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A combinatorial screening revealed the peptide H-His- d-Leu- d-Asp-NH2 ( 1) as an additive for the generation of monodisperse, water-soluble palladium nanoparticles with average diameters of 3 nm and stabilities of over 9 months. The tripeptide proved to be also applicable for the size-controlled formation of other noble-metal nanoparticles (Pt and Au). Studies with close analogues of peptide 1 revealed a specific role of each of the three amino acids for the formation and stabilization of the nanoparticles. These data combined with microscopic and spectroscopic analyses provided insight into the structure of the self-assembled peptidic monolayer around the metal core. The results open interesting prospects for the development of functionalized metal nanoparticles. [ABSTRACT FROM AUTHOR]

Nanoparticles covered with ligand shells comprising both positively and negatively charged ligands exhibit Gram-selective antibacterial action controlled by a single experimental parameter, namely the proportion of [+] and [−] ligands tethered onto these particles. Gram selectivity is attributed to the interplay between polyvalent electrostatic and non-covalent interactions that work in unison to disrupt the bacterial cell wall. The [+/−] nanoparticles are effective in low doses, are non-toxic to mammalian cells, and are tolerated well in mice. These results constitute the first example of rational engineering of Gram selectivity at the (macro)molecular level. [ABSTRACT FROM AUTHOR]

The development of high performance lubricants has been driven by increasingly growing industrial demands and environmental concerns. Herein, we demonstrate oil-soluble polymer brush-grafted inorganic nanoparticles (hairy NPs) as highly effective lubricant additives for friction and wear reduction. A series of oil-miscible poly(lauryl methacrylate) brush-grafted silica and titania NPs were synthesized by surface-initiated atom transfer radical polymerization. These hairy NPs showed exceptional stability in poly(alphaolefin) (PAO) base oil; no change in transparency was observed after being kept at −20, 22, and 100 °C for ≥55 days. High-contact stress ball-on-flat reciprocating sliding tribological tests at 100 °C showed that addition of 1 wt % of hairy NPs into PAO led to significant reductions in coefficient of friction (up to ≈40 %) and wear volume (up to ≈90 %). The excellent lubricating properties of hairy NPs were further elucidated by the characterization of the tribofilm formed on the flat. These hairy NPs represent a new type of lubricating oil additives with high efficiency in friction and wear reduction. [ABSTRACT FROM AUTHOR]

Cooperative catalysts consisting of chiral Rh/Ag nanoparticles and Sc(OTf)3 have been developed that catalyze asymmetric 1,4-addition reactions of arylboronic acids with α,α-unsaturated amides efficiently. The reaction has been considered one of the most challenging reactions because of the low reactivity of the amide substrates. The new catalysts provide the desired products with outstanding enantioselectivities (>98% ee) in the presence of low loadings (<0.5 mol%) of the catalyst. [ABSTRACT FROM AUTHOR]

The precise functionalization of self-assembled nanostructures with spatial and stereocontrol is a major objective of nanotechnology and holds great promise for many applications. Herein, the nanoscale addressability of DNA origami was exploited to develop a precise copymachine- like platform that can transfer two-dimensional oligonucleotide patterns onto the surface of gold nanoparticles (AuNPs) through a deliberately designed toehold-initiated DNA displacement reaction. This strategy of DNA-origamibased nanoimprinting lithography (DONIL) demonstrates high precision in controlling the valence and valence angles of AuNPs. These DNA-decorated AuNPs act as precursors in the construction of discrete AuNP clusters with desired chirality. [ABSTRACT FROM AUTHOR]

Using the example of carbon nanoparticles of different functionality and shape, the possibilities of a comprehensive surface characterization are presented. In the focus of the analytical work lie electrokinetic and wetting measurements, which were supplemented by X-ray photoelectron spectroscopy and gas sorption measurements. Thus, the chemical functionality, the surface energy as well as the topography of the particle surfaces can be described quantitatively. Knowing these variables allows a targeted selection of particles as reinforcing materials as well as nucleating agents. [ABSTRACT FROM AUTHOR]

Surface wettability of active sites plays a crucial role in the activity and selectivity of catalysts. This report describes modification of surface hydrophobicity of Pd/UiO-66, a composite comprising a metal-organic framework (MOF) and stabilized palladium nanoparticles (NPs), using a simple polydimethylsiloxane (PDMS) coating. The modified catalyst demonstrated significantly improved catalytic efficiency. The approach can be extended to various Pd nanoparticulate catalysts for enhanced activity in reactions involving hydrophobic reactants, as the hydrophobic surface facilitates the enrichment of hydrophobic substrates around the catalytic site. PDMS encapsulation of Pd NPs prevents aggregation of NPs and thus results in superior catalytic recyclability. Additionally, PDMS coating is applicable to a diverse range of catalysts, endowing them with additional selectivity in sieving reactants with different wettability. [ABSTRACT FROM AUTHOR]

