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Ultrasmall water-soluble silver nanoclusters are synthesized, and their properties are investigated. The silver nanoclusters have high colloidal stability and show fluorescence in the red. This demonstrates that like gold nanoclusters also silver nanoclusters can be fluorescent.

Among various hybrid nanomaterials, the combination of plasmonic nanoparticles and fluorophores in a single multifunctional nanoplatform, so‐called plasmophores, has attracted significant attention in different fields such as dark field, fluorescence, and photoacoustic imaging, biosensing, photothermal, and photodynamic therapy. Herein, author report a facile and controlled synthesis route of hybrid nanoplatforms composed of fluorescent gold nanoclusters (GNCs) coupled to plasmonic gold nanorods (GNRs) using controlled silica (SiO2) dielectric spacers of different thicknesses from now on referred to as GNR@SiO2@GNC plasmophores. The results show different degrees of plasmon‐enhanced fluorescence of the GNCs in their plasmophore hybrid system when placed at different distances from the plasmonic cores of the GNRs. On the other hand, these plasmophores show enhanced thermal stability compared to GNRs@CTAB (CTAB, cetyl trimethyl ammonium bromide). This results also demonstrated that upon annealing at elevated temperatures (800–1000 °C), the GNRs in the plasmophores are more thermally stable and robust than the GNRs@CTAB. More surprisingly, despite the commonly reported very low melting temperature of smaller‐size nanocrystals, the GNCs in the plasmophores showed high thermal stability and do not exhibit significant structural changes at elevated temperatures (800–1000 °C). [ABSTRACT FROM AUTHOR]

11-Mercaptoundecanoic acid-protected gold nanoclusters (Au@MUA NCs) were synthesized and investigated as a model to understand the photoluminescence (PL) properties of water-soluble, structurally unknown Au NCs. Surface engineering, including ligand exchange where the length of the alkane chain was changed, ligand conjugation where the charged terminal carboxyl group of the ligands was blocked, and effects of external chemical reducing and oxidizing agents, was carried out. PL profiles were monitored to reveal the impact of surface engineering on the PL. We found that surface ligands, especially the ligand's length and ligand functionalities, play a significant role in the PL properties of Au@MUA NCs. The results also show interesting properties of these NCs as a tunable PL sensor. [ABSTRACT FROM AUTHOR]

Abstract: Fluorescent molecular markers were encapsulated. The capsules were additionally modified with plasmonic nanoparticles. The encapsulated markers were endocytosed by cells. Upon light stimulation the plasmonic nanoparticles generated heat, which opened the encapsulation and transiently perforated the endosomal/lysosomal membrane surrounding the capsule, thus allowing for release of the marker into the cytosol. Fluorescence labeling of different intracellular compartments was demonstrated in this way. Most important, the cells do not need to be fixed and perforated, as the molecular markers are introduced into cells by endocytosis and subsequent light‐induced release. Thus this technique allows for intracellular fluorescence labeling of living cells. [ABSTRACT FROM AUTHOR]

The synthesis of microcapsules consisting of DNA shells crosslinked by anti-VEGF (vascular epithelial growth factor) or anti-ATP (adenosine triphosphate) aptamers and loaded with tetramethylrhodamine-modified dextran, TMR-D, and Texas Red-modified dextran, TR-D, respectively, as fluorescence labels acting as models for drug loads, is described. The aptamer-functionalized microcapsules act as stimuli-responsive carriers for the triggered release of the fluorescent labels in the presence of the overexpressed cancer cell biomarkers VEGF or ATP. The VEGF- and ATP-responsive microcapsules are, also, loaded with the anticancer drug doxorubicin (DOX), in the form of DOX-functionalized dextran, DOX-D. The release of DOX-D from the respective microcapsules proceeds in the presence of VEGF or ATP as triggers. Preliminary cell experiments reveal that the ATP-responsive DOX-D-loaded microcapsules undergo effective endocytosis into MDA-MB-231 cancer cells. The ATP-responsive DOX-D-loaded microcapsules incorporated into the MDA-MB-231 cancer cells reveal impressive cytotoxicity as compared to normal epithelial MCF-10A breast cells (50% vs 0% cell death after 24 h, respectively). The cytotoxicity of the ATP-responsive DOX-D-loaded microcapsules toward the cancer cells is attributed to the effective unlocking of the microcapsules by overexpressed ATP, and to the subsequent release of DOX from the dextran backbone under acidic conditions present in cancer cells (pH = 6.2). [ABSTRACT FROM AUTHOR]

