Effect of AgNPs and AgNPs-go on the bioadhesion of <i>Pseudomonas aeruginosa</i> on stainless steel surfaces

With the aim of incorporating nanohybrid materials in antimicrobial coatings, the inhibition of the adhesion of Pseudomonas aeruginosa on 430 AISI stainless steel coupons exposed to AgNPs and AgNPs-GO solutions was studied. AgNPs were obtained by green synthesis, while AgNPs-GO by exsitu and in-situ synthesis. Coupons were immersed in these solutions, to form a coating. Bacterial adherence values obtained were: 105-106 CFU.cm-2 for coupons without coating; 104-105 CFU.cm-2 for AgNPs-GO (in-situ) coupons and values lower than 102 CFU.cm-2 on AgNPs and AgNPs-GO (exsitu) coupons. These results were corroborated by scanning electron microscopy observations.Centro de Investigación y Desarrollo en Tecnología de Pintura

Effect of AgNPs and AgNPs-go on the bioadhesion of <i>Pseudomonas aeruginosa</i> on stainless steel surfaces

With the aim of incorporating nanohybrid materials in antimicrobial coatings, the inhibition of the adhesion of Pseudomonas aeruginosa on 430 AISI stainless steel coupons exposed to AgNPs and AgNPs-GO solutions was studied. AgNPs were obtained by green synthesis, while AgNPs-GO by exsitu and in-situ synthesis. Coupons were immersed in these solutions, to form a coating. Bacterial adherence values obtained were: 105-106 CFU.cm-2 for coupons without coating; 104-105 CFU.cm-2 for AgNPs-GO (in-situ) coupons and values lower than 102 CFU.cm-2 on AgNPs and AgNPs-GO (exsitu) coupons. These results were corroborated by scanning electron microscopy observations.Centro de Investigación y Desarrollo en Tecnología de Pintura

Effect of AgNPs and AgNPs-go on the bioadhesion of <i>Pseudomonas aeruginosa</i> on stainless steel surfaces

With the aim of incorporating nanohybrid materials in antimicrobial coatings, the inhibition of the adhesion of Pseudomonas aeruginosa on 430 AISI stainless steel coupons exposed to AgNPs and AgNPs-GO solutions was studied. AgNPs were obtained by green synthesis, while AgNPs-GO by exsitu and in-situ synthesis. Coupons were immersed in these solutions, to form a coating. Bacterial adherence values obtained were: 105-106 CFU.cm-2 for coupons without coating; 104-105 CFU.cm-2 for AgNPs-GO (in-situ) coupons and values lower than 102 CFU.cm-2 on AgNPs and AgNPs-GO (exsitu) coupons. These results were corroborated by scanning electron microscopy observations.Centro de Investigación y Desarrollo en Tecnología de Pintura

Anti-adhesion and antibacterial activity of silver nanoparticles and graphene oxide-silver nanoparticle composites

The rise of nanotechnology has allowed the development of several inorganic nanoparticles with strong biocidal properties against bacteria, fungi, and viruses. Among them, silver nanoparticles (AgNPs) stand out as one of the most promising antimicrobial nanomaterials. Graphene oxide (GO) is another attractive nanomaterial with antimicrobial properties. Although the antimicrobial effect of AgNPs and GO is known, the development of hybrid materials of GO-AgNPs has considerable interest in various applications since they may exhibit synergistic bactericidal properties that exceed the yields of the individual components. The aims of this work were to evaluate the antimicrobial activity and anti-adhesion properties of AgNPs and GO-AgNPs nanocomposites for potential applications in antimicrobial coatings. The antimicrobial activity was tested by agar diffusion method. It was found that activity varied according to the synthesis procedure of the nanomaterials. Pseudomonas aeruginosa, Bacillus cereus and Kokuria rhizophila were the most susceptible strains. The nanocomposite GO- AgNPs synthetized using the ex-situ method exhibited the highest antibacterial activity against all the assayed strains. Similar results were obtained for bacterial adhesion inhibition tests. Thus, GO-AgNPs nanohybrids could be applied as antibacterial coatings to prevent bacterial biofilm development.Centro de Investigación y Desarrollo en Tecnología de PinturasFacultad de Ciencias ExactasComisión de Investigaciones Científicas de la provincia de Buenos Aire

Time to Switch to Second-line Antiretroviral Therapy in Children With Human Immunodeficiency Virus in Europe and Thailand.