Despite the high potency of bilirubin as an endogenous anti-inflammatory compound, its clinical translation has been hampered because of its insolubility in water. Bilirubin-based nanoparticles that may overcome this critical issue are presented. A polyethylene glycol compound (PEG) was covalently attached to bilirubin, yielding PEGylated bilirubin (PEG-BR). The PEG-BR self-assembled into nanoscale particles with a size of approximately 110 nm, termed bilirubin nanoparticles (BRNPs). BRNPs are highly efficient hydrogen peroxide scavengers, thereby protecting cells from H2O2-induced cytotoxicity. In a murine model of ulcerative colitis, intravenous injection of BRNPs showed preferential accumulation of nanoparticles at the sites of inflammation and significantly inhibited the progression of acute inflammation in the colon. Taken together, BRNPs show potential for use as a therapeutic nanomedicine in various inflammatory diseases. [ABSTRACT FROM AUTHOR]

RNA interference (RNAi) gene silencing technologies have shown significant potential for treating various diseases, including cancer. However, clinical success in cancer therapy remains elusive, mainly owing to suboptimal in vivo delivery of RNAi therapeutics such as small interference RNA (siRNA) to tumors. Herein, we developed a library of polymers that respond to a narrow pH change (ultra-pH-responsive), and demonstrated the utility of these materials in targeted and deep tumor-penetrating nanoparticle (NP) for in vivo RNAi. The new NP platform is mainly composed of the following key components: i) internalizing RGD (iRGD) to enhance tumor targeting and tissue penetration; ii) polyethylene glycol (PEG) chains to prolong blood circulation; and iii) sharp pH-responsive hydrophobic polymer to improve endosome escape. Through systematic studies of structure-function relationship, the optimized RNAi NPs (<70 nm) showed efficient gene silencing and significant inhibition of tumor growth with negligible toxicities in vivo. [ABSTRACT FROM AUTHOR]

Die zunehmende Produktion und Verwendung von Nanopartikeln erfordert eine höchst empfindliche analytische Methode für die Quantifizierung und Identifizierung dieser potenziell gefährlichen Materialien. Hier beschreiben wir eine Anwendung der Oberflächenplasmonen ‐ Mikroskopie für den Einzelnachweis jedes einzelnen adsorbierten Nanopartikels und die Sichtbarmachung seiner elektrochemischen Umsetzung. Während die Adsorptionsgeschwindigkeit die Mengenkonzentration der Nanopartikel charakterisiert, bestimmt das Oxidationspotential, bei dem die adsorbierten Nanopartikel optisch verschwinden, die Art ihres Materials. Alle adsorbierten Nanopartikel unterliegen zeitgleich dem Potentialvorschub, werden aber mithilfe ihres elektrochemischen Auflösungspotentials von einem einzelnen bis zu einer Million adsorbierter Partikel individuell identifiziert. Mit dieser Technik wurden Silber ‐ und Kupfernanopartikel untersucht, sie kann aber auch auf viele andere elektrochemisch aktive Nanopartikel übertragen werden. Die Detektion einzelner Nanopartikel (NPs) und die Visualisierung ihrer elektrochemischen Umwandlung auf der Sensoroberfläche sind durch Oberflächenplasmonen ‐ Mikroskopie möglich. Während die Adsorptionsgeschwindigkeit Auskunft über die NP ‐ Konzentration gibt, charakterisiert das Potential, bei dem die adsorbierten NPs während des anodischen Potentialvorschubs verschwinden, ihre chemische Zusammensetzung. Dabei wird jedes adsorbierte NP individuell identifiziert. [ABSTRACT FROM AUTHOR]

Development of a photosensitizing system that can reversibly control the generation of singlet oxygen (1O2) is of great interest for photodynamic therapy (PDT). Recently several photosensitizer-photochromic-switch dyads were reported as a potential means of the 1O2 control in PDT. However, the delivery of such a homogeneous molecular dyad as designed (e.g., optimal molar ratio) is extremely challenging in living systems. Herein we show a Zr-MOF nanoplatform, demonstrating energy transfer-based 1O2 controlled PDT. Our strategy allows for tuning the ratios between photosensitizer and the switch molecule, enabling maximum control of 1O2 generation. Meanwhile, the MOF provides proximal placement of the functional entities for efficient intermolecular energy transfer. As a result, the MOF nanoparticle formulation showed enhanced PDT efficacy with superior 1O2 control compared to that of homogeneous molecular analogues. [ABSTRACT FROM AUTHOR]

