida de varios discos de acero 316 L fue tratada mediante los procesos de: granallado, variando el tama√Īo y la naturaleza de la part√≠culas proyectadas, y anodizado electroqu√≠mico. Con el fin de caracterizar las superficies obtenidas con cada tratamiento se observ√≥ la morfolog√≠a superficial mediante Microscopia Electr√≥nica de Barrido e Inteferometr√≠a √ďptica y se evalu√≥ el efecto de dichos tratamientos en la resistencia a la corrosi√≥n y en la liberaci√≥n de iones n√≠quel y cromo mediante ensayos in vitro. Los resultados revelaron que el tratamiento de granallado permite obtener un amplio rango de rugosidades incrementando el √°rea real hasta un 54% pero disminuyendo ligeramente la resistencia a la corrosi√≥n del material. El proceso de anodizado pr√°cticamente no tuvo efectos en la topograf√≠a sin embargo redujo considerablemente la resistencia a la corrosi√≥n del metal. Todos los tratamientos estudiados disminuyeron ligeramente la liberaci√≥n de iones cromo y n√≠quel

    Aplicación y caracterización físico-química de varios tratamientos superficiales realizados al acero inoxidable 316L para aplicaciones biomédicas

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    La biocompatibilidad de los metales utilizados en implantolog√≠a est√° √≠ntimamente relacionada con las caracter√≠sticas superficiales de los implantes tanto desde un punto de vista qu√≠mico como topogr√°fico. El objetivo de este trabajo es aplicar varios tratamientos superficiales al acero inoxidable 316 L y caracterizar, posteriormente, la superficie f√≠sico-qu√≠micamente. La superficie pulida de varios discos de acero 316 L fue tratada mediante los procesos de: granallado, variando el tama√Īo y la naturaleza de la part√≠culas proyectadas, y anodizado electroqu√≠mico. Con el fin de caracterizar las superficies obtenidas con cada tratamiento se observ√≥ la morfolog√≠a superficial mediante Microscopia Electr√≥nica de Barrido e Inteferometr√≠a √ďptica y se evalu√≥ el efecto de dichos tratamientos en la resistencia a la corrosi√≥n y en la liberaci√≥n de iones n√≠quel y cromo mediante ensayos in vitro. Los resultados revelaron que el tratamiento de granallado permite obtener un amplio rango de rugosidades incrementando el √°rea real hasta un 54% pero disminuyendo ligeramente la resistencia a la corrosi√≥n del material. El proceso de anodizado pr√°cticamente no tuvo efectos en la topograf√≠a sin embargo redujo considerablemente la resistencia a la corrosi√≥n del metal. Todos los tratamientos estudiados disminuyeron ligeramente la liberaci√≥n de iones cromo y n√≠quel

    Impedimetric antimicrobial peptide-based sensor for the early detection of periodontopathogenic bacteria

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    Peri-implantitis, an inflammation caused by biofilm formation, constitutes a major cause of implant failure in dentistry. Thus, the detection of bacteria at the early steps of biofilm growth represents a powerful strategy to prevent implant-related infections. In this regard, antimicrobial peptides (AMPs) can be used as effective biological recognition elements to selectively detect the presence of bacteria. Thus, the aim of the present study was to combine the use of miniaturized and integrated impedimetric transducers and AMPs to obtain biosensors with high sensitivity to monitor bacterial colonization. Streptococcus sanguinis, which is one of the most prevalent strains in the onset of periodontal diseases, was used as a model of oral bacteria. To this end, a potent AMP derived from human lactoferrin was synthesized and covalently immobilized on interdigitated electrode arrays (IDEA). X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) were employed to optimize and characterize the method of immobilization. Noteworthy, the interaction of Streptococcus sanguinis with AMP-coated sensors provoked significant changes in the impedance spectra, which were univocally associated with the presence of bacteria, proving the feasibility of our method. In this regard, the developed biosensor permits to detect the presence of bacteria at concentrations starting from 101 colony forming units (CFU) mL-1 in KCl and from 102 CFU mL-1 in artificial saliva. Moreover, the system was devoid of cytotoxicity for human fibroblasts. These results indicate that the proposed approach can be effective in the detection of initial stages of biofilm formation, and may be useful in the early prevention and treatment of peri-implantitisPeer ReviewedPostprint (author's final draft

