Effect of Surface Charge and Hydrophobicity Modulation on the Antibacterial and Antibiofilm Potential of Magnetic Iron Nanoparticles

Unmodified magnetic nanoparticles (MNPs) lack antibacterial potential. We investigated MNPs surface modifications that can impart antibacterial activity. Six MNPs species were prepared and characterized. Their antibacterial and antibiofilm potentials, surface affinity, and cytotoxicity were evaluated. Prepared MNPs were functionalized with citric acid, amine group, amino-propyl trimethoxy silane (APTMS), arginine, or oleic acid (OA) to give hydrophilic and hydrophobic MNPs with surface charge ranging from −30 to +30 mV. Prepared MNPs were spherical in shape with an average size of 6–15 nm. Hydrophobic (OA-MNPs) and positively charged MNPs (APTMS-MNPs) had significant concentration dependent antibacterial effect. OA-MNPs showed higher inhibitory potential against S. aureus and E. coli (80%) than APTMS-MNPs (70%). Both particles exhibited surface affinity to S. aureus and E. coli. Different concentrations of OA-MNPs decreased S. aureus and E. coli biofilm formation by 50–90%, while APTMS-MNPs reduced it by 30–90%, respectively. Up to 90% of preformed biofilms of S. aureus and E. coli were destroyed by OA-MNPs and APTMS-MNPs. In conclusion, surface positivity and hydrophobicity enhance antibacterial and antibiofilm properties of MNPs

Impact des bruits d'alimentations et des signaux parasites sur l'intégrité des signaux ultra-rapides

National audiencePour répondre aux besoins croissants des systèmes électroniques en performance et en rapidité, l'électronique numérique a rejoint l'analogique pour former des circuits mixtes ultra-rapides. De cette mixité émerge la nécessité de contrôler l'intégrité des signaux échangés entre les composants, et de leur assurer une bonne protection contre les éventuelles perturbations causées par leur environnement. Cet article présente les caractéristiques des modules critiques présents sur des cartes électroniques à haute densité et à forte puissance employées pour le calcul haute performance, ainsi que les problématiques liées à leur cohabitation

Effect of Surface Charge and Hydrophobicity Modulation on the Antibacterial and Antibiofilm Potential of Magnetic Iron Nanoparticles

© 2017 Rania Ibrahim Shebl et al. Unmodified magnetic nanoparticles (MNPs) lack antibacterial potential. We investigated MNPs surface modifications that can impart antibacterial activity. Six MNPs species were prepared and characterized. Their antibacterial and antibiofilm potentials, surface affinity, and cytotoxicity were evaluated. Prepared MNPs were functionalized with citric acid, amine group, amino-propyl trimethoxy silane (APTMS), arginine, or oleic acid (OA) to give hydrophilic and hydrophobic MNPs with surface charge ranging from -30 to +30 mV. Prepared MNPs were spherical in shape with an average size of 6-15 nm. Hydrophobic (OA-MNPs) and positively charged MNPs (APTMS-MNPs) had significant concentration dependent antibacterial effect. OA-MNPs showed higher inhibitory potential against S. aureus and E. coli (80%) than APTMS-MNPs (70%). Both particles exhibited surface affinity to S. aureus and E. coli. Different concentrations of OA-MNPs decreased S. aureus and E. coli biofilm formation by 50-90%, while APTMS-MNPs reduced it by 30-90%, respectively. Up to 90% of preformed biofilms of S. aureus and E. coli were destroyed by OA-MNPs and APTMS-MNPs. In conclusion, surface positivity and hydrophobicity enhance antibacterial and antibiofilm properties of MNPs

LC–MS/MS assay for assessing medical adherence in patients under warfarin maintenance therapy

Warfarin (WRN) use is plagued by response fluctuation which is managed by dose adjustment. The plasma WRN level had always been an abandoned prerequisite for dose adjustment. However, recent reports had correlated WRN level to the consumed dose. More importantly, the intra-individual alteration in WRN level was found proportional to response fluctuation. This renewed the interest to use WRN level prior to dose adjustment to account for dispensing errors or inadequate adherence. Detection of possibly interacting drugs may further assess compliance and enable a wiser dose adjustment. In this study, an LC–MS/MS assay was developed and validated for the determination of the WRN and the simultaneous detection of interacting drugs in citrated plasma samples normally collected for monitoring international normalized ration (INR). Samples were prepared by liquid-liquid extraction. Separation of WRN and interacting drugs (n = 19) was achieved on an Inertsil®C18 column using a gradient elution program. The assay was applied in 96 plasma samples from patients. The developed method was linear, accurate and precise for WRN determination with average recovery of 99.5 ± 8.4% and no relative matrix effect. WRN plasma level was measured in all samples and possible interacting drugs were detected. An improved WRN-response correlation was observed inter-individually when patient variability was reduced. Our results support the significance of WRN monitoring and suggest the additional monitoring of other interacting drugs for integrated evaluation of patient adherence. The developed method enables ruling-out inadequate adherence prior to unnecessary dose adjustment and highlights the need to strengthen patient education procedures