Innovative Anodic Treatment to Obtain Stable Metallic Silver Micropatches on TiO Nanotubes: Structural, Electrochemical, and Photochemical Properties.

Electrochemical modification of the Ti surface to obtain TiO nanotubes (NT-Ti) has been proposed to enhance osseointegration in medical applications. However, susceptibility to microbial adhesion, linked to biomaterial-associated infections, and the high TiO band gap energy, which allows light absorption almost exclusively in the ultraviolet (UV) region, limit its applications. Modifying the TiO semiconductor with metals such as Ag has been suggested both for antimicrobial purposes and for absorbing light in the visible region.

Different Impact of Suspended AlO Nanoparticles on Microbial Communities: Formation of 2D-Networks (Without Humic Acids) or 3D-Colonies (With Humic Acids).

The use of metal-based and, particularly, AlO nanoparticles (AlO-NP) for diverse purposes is exponentially growing. However, the growth of such promissory market is not accompanied by a parallel extensive investigation related to the impact of this pollution on groundwater and biological systems. Pseudomonas species, ubiquitous, environmentally critical microbes, frequently respond to stress conditions with diverse strategies that generally include extracellular polymeric substances (EPS) formation.

Environmentally Induced Changes of Commercial Carbon Nanotubes in Aqueous Suspensions. Adaptive Behavior of Bacteria in Biofilms.

The effects of environmental factors such as sunlight irradiation and the presence of humic acid (HA) on the physicochemical properties of commercial multiwall carbon nanotubes (MWCNT) suspended in a simulated inorganic matrix (SIM) and their impacts on bacteria growing in biofilms were evaluated. Both solar irradiation and the presence of HA lead to the dissolution of adsorbed metals on the MWCNT, which are residues of synthesis catalysts. Also, preferential adsorption of certain HA components on the MWCNT induces important modifications in the aliphatic/aromatic relationship of HA components in solution and the generation and release of new moieties.

Effect of degradation products of iron-bioresorbable implants on the physiological behavior of macrophages in vitro.

The degradation of bioresorbable metals in vivo changes the physicochemical properties in the environment of an implant, such as a stent in the artery wall, and may induce the alteration of the functions of the surrounding cells. The Fe-degradation, from bioresorbable stents, is a particularly intricate process because it leads to the release of soluble (SDP) and insoluble degradation products (IDP) of varied composition. Macrophages are involved in the resorption of the exogenous agents coming from degradation of these materials.

Staphylococcus aureus biofilm eradication by the synergistic effect exerted by PEG-coated silicon dots immobilized in silica films and light irradiation.

Immobilization of PEG-covered silicon dots, PEGSiDs, on glass substrates was performed following a simple strategy involving particle embedding by a sol-gel process forming a silica film on glass slides. The obtained films, denoted as fSiO -PEGSiD, constitute a water-wettable, strongly supported, photoluminescent glass coating. The films showed high capacity for photosensitizing singlet oxygen (O) in the UVA when immersed in water.

Characterization and antimicrobial effect of a bioinspired thymol coating formed on titanium surface by one-step immersion treatment.

Objective: To develop an antimicrobial and anti-adherent thymol (TOH)-containing coating on titanium (Ti) by a bioinspired one-step biocompatible method.

Methods: A nanolayer of adsorbed TOH (TOH-NL-Ti) was formed by an easy deep coating method on Ti surface. The treatment consists in a simple one-step immersion process in a TOH-containing solution.

Synergistic effect of carboxypterin and methylene blue applied to antimicrobial photodynamic therapy against mature biofilm of .

The control of multidrug-resistant (MDR) bacteria is a growing public health problem, and new strategies are urgently needed for the control of the infections caused by these microorganisms. Notoriously, some MDR microorganisms generate complex structures or biofilms, which adhere to surfaces and confer extraordinary resistance properties that are fundamental challenges to control infections. One of the promising strategies for the control of MDR bacteria is antimicrobial photodynamic therapy (aPDT), which takes advantage of suitable photosensitizers (PS), oxygen and radiation to eradicate microorganisms by the generation of highly reactive species, including reactive oxygen species (ROS) that cause cytotoxic damage and cell death.

Comparative study of transdermal drug delivery systems of resveratrol: High efficiency of deformable liposomes.

