Quantum-Dot-Based Iron Oxide Nanoparticles Activate the NLRP3 Inflammasome in Murine Bone Marrow-Derived Dendritic Cells.

Inflammasomes are cytosolic complexes composed of a Nod-like receptor, NLR, the adaptor protein, ASC, and a proteolytic enzyme, caspase-1. Inflammasome activation leads to caspase-1 activation and promotes functional maturation of IL-1ß and IL-18, two prototypical inflammatory cytokines. Besides, inflammasome activation leads to pyroptosis, an inflammatory type of cell death. Inflammasomes are vital for the host to cope with foreign pathogens or tissue damage. Herein, we show that quantum-dot-based iron oxide nanoparticles, MNP@QD, trigger NLRP3 inflammasome activation and subsequent release of proinflammatory interleukin IL-1ß by murine bone marrow-derived dendritic cells (BMDCs). This activation is more pronounced if these cells endocytose the nanoparticles before receiving inflammatory stimulation. MNP@QD was characterized by using imaging techniques like transmission electron microscopy, fluorescence microscopy, and atomic force microscopy, as well as physical and spectroscopical techniques such as fluorescence spectroscopy and powder diffraction. These findings may open the possibility of using the composite MNP@QD as both an imaging and a therapeutic tool.

Unravelling the nature of the spongy dark material in aged Turkevich gold nanoparticles colloidal solutions by CytoViva® dark-field imaging and HRTEM analysis.

Turkevich gold nanoparticles colloidal solutions undergo further changes after ageing for several weeks or months, and in most cases a spongy dark material can be observed suspended in the red solution. CytoViva® dark-field microscopy images and high resolution transmission electron micrographys (HRTEM) of the strange body played a central role and revealed a fibrous structure, consistent with cellulose, as commonly found in the cell-walls of many fungi. Surprisingly, the interior of the fibers are filled with gold nanoparticles, responsible for the high contrasting images obtained in this work. The fungi were replicated in the laboratory, characterized by Infrared Microscopy (FTIR) and revealed an ability to grow in gold-citrate media, even in dark and anaerobical conditions.

A new ferrous diflunisal complex and its effects on biopools of labile iron.

Drugs bearing metal-coordinating moieties can alter biological metal distribution. In this work, a complex between iron(II) and diflunisal was prepared in the solid state, exhibiting the following composition: [Fe(diflunisal)2(H2O)2], (Fe(dif)2). The ability of diflunisal to alter labile pools of both plasmatic and cellular iron was investigated in this work. We found out that diflunisal does not increase the levels of redox-active iron in plasma of iron overloaded patients. However, diflunisal efficiently carries iron into HeLa or HepG2 cells, inducing an iron-catalyzed oxidative stress.

One-pot single step to label microtubule with MPA-capped CdTe quantum dots.

The kinesin-microtubule pair has attracted much attention in recent years due to their promising use in the development of synthetic nanotransport machines. One of the challenges to study such system is how to observe the motility of either kinesin or microtubule. The usual technique for observation of the molecular machinery pair is by fluorescence microscopy, where fluorescent probes are bound to one, or both species, through a biotin-avidin linker. Here, the use of mercaptopropionic acid (MPA)-capped cadmium telluride (CdTe) quantum dots (QDs) as a direct fluorescent labeling agent to microtubule biomolecules is reported. QDs are able to not only bind to microtubules in vitro, but also to fluorescently label them in the red spectral region. Surface plasmon resonance (SPR) studies showed the binding of synthesized QDs to microtubules, while quantum dots-labeled microtubules were successfully visualized with fluorescence microscopy. It is believed QDs adsorbs to the microtubule surface mainly through the coordination of Cd with histidine, cysteine and methionine residues, as well as through interactions of the nanocrystal's carboxylated surface with free amino groups on microtubules.