A highly active alternative to Pt electrocatalysts for the oxygen reduction reaction (ORR), which is the cathode-electrode reaction of fuel cells, is sought for higher fuel-cell performance. Our theoretical modelling reveals that B-doped Pd (Pd-B) weakens the absorption of ORR intermediates with nearly optimal binding energy by lowering the barrier associated with O2 dissociation, suggesting Pd-B should be highly active for ORR. In fact, Pd-B, facile synthesized by an electroless deposition process, exhibits 2.2 times and 8.8 times higher specific activity and 14 times and 35 times less costly than commercial pure Pd and Pt catalysts, respectively. Another computational result is that the surface core level of Pd is negatively shifted by B doping, as confirmed by XPS, and implies that filling the density of states related to the anti-bonding of oxygen to Pd surfaces with excess electrons from B doping, weakens the O bonding to Pd and boosts the catalytic activity. [ABSTRACT FROM AUTHOR]

Copyright of Der Ophthalmologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The fragile nature of most enzymes is a major hindrance to their use in industrial processes. Herein, we describe a synthetic chemical strategy to produce hybrid organic/inorganic nanobiocatalysts; it exploits the self-assembly of silane building blocks at the surface of enzymes to grow an organosilica layer, of controlled thickness, that fully shields the enzyme. Remarkably, the enzyme triggers a rearrangement of this organosilica layer into a significantly soft structure. We demonstrate that this change in stiffness correlates with the biocatalytic turnover rate, and that the organosilica layer shields the enzyme in a soft environment with a markedly enhanced resistance to denaturing stresses. [ABSTRACT FROM AUTHOR]

The discovery and synthesis of novel multifunctional organic building blocks for nanoparticles is challenging. Texaphyrin macrocycles are capable and multifunctional chelators. However, they remain elusive as building blocks for nanoparticles because of the difficulty associated with synthesis of texaphyrin constructs capable of self-assembly. A novel manganese (Mn)-texaphyrin-phospholipid building block is described, along with its one-pot synthesis and self-assembly into a Mn-nanotexaphyrin. This nanoparticle possesses strong resilience to manganese dissociation, structural stability, in vivo bio-safety, and structure-dependent T1 and T2 relaxivities. Magnetic resonance imaging (MRI) contrast enhanced visualization of lymphatic drainage is demonstrated with respect to proximal lymph nodes on the head and neck VX-2 tumors of a rabbit. Synthesis of 17 additional metallo-texaphyrin building blocks suggests that this novel one-pot synthetic procedure for nanotexaphyrins may lead to a wide range of applications in the field of nanomedicines. [ABSTRACT FROM AUTHOR]

Nanoparticles sized tens of nm with not only a highly complex but also a highly regular nanostructure, although ubiquitous in nature, are very difficult to prepare artificially. Herein, we report efficient solution-based preparation of narrow-disperse ABC three-segment hierarchical nanoparticles (HNPs) with a size of tens of nm through a three-level hierarchical self-assembly of A- b-B- b-C triblock copolymers in solution. An ABC HNP is composed of three nanoparticles, A, B, and C that are linearly connected; in the ABC HNP, the B nanoparticle is sandwiched between the A and C nanoparticles. The method for the preparation is highly efficient, because all of the A- b-B- b-C chains in the solution are converted into the ABC HNPs. Furthermore, the ABC HNPs self-assembled into Θ-shaped HNPs tens nm in size. Both the ABC and Θ-shaped HNPs, are highly complex but highly regular, and are novel HNPs, and they should be very promising for addressing various theoretical and practical problems. [ABSTRACT FROM AUTHOR]

Die Synthese von vier zweizähnigen NHC ‐ Thioether ‐ Hybridliganden wird vorgestellt. Mit diesen Liganden modifizierte Palladium ‐ Nanopartikel sind, in Abhängigkeit des verwendeten Liganden, in verschiedenen Lösungsmitteln stabil und zeigen eine hohe Chemoselektivität in der Hydrierung von Olefinen. Die Löslichkeit der Nanopartikel konnte je nach pH ‐ Wert des Lösungsmittels mehrfach geschaltet werden. Röntgen ‐ Photoelektronenspektroskopie (die eine feine Verschiebung in der Bindungsenergie zeigt) wurde als praktische Analysemethode zur Bestimmung des Bindungsmodus des NHC ‐ Liganden identifiziert. Wie Du willst! Zweizähnige NHC ‐ Thioether ‐ Hybridliganden zur Stabilisierung von Palladium ‐ Nanopartikeln (PdNPs) werden vorgestellt. Der modulare Ansatz ermöglicht die schnelle und leichte Synthese diverser Liganden je nach Lösungsmittel. Mithilfe von XPS wurde der Bindungsmodus des NHCs auf dem Nanopartikel bestimmt, und die katalytische Aktivität der Nanopartikel in der chemoselektiven Hydrierung wurde untersucht. [ABSTRACT FROM AUTHOR]