Trans-resveratrol (3, 5, 4' trihydroxystilbene, RSV) is a natural compound that shows antioxidant, cardioprotective, anti-inflammatory and anticancer properties. The transdermal, painless application of RSV is an attractive option to other administration routes owing to its several advantages like avoiding gastrointestinal problems and first pass metabolism. However, its therapeutic potential is limited by its low solubility and low stability in water and the reduced permeability of stratum corneum.

Self-sterilizing ormosils surfaces based on photo-synzthesized silver nanoparticles.

Medical device-related infections represent a major healthcare complication, resulting in potential risks for the patient. Antimicrobial materials comprise an attractive strategy against bacterial colonization and biofilm proliferation. However, in most cases these materials are only bacteriostatic or bactericidal, and consequently they must be used in combination with other antimicrobials in order to reach the eradication condition (no viable microorganisms).

Resveratrol enhancement staphylococcus aureus survival under levofloxacin and photodynamic treatments.

Reactive oxygen species (ROS) are an efficient tool to eradicate micro-organisms owing to the capacity of these species to damage almost all types of biomolecules and to kill cells. The increase in mechanisms of antimicrobial resistance has led to the exploration of new strategies to eliminate micro-organisms that involve the production of ROS such as superoxide anion (O) and hydrogen peroxide (HO). ROS are produced during several antimicrobial treatments, including antibiotic and photodynamic therapies.

Is there any difference in the biological impact of soluble and insoluble degradation products of iron-containing biomaterials?

The interactions that could be built between the biomaterials and tissue- microenvironments are very complex, especially in case of degradable metals that generate a broad variety of degradation products. The interfacial problems are particularly relevant for Fe-based materials that have been proposed for the development of biodegradable implants. The cell metabolism could be affected by the accumulation of insoluble Fe-containing degradation products that has been observed in vitro and in vivo as a coarse granular brownish material around the implant.

Polyethylene glycol-coated blue-emitting silicon dots with improved properties for uses in aqueous and biological environments.

Grafting of polyethylene glycol (PEG) to ultrasmall photoluminescent silicon dots (SiDs) is expected to improve and expand the applications of these particles to aqueous environments and biological systems. Herein we report a novel one-pot synthesis of robust, highly water compatible PEG-coated SiDs (denoted as PEG-SiDs) of (3.3 ± 0.

Delivery of fluorophores by calcium phosphate-coated nanoliposomes and interaction with Staphylococcus aureus biofilms.

The delivery capacity and mechanical stability of calcium phosphate (CaP) coated 1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) liposomes free and adsorbed on bacterial surface was investigated introducing either acridine orange (AO) or 5,10,15,20-Tetrakis(1-methyl-4-pyridinio)porphyrin (TMP) in the aqueous core of the liposomes. The obtained nanomaterials were thoroughly characterized by electron and optical microscopy and by fluorescence techniques. Distribution of the AO and TMP molecules between the aqueous liposomes core and the outer solution was demonstrated by the band shifts and broadening of the excitation-emission matrices and the modified Stern-Volmer model for fluorescence quenching.

Time-Lapse Evaluation of Interactions Between Biodegradable Mg Particles and Cells.

Mg-based implants have promising applications as biodegradable materials in medicine for orthopedic, dental, and cardiovascular therapies. During wear and degradation microdebris are released. Time-lapse multidimensional microscopy (MM) is proposed here as a suitable tool to follow, in fixed intervals over 24-h periods, the interaction between cells and particles.

Degradation of bioabsorbable Mg-based alloys: Assessment of the effects of insoluble corrosion products and joint effects of alloying components on mammalian cells.

This work is focused on the processes occurring at the bioabsorbable metallic biomaterial/cell interfaces that may lead to toxicity. A critical analysis of the results obtained when degradable metal disks (pure Mg and rare earth-containing alloys (ZEK100 alloys)) are in direct contact with cell culture and those obtained with indirect methods such as the use of metal salts and extracts was made. Viability was assessed by Acridine Orange dye, neutral red and clonogenic assays.

Photodynamic inactivation induced by carboxypterin: a novel non-toxic bactericidal strategy against planktonic cells and biofilms of Staphylococcus aureus.

Microbial related contamination is of major concern and can cause substantial economic losses. Photodynamic inactivation (PDI) has emerged as a suitable approach to inhibit microorganism proliferation. In this work, PDI induced by 6-carboxypterin (Cap), a biocompatible photosensitizer (PS), was analyzed.

