Selective adsorption of proteins on single-wall carbon nanotubes by using a protective surfactant

The dispersion of highly hydrophobic carbon materials such as carbon nanotubes in biological media is a challenging issue. Indeed, the nonspecific adsorption of proteins occurs readily when the nanotubes are introduced in biological media; therefore, a methodology to control adsorption is in high demand. To address this issue, we developed a bifunctional linker derived from pyrene that selectively enables or prevents the adsorption of proteins on single-wall carbon nanotubes (SWNTs). We demonstrated that it is possible to decrease or completely suppress the adsorption of proteins on the nanotube sidewall by using proper functionalization (either covalent or noncovalent). By subsequently activating the functional groups on the nanotube derivatives, protein adsorption can be recovered and, therefore, controlled. Our approach is simple, straightforward, and potentially suitable for other biomolecules that contain thio or amino groups available for coupling.     

Magnetic-fluorescent nanocomposites for biomedical multitasking

Fluorescent magnetite nanocomposites based on magnetic nanoparticles, a polyhedral octaaminopropylsilsesquioxane and a porphyrin derivative have been prepared. The intracellular uptake of the nanocomposites by macrophage and bone osteoblast cells, and their potential as MRI contrast agents, has been demonstrated.     

Many particle magnetic dipole-dipole and hydrodynamic interactions in magnetizable stent assisted magnetic drug targeting

The implant assisted magnetic targeted drug delivery system of Avilés, Ebner and Ritter is considered both experimentally (in vitro) and theoretically. The results of a 2D mathematical model are compared with 3D experimental results for a magnetizable wire stent. In this experiment a ferromagnetic, coiled wire stent is implanted to aid collection of particles which consist of single domain magnetic nanoparticles (radius ). In order to model the agglomeration of particles known to occur in this system, the magnetic dipole-dipole and hydrodynamic interactions for multiple particles are included. Simulations based on this mathematical model were performed using open source C++ code. Different initial positions are considered and the system performance is assessed in terms of collection efficiency. The results of this model show closer agreement with the measured in vitro experimental results and with the literature. The implications in nanotechnology and nanomedicine are based on the prediction of the particle efficiency, in conjunction with the magnetizable stent, for targeted drug delivery.     

High content analysis of the biocompatibility of nickel nanowires

Nickel nanowires, 20 μm long and 200 nm in diameter, were fabricated by electrodeposition into alumina templates, and characterised by superconducting quantum interference device (SQUID) magnetometer, X-ray diffraction and scanning electron microscopy. Biocompatibility studies of nickel nanowires with differentiated THP-1 cell line-derived macrophages were carried out. From a multiparametric assay, using high content analysis (HCA), the critical time points and concentrations of nickel nanowires on THP-1 cellular response were identified. The nanowires displayed little or no toxic effects on THP-1 cells over short incubation times (10 h), and at low concentrations (<100 nanowires per cell). Our findings indicate the potential suitability of these wires for biological and clinical applications.     

Xanthene Dyes and Green LED for the Inactivation of Foodborne Pathogens in Planktonic and Biofilm States

This study evaluated the rose bengal‐ and erythrosine‐mediated photoinactivation against Salmonella Typhimurium and Staphylococcus aureus planktonic and sessile cells using green LED as a light source. The free‐living or 2‐day‐old biofilm cells were treated with different concentrations of the photosensitizing agents and subjected to irradiation. Only 5 min photosensitization with rose bengal at 25 nmol L^?1 and 75 μmol L^?1 completely eliminated S. aureus and S. Typhimurium planktonic cells, respectively. Erythrosine at 500 nmol L^?1 and 5 min of light exposure also reduced S. aureus planktonic cells to undetectable levels. Eradication of S. aureus biofilms was achieved when 500 μmol L^?1 of erythrosine or 250 μmol L^?1 of rose bengal was combined with 30 min of irradiation. Scanning electron microscopy allowed the observation of morphological changes in planktonic cells and disruption of the biofilm architecture after photodynamic treatment. The overall data demonstrate that rose bengal and erythrosine activated by green LED may be a targeted strategy for controlling foodborne pathogens in both planktonic and sessile states.     

Analysis of platelet function: role of microfluidics and nanodevices

Platelet aggregation is essential for vascular haemostasis and thrombosis. To improve the therapy of arterial thrombotic disorders and identify novel therapeutic targets it is imperative to study basic mechanisms of platelet thrombus formation. To date most data on biology, physiology and pharmacology of platelet aggregation have been obtained by studying this phenomenon under static or quasi-dynamic conditions at the macroscale level. There is a widespread recognition for the need of new technologies that will help to further elucidate the role of platelets in physiological and pathological thrombus formation and to design more effective and specific antithrombotic drugs. Micro- and nanofluidic devices, capable of reaching nanoscale resolution, can be used for this purpose setting the scene for the development of novel methods for studying platelet function in physiology, pathology and therapeutics.     

Theoretical modelling of physiologically stretched vessel in magnetisable stent assisted magnetic drug targetingapplication

The magnetisable stent assisted magnetic targeted drug delivery system in a physiologically stretched vessel is considered theoretically. The changes in the mechanical behaviour of the vessel are analysed under the influence of mechanical forces generated by blood pressure. In this 2D mathematical model a ferromagnetic, coiled wire stent is implanted to aid collection of magnetic drug carrier particles in an elastic tube, which has similar mechanical properties to the blood vessel. A cyclic mechanical force is applied to the elastic tube to mimic the mechanical stress and strain of both the stent and vessel while in the body due to pulsatile blood circulation. The magnetic dipole–dipole and hydrodynamic interactions for multiple particles are included and agglomeration of particles is also modelled. The resulting collection efficiency of the mathematical model shows that the system performance can decrease by as much as 10% due to the effects of the pulsatile blood circulation.