    Cerámicas de circona para aplicaciones biomédicas

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    Se tratan los aspectos mas significativos de distintos biomateriales empleados para la sustitución del tejido óseo pero haciendo énfasis en las cerámicas de óxido de zirconio (circonas). Se destacan las características de las cerámicas de circona que lo convierten en un material muy atractivo por sus excelentes propiedades mecánicas, en particular su elevada tenacidad a la fractura relacionada con la transformación martensítica que se produce cuando el material es sometido a un esfuerzo mecánico. Por esta razón se ha empleado como biomaterial en la fabricación de diversos componentes de prótesis articulares fundamentalmente en las prótesis de cadera. También se han empleado con relativo éxito en otras aplicaciones clínicas como la odontología y la cirugía máxilo-facial. En la actualidad, se trabaja en conferirle bioactividad a las cerámicas de circona para facilitar su unión al tejido óseo sin afectar sus buenas propiedades mecánicas.Peer Reviewe

    Oxidación superficial de aleaciones de NiTi para la mejora de la biocompatibilidad

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    Se han estudiado diferentes tratamientos superficiales con el fin de obtener una capa de TiO2 con una m√≠nima concentraci√≥n de Ni en la superficie de aleaciones de NiTi 50/50 con memoria de forma: pulido espejo, autoclave, electropulido, oxidaci√≥n en un ba√Īo de agua hirviendo y oxidaci√≥n t√©rmica en atm√≥sfera controlada de aire. Se analizaron las superficies de las muestras mediante XPS. El tratamiento de oxidaci√≥n t√©rmica es el que da el ratio Ti/Ni m√°s alto, la menor cantidad de Ni en superficie y tambi√©n el mayor espesor de √≥xido. Se comprob√≥ mediante un experimento de liberaci√≥n de iones que el √≥xido formado por este proceso de oxidaci√≥n hace disminuir la liberaci√≥n de iones Ni al medio fisiol√≥gico respecto a la superficie no tratada. Se hicieron estudios de cultivos celulares de osteoblastos de l√≠nea MG63 sobre superficies no tratadas y tratadas t√©rmicamente de NiTi. Los resultados de proliferaci√≥n muestran que, para los d√≠as 3, 6 y 9 no existen diferencias estad√≠sticamente significativas entre los materiales. Sin embargo, despu√©s de 48h de estimulaci√≥n para la diferenciaci√≥n, las c√©lulas cultivadas sobre las superficies tratadas t√©rmicamente demuestran una mayor actividad de la fosfatasa alcalina y mayores niveles de osteocalcina.Various surface treatments have been studied in order to find the most appropriate in forming a TiO2 with a low Ni content on the surface of equiatomic NiTi alloys. Sample surfaces have been analyzed by XPS. Thermal oxidation treatment in an air-controlled atmosphere leads to the highest Ti/Ni ratio, to the lowest Ni surface concentration and to the thickest oxide layer. It has been shown by the results of ion release experiment that the oxide formed by this oxidation process allows to decrease Ni release into exterior medium comparing with non-treated surfaces. Cell cultures of MG63 osteoblast-like cells have been carried out. The proliferation study shows that from day 3 to day 9 there is no statistically significant differences between negative control, non-treated and thermally oxidized surfaces. After 48h of stimulation for differentiation, MG63 cells on thermally oxidized surfaces show higher phosphatase alkaline activity and osteocalcin level

    Blocking methods to prevent non-specific adhesion of mesenchymal stem cells to titanium and evaluate the efficiency of surface functionalization: albumin vs poly(ethylene glycol) coating