Cytotoxicity of corrosion products of degradable Fe-based stents: relevance of pH and insoluble products.

Fe-based biodegradable metallic materials (Fe-BMMs) have been proposed for cardiovascular applications and are expected to disappear via corrosion after an appropriate period. However, in vivo studies showed that Fe ions release leads to accumulation of orange and brownish insoluble products at the biomaterial/cell interface. As an additional consequence, sharp changes in pH may affect the biocompatibility of these materials.

Synergistic cytotoxic effects of ions released by zinc-aluminum bronze and the metallic salts on osteoblastic cells.

The use of copper-based alloys for fixed dental crowns and bridges is increasingly widespread in several countries. The aim of this work is to study the dissolution of a zinc-aluminum-bronze and the cytotoxic effects of the ions released on UMR-106 osteoblastic cell line. Two sources of ions were used: (1) ions released by the metal alloy immersed in the cell culture and (2) salts of the metal ions.

Decrease in cytotoxicity of copper-based intrauterine devices (IUD) pretreated with 6-mercaptopurine and pterin as biocompatible corrosion inhibitors.

The copper intrauterine device (IUD) based its contraceptive action on the release of cupric ions from a copper wire. Immediately after the insertion, a burst release of copper ions occurs, which may be associated to a variety of side effects. 6-Mercaptopurine (6-MP) and pterin (PT) have been proposed as corrosion inhibitors to reduce this harmful release.

Chlorhexidine delivery system from titanium/polybenzyl acrylate coating: evaluation of cytotoxicity and early bacterial adhesion.

Objectives: The formation of biofilms on titanium dental implants is one of the main causes of failure of these devices. Streptococci are considered early colonizers that alter local environment favouring growing conditions for other colonizers. Chlorhexidine (CHX) is so far the most effective antimicrobial treatment against a wide variety of Gram-positive and Gram-negative organisms as well as fungi.

Reduction of the "burst release" of copper ions from copper-based intrauterine devices by organic inhibitors.

Background: The copper intrauterine device is a contraceptive method that is based on the release of copper ions from a copper wire. Immediately after insertion, the dissolution of copper in the uterine fluid is markedly higher ("burst release") than that necessary for contraception action, leading to a variety of harmful effects.

Study Design: Pretreatments with organic compounds [thiourea (TU) and purine (PU), 10(-4)-10(-2) M concentration range, 1- and 3-h immersion times] were tested.

Biocompatibility of magnesium particles evaluated by in vitro cytotoxicity and genotoxicity assays.

Mg is a biodegradable biomaterial which may release particles (MP) to the environment. The possible cyto- and genotoxic effects of MP derived from magnesium powder (mesh 325) were analyzed on rat osteosarcoma UMR106 cells in order simulate the effect of Mg debris. Neutral red (NR) incorporation and acridine orange/ethidium bromide (AO/EB) staining techniques were used as endpoints to analyze the cytotoxic effects at 25-1000 μg/mL concentration range.

Organization of Pseudomonas fluorescens on chemically different nano/microstructured surfaces.

This paper describes bacterial organization on nano/micropatterned surfaces with different chemical properties, which show different interactions with the biological systems (inert, biocompatible, and bactericide). These surfaces were prepared by molding techniques and exposed to Pseudomonas fluorescens (P. fluorescens) cultures.

Critical discussion of the results from different corrosion studies of Mg and Mg alloys for biomaterial applications.

The aim of this work was to collect and compare data from different published reports which focused on the description of the influence of different electrochemical setups for the assessment of magnesium corrosion. Based on this, a comparison with our own results, obtained for LAE 442 and AZ 31, was made and discussed. As the collection of data has shown, the reported inconsistencies between in vivo and electrochemical data depend greatly on the electrochemical medium used, on the alloy composition and on surface preparation.

Submicron trenches reduce the Pseudomonas fluorescens colonization rate on solid surfaces.

Bacterial adhesion and spreading on biomaterials are considered key features of pathogenicity. Roughness and topography of the substrate have been reported to affect bacterial adhesion, but little is known about their effect on spreading. Submicron row and channel tuning with bacterial diameter (S2) were designed to test bacterial motility on these surfaces.