Papers by Patricia Schilardi
New technologies involve a complex interplay of technical and social factors. The innovation that... more New technologies involve a complex interplay of technical and social factors. The innovation that will produce nanotechnology and their benefits into society are only partially understood and constitute valuable issues to inform and discuss. The academic formation and scientific training of teachers and researchers from universities and scientific system is what allows to implement and carry out the task to inform and diffuse the impact and scope of technological innovations in N&N. This paper discusses the actions carried out in Argentina in the area of diffusion of N&N in different educational settings, broadcast media and events with massive participation of the society.
Riboflavin-mediated photooxidation of gold nanoparticles and its effect on the inactivation of ba... more Riboflavin-mediated photooxidation of gold nanoparticles and its effect on the inactivation of bacteria.
Con el objetivo de producir materiales biológicamente activos y biocompatibles para inhibir y com... more Con el objetivo de producir materiales biológicamente activos y biocompatibles para inhibir y combatir el crecimiento bacteriano en dispositivos implantables, se modificaron superficies de Ti con lactoferrina, una proteína con capacidad antibacteriana comprobada, y además se funcionalizaron con esta proteína nanopartículas de plata previamente estudiadas por su efecto antimicrobiano.
autoriza la reproducción total o parcial de este artículo, siempre y cuando se cite la fuente com... more autoriza la reproducción total o parcial de este artículo, siempre y cuando se cite la fuente completa y su dirección electrónica.
Materials Science and Engineering: C, Apr 1, 2016
Biofilms formed on implanted devices are difficult to eradicate. Adhesion mechanism, high bacteri... more Biofilms formed on implanted devices are difficult to eradicate. Adhesion mechanism, high bacterial density, aggregation, induction of persisters and stressed bacteria are some of the factors considered when the antimicrobial resistance of these biofilms is analyzed. The aim of this work was to provide an alternative approach to the understanding of this issue by using a specially designed experimental set up that includes the use of microstructured (MS) surfaces (potential inhibitors of bacterial aggregation) in combination with antimicrobial agents (streptomycin and levofloxacin) against Staphylococcus aureus attached cells. Biofilms formed on smooth surfaces were used as plain controls (biofilmed-PC) characterized by the formation of dense 2D bacterial aggregates. Results showed bacterial persistence when streptomycin or levofloxacin were applied to PC-biofilms. The antimicrobial activity of both antibiotics was enhanced when bacteria were attached on MS, where single cells or small aggregates were observed. Thus, dense 2D aggregates of bacteria seem to be crucial as a required previous stage to develop the antimicrobial resistance.
Estrategias de difusión de la Nanociencia y la Nanotecnología en
Revista digital universitaria, Mar 15, 2017
Las nuevas tecnologias implican una interaccion compleja de factores tecnicos y sociales. La inno... more Las nuevas tecnologias implican una interaccion compleja de factores tecnicos y sociales. La innovacion que producira la nanotecnologia y sus beneficios en la sociedad son parcialmente comprendidos y constituyen temas valioso para informar y discutir. La formacion academica y trayectoria cientifica de docentes e investigadores de universidades y del sistema cientifico es lo que permite implementar y llevar adelante la tarea de informar y difundir el impacto y alcance de las innovaciones tecnologicas en N&N. En este trabajo se comentan las acciones que se llevan a cabo en Argentina en el campo de la divulgacion en N &N en distintos ambitos educativos, difusion en medios de comunicacion y eventos de participacion masiva de la sociedad.
Contraception, 2012
Background: The copper intrauterine device is a contraceptive method that is based on the release... more 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. The dissolution of copper with and without pretreatments in TU and PU solutions was analyzed by conventional electrochemical techniques and surface analysis. Results: Pretreatments in PU solutions reduced the initial corrosion rate of copper in simulated uterine solutions, with inhibitory efficiencies that depend on the PU concentration and on the immersion time assayed. Inhibitory efficiency values higher than 98% for pretreatments with ≥10 −3 M PU were found. Conversely, after TU pretreatments, a high copper release was measured. Conclusions: It was concluded that 10 −3 M PU pretreatment is a promising strategy able to reduce the "burst release" of copper and to ensure contraceptive action.
Colloids and Surfaces B: Biointerfaces, Feb 1, 2021
Organization of <i>Pseudomonas fluorescens</i> on Chemically Different Nano/Microstructured Surfaces
ACS Applied Materials & Interfaces, Aug 20, 2010
This paper describes bacterial organization on nano/micropatterned surfaces with different chemic... more 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. Results from atomic force microscopy and optical imaging demonstrate that the structure of P. fluorescens aggregates is strongly dependent on the surface topography while there is no clear linking with the physical-chemical surface properties (charge and contact angle) of the substrate immersed in abiotic culture media. We observe that regardless of the material when the surface pattern matches the bacterial size, bacterial assemblages involved in surface colonization are disorganized. The fact there is not a relationship between surface chemistry and bacterial organization can be explained by the coverage of the surfaces by adsorbed organic species coming from the culture medium. Viability assays indicate that copper behaves as a toxic substrate despite the presence of adsorbed molecules. The combination of surface traps and biocidal activity could act synergistically as a suitable strategy to limit bacterial spreading on implant materials.