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    Premio SIBB 2014Surface modification of biocompatible materials with biologically-active molecules is a well-known strategy to enhance the osteointegration of implantable devices. In order to evaluate the efficiency of these treatments, an in vitro study of cell behavior on the modified surface is usually carried out. A key point to evaluate the efficacy of this strategy is to avoid non specific protein adsorption by creating a non-fouling background. This blocking step ensures that the observed response of cells can be exclusively ascribed to the modification treatment applied. Several techniques are available to create this neutral background. Thus, the aim of this study is to compare two different blocking methods, namely adsorption of albumin from bovine serum (BSA) and grafting of small polyethylene glycol (PEG) chains to titanium, which is the gold standard metal for orthopedics and dentistry. To this end, titanium surfaces were coated with a recently synthesized cell adhesive peptide-based molecule and subjected to a blocking procedure with either BSA or PEG.  Non-functionalized titanium samples were also blocked and used as controls. The biological response of human mesenchymal stem cells was evaluated by measuring the number of attached cells and studying the degree of cell spreading on the substrate. Both aspects of cell behavior are not affected significantly by the blocking method: cells adhere and spread significantly more on the functionalized samples, regardless of the blocking method used. This confirms that the surface feature that defines cell response is the presence/absence of the biomolecule, and not the anti-fouling layer. These results, together with the reduction of variability of results observed in presence of a blocking layer, demonstrate the efficacy and necessity of blocking the surface. PEG grafting is demonstrated as effective as BSA coating in reducing non-specific interactions and not hindering the effect of the biomolecule. However, taken into account the numerous advantages of a synthetic and customizable polymer chain over a complex natural protein, PEG blocking stands out as a very good alternative to albumin adsorption.Peer ReviewedAward-winnin

    Desenvolupament d’un tractament antiadherent de superfícies de titani per a aplicacions biomèdiques

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    L‚Äô√ļs d‚Äôimplants de titani per a traumatologia i odontologia √©s una pr√†ctica molt estesa actualment. El seu √®xit, per√≤, es veu afectat pels casos de infeccions que pateixen. En el cas concret dels implants dentals, el 14% dels implants pateixen infeccions bacterianes i entre el 5 i el 8% presenten infecci√≥ bacteriana que desenvolupa una peri-implantitis i una conseq√ľent p√®rdua de l‚Äôimplant. Per aquest motiu, en els darrers anys s‚Äôha estudiat el desenvolupament de superf√≠cies antibacterianes. En aquest treball s‚Äôoptimitza un tractament antiadherent per a superf√≠cies de titani amb l‚Äôobjectiu de minimitzar l‚Äôadhesi√≥ bacteriana que pugui produir una infecci√≥ posterior. S‚Äôha desenvolupat un tractament de la superf√≠cie de titani per formar un recobriment amb un pol√≠mer antiadherent. S‚Äôhan estudiat les caracter√≠stiques fisicoqu√≠miques de la superf√≠cie que en resulta. Tamb√© s‚Äôha estudiat la seva biocompatibilitat i capacitat per evitar l‚Äôadhesi√≥ de prote√Įnes i bacteris.The use of titanium implants for orthopedic and dental practice is currently widespread. Its success, however, is affected by implant-related infections. In the case of dental implants, 14% of implants suffered bacterial infections and between 5 and 8% have a bacterial infection that develops peri-implantitis and consequent loss of the implant. For this reason, in the recent years the development of antibacterial surfaces has been thoroughly studied. In this paper, a treatment has been optimized for creating antifouling titanium surfaces with the objective to minimize bacterial adhesion that may result in an infection. The titanium surface treatment produces a coating with an antifouling polymer. The physicochemical characteristics of the resulting surface have been studied, as well as the biocompatibility and the ability to prevent the adhesion of proteins and bacteria.Peer Reviewe
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