Copyright of Wiener Medizinische Wochenschrift is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Herein, we report an epitaxial-growth-mediated method to grow face-centered cubic (fcc) Ru, which is thermodynamically unfavorable in the bulk form, on the surface of Pd-Cu alloy. Induced by the galvanic replacement between Ru and Pd-Cu alloy, a shape transformation from a Pd-Cu@Ru core-shell to a yolk-shell structure was observed during the epitaxial growth. The successful coating of the unconventional crystallographic structure is critically dependent on the moderate lattice mismatch between the fcc Ru overlayer and PdCu3 alloy substrate. Further, both fcc and hexagonal close packed (hcp) Ru can be selectively grown through varying the lattice spacing of the Pd-Cu substrate. The presented findings provide a new synthetic pathway to control the crystallographic structure of metal nanomaterials. [ABSTRACT FROM AUTHOR]

One of the major drawbacks of organic-dye-modified self-assembled monolayers on metal nanoparticles when employed for efficient use of light energy is the fact that singlet excited states on dye molecules can be easily deactivated by means of energy transfer to the metal surface. In this study, a series of 6,13-bis(triisopropylsilylethynyl)pentacene-alkanethiolate monolayer protected gold nanoparticles with different particle sizes and alkane chain lengths were successfully synthesized and were employed for the efficient generation of excited triplet states of the pentacene derivatives by singlet fission. Time-resolved transient absorption measurements revealed the formation of excited triplet states in high yield (172±26 %) by suppressing energy transfer to the gold surface. [ABSTRACT FROM AUTHOR]

This work develops a site-specific duplexed luminescence resonance energy transfer system on cell surface for simultaneous imaging of two kinds of monosaccharides on a specific protein by single near-infrared excitation. The single excitation-duplexed imaging system utilizes aptamer modified upconversion luminescent nanoparticles as an energy donor to target the protein, and two fluorescent dye acceptors to tag two kinds of cell surface monosaccharides by a dual metabolic labeling technique. Upon excitation at 980 nm, only the dyes linked to protein-specific glycans can be lit up by the donor by two parallel energy transfer processes, for in situ duplexed imaging of glycoforms on specific protein. Using MUC1 as the model, this strategy can visualize distinct glycoforms of MUC1 on various cell types and quantitatively track terminal monosaccharide pattern. This approach provides a versatile platform for profiling protein-specific glycoforms, thus contributing to the study of the regulation mechanisms of protein functions by glycosylation. [ABSTRACT FROM AUTHOR]

The biodegradable inorganic nanovector based on a layered double hydroxide (LDH) holds great promise for gene and drug delivery systems. However, in vivo targeted delivery of genes through LDH still remains a key challenge in the development of RNA interference therapeutics. Here, we describe in vivo and in vitro delivery system for Survivin siRNA (siSurvivin) assembled with passive LDH with a particle size of 100 nm or active LDH conjugated with a cancer overexpressing receptor targeting ligand, folic acid (LDHFA), conferring them an ability to target the tumor by either EPR-based clathrin-mediated or folate receptor-mediated endocytosis. When not only transfected into KB cells but also injected into xenograft mice, LDHFA/siSurvivin induced potent gene silencing at mRNA and protein levels in vitro, and consequently achieved a 3.0-fold higher suppression of tumor volume than LDH/siSurvivin in vivo. This anti-tumor effect was attributed to a selectively 1.2-fold higher accumulation of siSurvivin in tumor tissue compared with other organs. Targeting to the tumor with inorganic nanovector can guide and accelerate an evolution of next-generation theranosis system. [ABSTRACT FROM AUTHOR]

Nanomaterials have been widely used for applications in biomedical fields and could become indispensable in the near future. However, since it is difficult to optimize in vivo biological behavior in a 3D environment by using a single cell in vitro, there have been many failures in animal models. In vitro prediction systems using 3D human-tissue models reflecting the 3D location of cell types may be useful to better understand the biological characteristics of nanomaterials for optimization of their function. Herein we demonstrate the potential ability of 3D engineered human-arterial models for in vitro prediction of the in vivo behavior of nanoparticles for drug delivery. These models enabled optimization of the composition and size of the nanoparticles for targeting and treatment efficacy for atherosclerosis. In vivo experiments with atherosclerotic mice suggested excellent biological characteristics and potential treatment effects of the nanoparticles optimized in vitro. [ABSTRACT FROM AUTHOR]