Background: Data on durability of first-line antiretroviral therapy (ART) in children with human immunodeficiency virus (HIV) are limited. We assessed time to switch to second-line therapy in 16 European countries and Thailand. Methods: Children aged <18 years initiating combination ART (≥2 nucleoside reverse transcriptase inhibitors [NRTIs] plus nonnucleoside reverse transcriptase inhibitor [NNRTI] or boosted protease inhibitor [PI]) were included. Switch to second-line was defined as (i) change across drug class (PI to NNRTI or vice versa) or within PI class plus change of ≥1 NRTI; (ii) change from single to dual PI; or (iii) addition of a new drug class. Cumulative incidence of switch was calculated with death and loss to follow-up as competing risks. Results: Of 3668 children included, median age at ART initiation was 6.1 (interquartile range (IQR), 1.7-10.5) years. Initial regimens were 32% PI based, 34% nevirapine (NVP) based, and 33% efavirenz based. Median duration of follow-up was 5.4 (IQR, 2.9-8.3) years. Cumulative incidence of switch at 5 years was 21% (95% confidence interval, 20%-23%), with significant regional variations. Median time to switch was 30 (IQR, 16-58) months; two-thirds of switches were related to treatment failure. In multivariable analysis, older age, severe immunosuppression and higher viral load (VL) at ART start, and NVP-based initial regimens were associated with increased risk of switch. Conclusions: One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Material electroactivo impreso 3D basado en compuestos de óxido de grafeno térmicamente reducido y prolicaprolactona para aplicaciones en ingeniería de tejidos

Tesis para optar al grado de Doctora en Ciencias de la Ingeniería, Mención MaterialesUn biomaterial electroactivo entrega estimulación eléctrica (ES) y provoca distintos efectos en células humanas y bacterianas dependiendo del tipo de estímulo aplicado. Se destacan los polímeros electroactivos obtenidos mediante compuestos biocompatibles con partículas conductoras, tales como las basadas en Grafeno. El objetivo de esta investigación fue obtener estructuras tridimensional porosas o scaffolds mediante impresión 3D del compuesto electroactivo de Policaprolactona (PCL) con 10% wt de partículas conductoras de Óxido de Grafeno Reducido Térmicamente (TrGO) para estudiar el efecto de la ES sobre el desempeño celular y reducción bacteriana. Se estudió la relevancia de la temperatura de reducción térmica del Óxido de Grafeno sobre la conducción eléctrica del compósito, y se mostró que a 1000 °C se obtiene un TrGO con menor cantidad de grupos funcionales con respecto a uno reducido a 700 °C, y por lo tanto un compuesto PCL/TrGO de mayor conductividad eléctrica. Este compuesto polimérico fue utilizando para la obtención de scaffolds conductores impresos 3D en los ensayos con células humanas y bacterianas. La presencia de TrGO en la matriz polimérica de PCL permitió modificar la topografía y disminuir la hidrofobicidad de los scaffolds generando un efecto anti-adherente del 40% de S. aureus y duplicando la viabilidad de células madre humanas derivadas de médula ósea (hBM-SCs) con respecto a los scaffolds de PCL puro. Al aplicar 30 V por 3h en corriente directa, se logró una significativa reducción bacteriana del 100% en los scaffolds compuestos en comparación con PCL puro. Se comprobó que este régimen de ES es además citocompatible para hBM-SCs, cuadriplicando su proliferación en los scaffolds PCL/TrGO con respecto al PCL. Por otra parte, se analizó el efecto de un campo eléctrico (EF) de 0.5 V/mm sobre las hBM-SCs adheridas a los scaffolds. En los scaffolds electroactivos PCL/TrGO bajo EF se obtuvieron resultados sobresalientes en la proliferación y potencial diferenciación celular hacia linaje osteoblástico luego 7 días de EF, lo que fue testeado mediante la producción de la proteína alcalina fosfatasa y deposición de calcio bajo EF. Producto de la EF, se modificó la morfología de las células en función a la dirección del EF. Con la obtención de scaffolds conductores de PCL/TrGO mediante impresión 3D se logró obtener una siginificativa reducción bacteriana y una alta citocompatibilidad para células humanas al aplicarse un ES, abriendo nuevas rutas de biomateriales inteligentes para ingeniería de tejidos

