Publications by authors named "Miguel A Pacha-Olivenza"

Interest in biodegradable implants has focused attention on the resorbable polymer polylactic acid. However, the risk of these materials promoting infection, especially in patients with existing pathologies, needs to be monitored. The enrichment of a bacterial adhesion medium with compounds that are associated with human pathologies can help in understanding how these components affect the development of infectious processes.

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The improvement of biodegradable metals is currently an active and promising research area for their capabilities in implant manufacturing. However, controlling their degradation rate once their surface is in contact with the physiological media is a challenge. Surface treatments are in the way of addressing the improvement of this control.

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Diabetes is a widely spread disease affecting the quality of life of millions of people around the world and is associated to a higher risk of developing infections in different parts of the body. The reasons why diabetes enhances infection episodes are not entirely clear; in this study our aim was to explore the changes that one of the most frequently pathogenic bacteria undergoes when exposed to hyperglycemia and ketoacidosis conditions. Physical surface properties such as hydrophobicity and surface electrical charge are related to bacterial growth behavior and the ability of Staphylococcus aureus to form biofilms.

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Bacterial contamination in implanted biomedical devices is a critical daily concern. The most used material for permanent implant in biomedical field is Ti6Al4V alloy due to its beneficial mechanical properties and high biocompatibility. Accordingly, in this work different polymeric antibacterial coatings poly(N-vinyl pyrrolidone) (PVP), hyaluronic acid (HA) and chitosan (CHI) were developed and comparatively analysed for Ti6Al4V surface covering.

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Magnesium is currently increasing interest in the field of biomaterials. An extensive bibliography on this material in the last two decades arises from its potential for the development of biodegradable implants. In addition, many researches, motivated by this progress, have analyzed the performance of magnesium in both in vitro and in vivo assays with gram-positive and gram-negative bacteria in a very broad range of conditions.

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Controlling initial bacterial adhesion is essential to prevent biofilm formation and implant-related infection. The search for surface coatings that prevent initial adhesion is a powerful strategy to obtain implants that are more resistant to infection. Tracking the progression of adhesion on surfaces from the beginning of the interaction between bacteria and the surface provides a deeper understanding of the initial adhesion behavior.

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Dental implantology allows replacement of failing teeth providing the patient with a general improvement of health. Unfortunately not all reconstructions succeed, as a consequence of the development of infections of bacterial origin on the implant surface. Surface topography is known to modulate a differential response to bacterial and mammalian cells but topographical measurements are often limited to vertical parameters.

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Bacterial contamination is a critical problem in medical implants, which are preferential sites for bacterial adhesion, leading to infections which can compromise health and immune system of patients. Commercial titanium alloys are the most commonly used materials for permanent implants in contact with bone, and the prevention of infections on their surface is therefore a crucial challenge for orthopaedic and dental surgeons. Thus, the aim of this work is to develop polysaccharide antibacterial coatings onto modified titanium surfaces with different surface topography, in order to act as reservoirs of antibacterial agents.

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The effects of surface modifications and bacteria on the corrosion behavior of titanium have been studied. Five surface modifications were analyzed: two acid etchings (op V, op N), acid etching + anodic oxidation (op NT), sandblasting + acid etching (SLA), and machined surfaces (mach). The corrosion behavior of the surface modifications was evaluated by following the standard ANSI/AAMI/ISO 10993-15:2000.

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Implant integration is a complex process mediated by the interaction of the implant surface with the surrounding ions, proteins, bacteria, and tissue cells. Although most implants achieve long-term bone-tissue integration, preventing pervasive implant-centered infections demands further advances, particularly in surfaces design. In this work, we analyzed classical microrough implant surfaces (only acid etched, AE; sandblasted then acid etching, SB + AE) and a new calcium-ion-modified implant surface (AE + Ca) in terms of soft- and hard-tissue integration, bacterial adhesion, and biofilm formation.

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Background: Biomaterial-associated infections are one of the most important complications in orthopedic surgery. The main goal of this study was to demonstrate the in vivo bactericidal effect of ultraviolet (UV) irradiation on Ti6Al4V surfaces.

Materials And Methods: An experimental model of device-related infections was developed by direct inoculation of Staphylococcus aureus into the canal of both femurs of 34 rats.

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Myo-inositol hexaphosphate, also called phytic acid or phytate (IP6), is a natural molecule abundant in vegetable seeds and legumes. Among other functions, IP6 inhibits bone resorption. It is adsorbed on the surface of hydroxyapatite, inhibiting its dissolution and decreasing the progressive loss of bone mass.

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Many dental implants fail due to the infection and inflammation that walk hand in hand with poor healing and soft tissue integration. Titanium surfaces were nanocoated with quercitrin, a natural flavonoid, with the aim to improve soft tissue integration and increase dental implants success. Streptococcus mutans attachment and biofilm formation was analysed.

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This research investigates in detail the bactericidal effect exhibited by the surface of the biomaterial Ti6Al4V after being subjected to UV-C light. It has been recently hypothesized that small surface currents, occurring as a consequence of the electron-hole pair recombination taking place after the excitation process, are behind the bactericidal properties displayed by this UV-treated material. To corroborate this hypothesis we have used different electrochemical techniques, such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization plots and Mott-Schottky plots.

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Biomaterial implant-associated infections, a common cause of medical devices' failure, are initiated by bacterial adhesion to an adsorbed protein layer on the implant material surface. In this study, the influence of protein surface orientation on bacterial adhesion has been examined using three clinically relevant bacterial strains known to express specific binding sites for human plasma fibronectin (HFN). HFN was allowed to adsorb on hydrophobic Ti6Al4V and physically modified hydrophilic Ti6Al4V substrata.

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TiO(2)-coated biomaterials that have been excited with UV irradiation have demonstrated biocidal properties in environmental applications, including drinking water decontamination. However, this procedure has not been successfully applied towards the killing of pathogens on medical titanium-based implants, mainly because of practical concerns related to irradiating the inserted biomaterial in situ. Previous researchers assumed that the photocatalysis on the TiO(2) surface during UV application causes the bactericidal effects.

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UV irradiation leads to a "spontaneous" wettability increase of the Ti6Al4V surface while preserving bulk properties of the alloy that are crucial for its performance as an orthopedic and dental implant. We hypothesized that UV treatment of Ti6Al4V may impair bacterial adhesion without compromising the good response of human bone-forming cells to this alloy. The in vitro biocompatibility of the Ti6Al4V surface, before and after UV irradiation, was analyzed by using human cells related to the osteoblastic phenotype.

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