Controlling or switching the optical signal from a large collection of molecules with the minimum of photons represents an extremely attractive concept. Promising fundamental and practical applications may be derived from such a photon-saving principle. With this aim in mind, we have prepared fluorescent photochromic organic nanoparticles (NPs), showing bright red emission, complete ON-OFF contrast with full reversibility, and excellent fatigue resistance. Most interestingly, upon successive UV and visible light irradiation, the NPs exhibit a complete fluorescence quenching and recovery at very low photochromic conversion levels (<5 %), leading to the fluorescence photoswitching of 420±20 molecules for only one converted photochromic molecule. This 'giant amplification of fluorescence photoswitching' originates from efficient intermolecular energy-transfer processes within the NPs. [ABSTRACT FROM AUTHOR]

Polymerization-induced self-assembly (PISA) was employed to compare the self-assembly of different amphiphilic block copolymers. They were obtained by emulsion polymerization of styrene in water using hydrophilic poly( N-acryloylmorpholine) (PNAM)-based macromolecular RAFT agents with different structures. An average of three poly (ethylene glycol acrylate) (PEGA) units were introduced either at the beginning, statistically, or at the end of a PNAM backbone, resulting in formation of nanometric vesicles and spheres from the two former macroRAFT architectures, and large vesicles from the latter. Compared to the spheres obtained with a pure PNAM macroRAFT agent, composite macroRAFT architectures promoted a dramatic morphological change. The change was induced by the presence of PEGA hydrophilic side-chains close to the hydrophobic polystyrene segment. [ABSTRACT FROM AUTHOR]

A molecular beacon-based drug delivery system was designed for both detection of telomerase activity in living cells and telomerase-triggered drug release for precise cancer treatment. This system is composed of a gold nanoparticle core densely packed with FITC-labeled hairpin DNA sequences hybridized with telomerase primers. Molecules of the anticancer drug doxorubicin were intercalated into the stem region of the DNA sequence. The presence of telomerase will elongate the primers, leading to inner chain substitution followed by the release of the FITC fluorescence and the trapped doxorubicin. This molecular beacon could specifically distinguish tumor cells and normal cells based on telomerase activity, precisely release doxorubicin in response to telomerase activity in the tumor cells, and prevent toxicity to normal organs. [ABSTRACT FROM AUTHOR]

Effective delivery of therapeutic proteins is a formidable challenge. Herein, using a unique polymer family with a wide-ranging set of cationic and hydrophobic features, we developed a novel nanoparticle (NP) platform capable of installing protein ligands on the particle surface and simultaneously carrying therapeutic proteins inside by a self-assembly procedure. The loaded therapeutic proteins (e.g., insulin) within the NPs exhibited sustained and tunable release, while the surface-coated protein ligands (e.g., transferrin) were demonstrated to alter the NP cellular behaviors. In vivo results revealed that the transferrin-coated NPs can effectively be transported across the intestinal epithelium for oral insulin delivery, leading to a notable hypoglycemic response. [ABSTRACT FROM AUTHOR]

A most important task in oncology today is the search for structures capable of specific targeting and inactivating the cancer stem cells determining the tumor growth. We describe the investigation of the ability of the synthesized hybrid nanocomplexes containing rare earth-based nanoparticles of GdYVO4 : Eu3+ orthovanadates, cholesterol and the hydrophobic luminescent dye DiI to visualize and inactivate the cancer stem cells of the Ehrlich carcinoma. The spectral analysis revealed an intracellular accumulation of nanoparticles in the Ehrlich carcinoma cells. This fact suggested the implementation of antitumor effect of the nanoparticles in vivo. The treatment of the Ehrlich carcinoma cells with spherical nanoparticles at a concentration of 1.30 g/L was found to reduce the intensity of tumor growth by 58.2 %. Ehrlich carcinoma cell processing with a three component hybrid complex resulted in a maximum decrease in the concentration of the most carcinogenic CD44hi cells with a simultaneous increase in the number of CD117+ cells, which reduced the intensity of tumor growth by 76.6 %. When applying hybrid nanocomplexes, a reduced expression rate of the oct4, sox2 and nanog genes in Ehrlich carcinoma cells was observed which may be a mechanism for the antitumor action of orthovanadates. [ABSTRACT FROM AUTHOR]

In this manuscript we describe the development of a hybrid organometallic coating to be used on glass surface. This coating consists of gold nanoparticles covered by difurylethene-based diarylethene (DAE) photochromic molecules which are investigated covalently bound on glass slides. Diarylethene being attached to the gold nanoparticles by thiol groups formed mainly disordered monolayer on the Au Np surface. Nanoparticles bearing the open-ring form of DAE showing an up to 6 % increased intensity of the absorption band maximum at λ = 520 nm compared to unmodified nanoparticles. This value was even increased to 22 % when the nanoparticles ware covered with a monolayer of the closed ring DAE, revealing a strong variation of the local refractive index of gold nanoparticles. Moreover, besides modification of the gold nanoparticles refractive index, the DAEs interacted most probably with the local surface plasmon resonance excitation. This was evident by a blue shift of the absorbance band of the long wave absorbance of the nanoparticles instead of the expected red shift. Simultaneously with the observed blue shift a strong increase of intensity of the visible light absorption was observed. The obtained results are discussed in view of the calculated values of visible-light absorbance of gold nanoparticles chemically attached to glass slides. [ABSTRACT FROM AUTHOR]