Electroactive smart polymers for biomedical applications

© 2019 by the authors.The flexibility in polymer properties has allowed the development of a broad range of materials with electroactivity, such as intrinsically conductive conjugated polymers, percolated conductive composites, and ionic conductive hydrogels. These smart electroactive polymers can be designed to respond rationally under an electric stimulus, triggering outstanding properties suitable for biomedical applications. This review presents a general overview of the potential applications of these electroactive smart polymers in the field of tissue engineering and biomaterials. In particular, details about the ability of these electroactive polymers to: (1) stimulate cells in the context of tissue engineering by providing electrical current; (2) mimic muscles by converting electric energy into mechanical energy through an electromechanical response; (3) deliver drugs by changing their internal configuration under an electrical stimulus; and (4) have antimicrobial behavior du

Effect of AgNPs AND AgNPs-Go on the bioadhesion of Pseudomonas aeruginosa on stainless steel surfaces

With the aim of incorporating nanohybrid materials in antimicrobial coatings, the inhibition of the adhesion of Pseudomonas aeruginosa on 430 AISI stainless steel coupons exposed to AgNPs and AgNPs-GO solutions was studied. AgNPs were obtained by green synthesis, while AgNPs-GO by ex-situ and in-situ synthesis. Coupons were immersed in these solutions, to form a coating. Bacterial adherence values obtained were: 105-106 CFU.cm-2 for coupons without coating; 104-105 CFU.cm-2 for AgNPs-GO (in-situ) coupons and values lower than 102 CFU.cm-2 on AgNPs and AgNPs-GO (ex-situ) coupons. These results were corroborated by scanning electron microscopy observationsFil: Rastelli, Silvia Elena. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Angulo Pineda, Carolina. Universidad de Chile; ChileFil: Palza, Humberto. Universidad de Chile; ChileFil: Viera, Marisa Rosana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas; ArgentinaFil: Gómez de Saravia, Sandra Gabriela. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaCongreso Internacional de Metalurgia y Materiales. 18° SAM-CONAMETBarilocheArgentinaComisión Nacional de Energía AtómicaComisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto BalseiroSociedad Chilena de Metalurgia y MaterialesAsociación Argentina de Materiale

Electroactive 3D printed scaffolds based on percolated composites of polycaprolactone with thermally reduced graphene oxide for antibacterial and tissue engineering applications

Applying electrical stimulation (ES) could affect different cellular mechanisms, thereby producing a bactericidal effect and an increase in human cell viability. Despite its relevance, this bioelectric effect has been barely reported in percolated conductive biopolymers. In this context, electroactive polycaprolactone (PCL) scaffolds with conductive Thermally Reduced Graphene Oxide (TrGO) nanoparticles were obtained by a 3D printing method. Under direct current (DC) along the percolated scaffolds, a strong antibacterial effect was observed, which completely eradicated S. aureus on the surface of scaffolds. Notably, the same ES regime also produced a four-fold increase in the viability of human mesenchymal stem cells attached to the 3D conductive PCL/TrGO scaffold compared with the pure PCL scaffold. These results have widened the design of novel electroactive composite polymers that could both eliminate the bacteria adhered to the scaffold and increase human cell viability, which have great potential in tissue engineering applications.CONICYT-PCHA/Doctorado 21150921 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1150130 Project Millennium Nuclei in Soft Smart Mechanical Metamaterials, Santiago, Chil