Encuentro de Becarios de la UNLP (EBEC) (La Plata, 2018), Mar 26, 2019
Surface nanopatterning of hard and soft thin films by a replica-molding approach
Hidrogeles Biodegradables Sobre Superficies De Interés en Cirugía Protésica: Hacia Un Sistema Óptimo Para La Liberación Local De Agentes Terapéuticos
Encuentro de Becaries de Posgrado de la UNLP (EBEC) (Modalidad virtual, 12 de noviembre de 2020), 2020
Dental Materials, Dec 1, 2020
Starch is an edible polymer which may be used in combination with antimicrobial agents as thin co... more Starch is an edible polymer which may be used in combination with antimicrobial agents as thin coatings to extend shelf life of foods. This work was aimed to design and characterize an oleic acid nanoemulsion (OAN), as part of starch-based edible coating (EC) suspensions, incorporated with a mixture of three natural antimicrobials: lactic acid (ALA), nisin (NIS), and lauric arginate (LAE). OANs contained finely dispersed hydrophobic particles of 95.9 ± 4.8 nm providing a stable suspension, and high optical clarity (27843.6 ± 230.2 Transmittance units/nm). The EC suspension was prepared using waxy, acetylated cross linked, or oxidized starches (4% w/v) mixed with sorbitol (0.8 g/g starch), to which the nanoemulsion was added, and physicochemically characterized. The z potential of the OAN showed a large value (À35.08 ± 1.26 mV). Despite EC suspensions showed low z potential values, no particles aggregation was observed after 4 months storage. The wettability coefficient (Ws) of EC suspensions was tested on three model foods, where those of waxy and oxidized starches gave Ws ¼ À0.01 ± 0.0 mN/m for fresh pork meat, with contact angle of 0. The EC suspension from waxy starch was tested to inhibit Brochothrix thermosphacta, Listeria monocytogenes Scott A and Micrococcus luteus ATCC 11509, alone, and in mixture. From a mixture design of experiments the optimum combination of antimicrobial agents was 3.75 mg/mL NIS, 0.0625 mg/mL LAE, and 17.5 mg/mL ALA, which incorporated into EC suspensions produced similar antimicrobial effect. The properties of active EC suspensions may be used as coatings to extend the shelf life of fresh foods.
Silica-Coated Magnetic Particles for Efficient RNA Extraction for SARS-CoV-2 Detection
Fil: Alvarez, Florencia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cient... more Fil: Alvarez, Florencia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico la Plata. Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas; Argentina
Photochemistry and Photobiology, 2020
Mono‐ and bis‐decylated lumazines have been synthesized and characterized. Namely, mono‐decyl cha... more Mono‐ and bis‐decylated lumazines have been synthesized and characterized. Namely, mono‐decyl chain [1‐decylpteridine‐2,4(1,3H)‐dione] 6a and bis‐decyl chain [1,3‐didecylpteridine‐2,4(1,3H)‐dione] 7a conjugates were synthesized by nucleophilic substitution (SN2) reactions of lumazine with 1‐iododecane in N,N‐dimethylformamide (DMF) solvent. Decyl chain coupling occurred at the N1 site and then the N3 site in a sequential manner, without DMF condensation. Molecular orbital (MO) calculations show a p‐orbital at N1 but not N3, which along with a nucleophilicity parameter (N) analysis predict alkylation at N1 in lumazine. Only after the alkylation at N1 in 6a, does a p‐orbital on N3 emerge thereby reacting with a second equivalent of 1‐iododecane to reach the dialkylated product 7a. Data from NMR (1H, 13C, HSQC, HMBC), HPLC, TLC, UV‐vis, fluorescence and density functional theory (DFT) provide evidence for the existence of mono‐decyl chain 6a and bis‐decyl chain 7a. These results differ...
Colloids and surfaces. B, Biointerfaces, 2018
The use of indwelling devices has emerged as a frequent and often life-saving medical procedure. ... more The use of indwelling devices has emerged as a frequent and often life-saving medical procedure. However, infection in prosthetic surgery is one of the most important and devastating complications. Once the biofilm has been formed, its eradication is extremely difficult, due to an increased resistance to host defense and conventional antimicrobials. Thus, the design of novel strategies for inhibiting the bacterial adhesion on implantable devices is a key point for successful surgical procedures. In this work, the development of a simple two-step protocol to prepare surfaces able to prevent the bacterial growth was successfully achieved. The surface-modification design includes a combined approach involving the multi-functionalization of Ti surfaces with silver nanoparticles (AgNPs) and/or ampicillin (AMP). The surface chemistry involved in AMP adsorption on titanium and silver surfaces was elucidated for the first time, thus establishing the basis for the further anchoring of other ...
Self-assembly of flagellin on Au(111) surfaces
Journal of Colloid and Interface Science, 2014
The adsorption of flagellin monomers from Pseudomonas fluorescens on Au(111) has been studied by ... more The adsorption of flagellin monomers from Pseudomonas fluorescens on Au(111) has been studied by Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy (STM), X-ray Photoelectron Spectroscopy (XPS), Surface Plasmon Resonance (SPR), and electrochemical techniques. Results show that flagellin monomers spontaneously self-assemble forming a monolayer thick protein film bounded to the Au surface by the more hydrophobic subunit and exposed to the environment the hydrophilic subunit. The films are conductive and allow allocation of electrochemically active cytochrome C. The self-assembled films could be used as biological platforms to build 3D complex molecular structures on planar metal surfaces and to functionalize metal nanoparticles.
Applied Physics A, 2005
Rapid communication Materials Science & Processing Applied Physics A o. azzaroni 1,2,u p.l. schil... more Rapid communication Materials Science & Processing Applied Physics A o. azzaroni 1,2,u p.l. schilardi 2 r.c. salvarezza 2 j. manuel-herrero 3 c. zaldo 3 l. vázquez 3 Surface-relief micropatterning of zinc oxide substrates by micromolding pulsed-laser-deposited films
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Papers by Patricia Schilardi