The amplification and digital quantification of single DNA molecules are important in biomedicine and diagnostics. Beyond quantifying DNA molecules in a sample, the ability to express proteins from the amplified DNA would open even broader applications in synthetic biology, directed evolution, and proteomics. Herein, a microfluidic approach is reported for the production of condensed DNA nanoparticles that can serve as efficient templates for in vitro protein synthesis. Using phi29 DNA polymerase and a multiple displacement amplification reaction, single DNA molecules were converted into DNA nanoparticles containing up to about 104 clonal gene copies of the starting template. DNA nanoparticle formation was triggered by accumulation of inorganic pyrophosphate (produced during DNA synthesis) and magnesium ions from the buffer. Transcription-translation reactions performed in vitro showed that individual DNA nanoparticles can serve as efficient templates for protein synthesis in vitro. [ABSTRACT FROM AUTHOR]

Surface plasmon resonances of metal nanoparticles have shown significant promise for the use of solar energy to drive catalytic chemical reactions. More importantly, understanding and monitoring such catalytic reactions at single-nanoparticle level is crucial for the study of local reaction processes. Herein, using plasmonic photoluminescence (PL) spectroscopy, we describe a novel sensing method for catalytic ethanol oxidation reactions at the single-nanoparticle level. The Au nanorod monitors the interfacial interaction with ethanol during the catalytic reaction through the PL intensity changes in the single-particle PL spectra. The analysis of energy relaxation of excited electron-hole pairs indicates the relationship between the PL quenching and ethanol oxidation reaction on the single Au nanorod. [ABSTRACT FROM AUTHOR]

As a 'silent killer', kidney disease is often hardly detected at an early stage but can cause lethal kidney failure later on. Thus, a preclinical imaging technique that can readily differentiate between the stages of kidney dysfunction is highly desired for improving our fundamental understanding of kidney disease progression. Herein, we report that in vivo fluorescence imaging, enabled by renal-clearable near-infrared-emitting gold nanoparticles, can noninvasively detect kidney dysfunction, report on the dysfunctional stages, and even reveal adaptive function in a mouse model of unilateral obstructive nephropathy, which cannot be diagnosed with routine kidney function markers. These results demonstrate that low-cost fluorescence kidney functional imaging is highly sensitive and useful for the longitudinal, noninvasive monitoring of kidney dysfunction progression in preclinical research. [ABSTRACT FROM AUTHOR]

Electroresponsive structurally colored materials composed of ordered arrays of polyaniline@poly(methyl methacrylate) (PANI@PMMA) core-shell nanoparticles have been successfully prepared. The core-shell nanoparticles were synthesized by deposition of PANI shells on the surfaces of the PMMA cores by the oxidative polymerization of anilinium chloride. Ordered arrays were then fabricated by using the fluidic cell method. Because the ordered arrays and the PANI shells generate structural and electrochromic colors, respectively, these core-shell colloidal crystals exhibited colors resulting from the combined effects of these materials. The crystal colors depended greatly on the size of PANI@PMMA particles and could also be varied by the application of a voltage. The electrochromic colors of these arrays were found to be quite different from those exhibited by pure PANI films prepared by electrochemical oxidation. [ABSTRACT FROM AUTHOR]

Lanthanide doped core-multishell structured NaGdF4:Yb,Er@NaYF4:Yb@NaGdF4:Yb,Nd@NaYF4@NaGdF4:Yb,Tm@NaYF4 nanoparticles with power-density independent orthogonal excitations-emissions upconversion luminescence (UCL) were fabricated for the first time. The optical properties of these core-multishell structured nanoparticles were related to the absorption filtration effect of the NaGdF4:Yb,Tm layer. By tuning the thickness of the filtration layer, the nanoparticles can exhibit unique two independent groups of UCL: Tm3+ prominent UV/blue (UV=ultraviolet) UCL under the excitation at 980 nm and Er3+ prominent green/red UCL under the excitation at 796 nm. The filtration-shell mediated orthogonal excitations-emissions UCL are power-density independent. As a proof of concept, the core-multishell nanoparticles are used in multi-dimensional security design and imaging-guided combined photodynamic therapy and chemotherapy. [ABSTRACT FROM AUTHOR]