Abstract: Colloidal semiconductor nanoparticles (quantum dots) have attracted a lot of interest in technological and biomedical research, given their potent fluorescent properties. However, the use of heavy-metal-containing nanoparticles remains an issue of debate. The possible toxic effects of quantum dots remain a hot research topic and several questions such as possible intracellular degradation of quantum dots and the effect thereof on both cell viability and particle functionality remain unresolved. In the present work, poly(methacrylic acid)-coated CdSe/ZnS quantum dots were synthesized and characterized, after which their effects on cultured cells were evaluated using a multiparametric setup. The data reveal that the quantum dots are taken up through endocytosis and when exposed to the low pH of the endosomal structures, they partially degrade and release cadmium ions, which lowers their fluorescence intensity and augments particle toxicity. Using the multiparametric method, the quantum dots were evaluated at non-toxic doses in terms of their ability to visualize labeled cells for longer time periods. The data revealed that comparing different particles in terms of their applied dose is challenging, likely due to difficulties in obtaining accurate nanoparticle concentrations, but evaluating particle toxicity in terms of their biological functionality enables an easy and straightforward comparison. [Copyright &y& Elsevier]

Besides the typical short-lived fluorescence with decay times in the nanosecond range, colloidal II/VI semiconductor nanoparticles dispersed in buffer also possess a long-lived fluorescence component with decay times in the microsecond range. Here, the signal intensity of the long-lived luminescence at microsecond range is shown to increase 1,000-fold for CdTe nanoparticles in PBS buffer. This long-lived fluorescence can be conveniently employed for time-gated fluorescence detection, which allows for improved signal-to-noise ratio and thus the use of low concentrations of nanoparticles. The detection principle is demonstrated with a time-resolved fluorescence immunoassay for the detection of C-reactive protein (CRP) using CdSe-ZnS nanoparticles and green light excitation. [ABSTRACT FROM AUTHOR]

Summary: A protocol is described which allows the quantification of cells belonging to one type within a coculture of two cell types. For this, a series of micrographs recorded under different conditions (transmission, different fluorescence wavelength) were processed using an image recognition software. To show the effectiveness of the protocol, the relative amounts of adherent cells in three different cocultures of two cell types were determined as a function of the chemical patterning of substrates. [ABSTRACT FROM AUTHOR]

It is now known that nanoparticles, when exposed to biological fluid, become coated with proteins and other biomolecules to form a ‘protein corona’. Recent systematic studies have identified various proteins that can make up this corona, but these nanoparticle–protein interactions are still poorly understood, and quantitative studies to characterize them are few in number. Here, we have quantitatively analysed the adsorption of human serum albumin onto small (10–20 nm in diameter) polymer-coated FePt and CdSe/ZnS nanoparticles by using fluorescence correlation spectroscopy. The protein corona forms a monolayer with a thickness of 3.3 nm. Proteins bind to the negatively charged nanoparticles with micromolar affinity, and time-resolved fluorescence quenching experiments show that they reside on the particle for ∼100 s. These new findings deepen our quantitative understanding of the protein corona, which is of utmost importance in the safe application of nanoscale objects in living organisms. [ABSTRACT FROM AUTHOR]

The authors apologized for the unfortunate error in figure during publication of the article and they also explained that some of the solid grey graphs in Fig. 5 are intentionally based on the same data. For 8 different surface makers (CD14, CD73, CD34, CD105, CD19, CD90, CD45, HA-DR) in accordance to the guidelines of the manufacturer a panel of 4 different isotype controls were used, corresponding to 4 different fluorescence channels. [ABSTRACT FROM AUTHOR]

Adenosine triphosphate (ATP)–responsive DNA‐based microcapsules loaded with the chemotherapeutic doxorubicin drug are synthesized and incorporated into cancer cells. I. Willner and co‐workers find, on page 4262, that over‐expressed ATP in cancer cells dissociates the microcapsules and releases the drug, resulting in selective cytotoxicity toward cancer cells. [ABSTRACT FROM AUTHOR]

Particle-based fluorescence sensors for the quantification of specific ions can be made by coupling ion-sensitive fluorophores to carrier particles, or by using intrinsically fluorescent particles whose fluorescence properties depend on the concentration of the ions. Despite the advantages of such particle-based sensors for the quantitative detection of ions, such as the possibility to tune the surface chemistry and thus entry portal of the sensor particles to cells, they have also some associated problems. Problems involve for example crosstalk of the ion-sensitive fluorescence read-out with pH, or spectral overlap of the emission spectra of different fluorescent particles in multiplexing formats. Here the benefits of using particle-based fluorescence sensors, their limitations and strategies to overcome these limitations will be described and exemplified with selected examples. [ABSTRACT FROM AUTHOR]