A facile bottom-up approach to carbon nanodots (CNDs) is reported, using a microwave-assisted procedure under controlled conditions. The as-prepared nitrogen-doped CNDs (NCNDs) show narrow size-distribution, abundant surface traps and functional groups, resulting in tunable fluorescent emission and excellent solubility in water. Moreover, we present a general method for the separation of NCNDs by low-pressure size-exclusion chromatography, leading to an even narrower size distribution, different surface composition, and optical properties. They display among the smallest size and the highest FLQYs reported so far. 13C-enriched starting materials produced N13CNDs suitable for thorough NMR studies, which gave useful information on their molecular structure. Moreover, they can be easily functionalized and can be used as water-soluble carriers. This work provides an avenue to size- and surface-controllable and structurally defined NCNDs for applications in areas such as optoelectronics, biomedicine, and bioimaging. [ABSTRACT FROM AUTHOR]

The induction of antigen-specific adaptive immunity exclusively occurs in lymphoid organs. As a consequence, the efficacy by which vaccines reach these tissues strongly affects the efficacy of the vaccine. Here, we report the design of polymer hydrogel nanoparticles that efficiently target multiple immune cell subsets in the draining lymph nodes. Nanoparticles are fabricated by infiltrating mesoporous silica particles (ca. 200 nm) with poly(methacrylic acid) followed by disulfide-based crosslinking and template removal. PEGylation of these nanoparticles does not affect their cellular association in vitro, but dramatically improves their lymphatic drainage in vivo. The functional relevance of these observations is further illustrated by the increased priming of antigen-specific T cells. Our findings highlight the potential of engineered hydrogel nanoparticles for the lymphatic delivery of antigens and immune-modulating compounds. [ABSTRACT FROM AUTHOR]

Wir stellen eine neue Methode zur Herstellung sehr kleiner aufwärtskonvertierender Kern/Schale ‐ Nanokristalle vor, die ohne zusätzliche Kodotierung der Kernpartikel auskommt und Partikel im Gramm ‐ Maßstab liefert. Durch die Reaktion von Natriumoleat, Seltenerdoleat und Ammoniumfluorid werden zunächst ca. 5 nm große β ‐ NaYF4:Yb,Er ‐ Kernpartikel gebildet, wobei ein hohes Verhältnis von Natrium ‐ zu Seltenerdionen die Nukleation einer großen Anzahl von Keimen der β ‐ Phase begünstigt. Anschließend wird eine ca. 2 nm dicke Schale aus β ‐ NaYF4 aufgewachsen, wobei 3 – 4 nm große α ‐ NaYF4 ‐ Partikel als Vorläuferpartikel für das Schalenmaterial dienen. Im Gegensatz zu den Kernpartikeln werden diese Partikel der α ‐ Phase jedoch mit einem geringen Verhältnis von Natrium ‐ zu Seltenerdionen hergestellt, welches die unerwünschte Nukleation von β ‐ NaYF4 ‐ Partikeln während des Schalenwachstums wirksam unterdrückt. Kleine Größe: Nanopartikel der kubischen α ‐ Phase von NaYF4:Yb,Er und NaYF4 wurden für die Synthese sehr kleiner aufwärtskonvertierender β ‐ NaYF4: Yb,Er/NaYF4 ‐ Kern/Schale ‐ Partikel eingesetzt. Die Nukleation kann dabei so gesteuert werden, dass der Durchmesser der β ‐ NaYF4:Yb,Er ‐ Kernpartikel auf nur 5 nm beschränkt bleibt und gleichzeitig die unerwünschte Nukleation von β ‐ Partikeln aus reinem NaYF4 ‐ Schalenmaterial beim Schalenwachstum unterdrückt wird. [ABSTRACT FROM AUTHOR]

Successful bench-to-bedside translation of nanomedicine relies heavily on the development of nanocarriers with superior therapeutic efficacy and high biocompatibility. However, the optimal strategy for improving one aspect often conflicts with the other. Herein, we report a tactic of designing tumor-pH-labile linkage-bridged copolymers of clinically validated poly(D,L-lactide) and poly(ethylene glycol) (PEGDlinkm- PDLLA) for safe and effective drug delivery. Upon arriving at the tumor site, PEG-Dlinkm-PDLLA nanoparticles will lose the PEG layer and increase zeta potential by responding to tumor acidity, which significantly enhances cellular uptake and improves the in vivo tumor inhibition rate to 78.1% in comparison to 47.8% of the non-responsive control. Furthermore, PEG-Dlinkm-PDLLA nanoparticles show comparable biocompatibility with the clinically used PEG-b-PDLLA micelle. The improved therapeutic efficacy and safety demonstrate great promise for our strategy in future translational studies. [ABSTRACT FROM AUTHOR]

Assumption-free and in situ resolving of the kinetics of ligand binding to colloidal nanoparticles (NPs) with high time resolution is still a challenge in NP research. A unique concept of using spectra library and stopped-flow together with a "search best-match" Matlab algorithm to access the kinetics of ligand binding in colloidal systems is reported. Instead of deconvoluting superimposed spectra using assumptions, species absorbance contributions (ligand@ZnO NPs and ligand in solution) are obtained by offline experiments. Therefrom, a library of well-defined targets with known ligand distribution between particle surface and solution is created. Finally, the evolution of bound ligand is derived by comparing in situ spectra recorded by stopped-flow and the library spectra with the algorithm. Our concept is a widely applicable strategy for kinetic studies of ligand adsorption to colloidal NPs and a big step towards deep understanding of surface functionalization kinetics. [ABSTRACT FROM AUTHOR]

A novel light-induced reversible self-assembly (LIRSA) system is based on the reversible photodimerization and photocleavage of coumarin groups on the surface of gold nanoparticles (AuNPs) in THF solution. Facilitated by coumarin groups, light irradiation at 365 nm triggers the stable assembly of monodisperse AuNPs; the resulting self-assembly system can be disassembled back to the disassembled state by a relatively short exposure to benign UV light. The reversible self-assembly cycle can be repeated 4 times. A specific concentration range of coumarin ligand and the THF solvent were identified to be the two predominant factors that contribute to the LIRSA of AuNPs. This is the first successful application of reversible photodimerization based on a coumarin derivative in the field of AuNP LIRSA. This LIRSA system may provide unique opportunities for the photoregulated synthesis of many adjustable nanostructures and devices. [ABSTRACT FROM AUTHOR]

Durch äußere Stimuli ausgelöste Strukturumwandlungen spielen bei vielen biologischen Vorgängen eine wichtige Rolle, oft als Teil kinetisch gesteuerter Szenarien. Licht hat sich bei supramolekularen Nachbildungen solcher Systeme als perfekter externer Trigger erwiesen. Hier berichten wir über die lichtgesteuerte Strukturumwandlung eines kleinen, selbstassemblierten Pd3L6 ‐ Ringes, aufgebaut aus photochromen Dithienylethen(DTE) ‐ Liganden, zu einer rhombenkuboktaedrischen Pd24L48 ‐ Sphäre mit einem Durchmesser von 6.4 nm. Je nach Wahl der Wellenlänge kann dieser Prozess vollständig umgekehrt werden, wie durch NMR ‐ , UV/Vis ‐ und MS ‐ Messungen gezeigt werden konnte. Zudem konnte die Bildung der Sphäre mittels AFM, TEM und GISAXS nachgewiesen werden. Aufgrund unterschiedlicher Konformationen der Photoschalter in den isomeren Konstrukten zeigen die Geschwindigkeitskonstanten der Umwandlung zwischen beiden Strukturen eine starke Abhängigkeit von der Schaltrichtung. Licht an! In Position! Bestrahlung mit unterschiedlichen Wellenlängen steuert die reversible Umwandlung zwischen einem kleinem, selbstassemblierten Pd3L6 ‐ Ring basierend auf photochromen Dithienylethen ‐ Liganden und einer rhombenkuboktaedrischen Pd24L48 ‐ Sphäre mit 7 nm Durchmesser. [ABSTRACT FROM AUTHOR]

A hydrogel based on 1,3:2,4-dibenzylidenesorbitol (DBS), modified with acyl hydrazides which extracts gold/silver salts from model waste is reported, with preferential uptake of precious heavy metals over other common metals. Reduction of gold/silver salts occurs spontaneously in the gel to yield metal nanoparticles located on the gel nanofibers. High nanoparticle loadings can be achieved, endowing the gel with electrochemical activity. These hybrid gels exhibit higher conductances than gels doped with carbon nanotubes, and can be used to modify electrode surfaces, enhancing electrocatalysis. We reason this simple, industrially and environmentally relevant approach to conducting materials is of considerable significance. [ABSTRACT FROM AUTHOR]

Simultaneous delivery of multiple genes and proteins (e.g., transcription factors; TFs) is an emerging issue surrounding therapeutic research due to their ability to regulate cellular circuitry. Current gene and protein delivery strategies, however, are based on slow batch synthesis, which is ineffective, poorly controlled, and incapable of simultaneous delivery of both genes and proteins with synergistic functions. Consequently, advances in this field have been limited to in vitro studies. Here, by integrating microfluidic technologies with a supramolecular synthetic strategy, we present a high-throughput approach for formulating and screening multifunctional supramolecular nanoparticles (MFSNPs) self-assembled from a collection of functional modules to achieve simultaneous delivery of one gene and TF with unprecedented efficiency both in vitro and in vivo. We envision that this new approach could open a new avenue for immunotherapy, stem cell reprogramming, and other therapeutic applications. [ABSTRACT FROM AUTHOR]

The realization of controllable multicomponent self-assembly through reversible supramolecular interactions is a challenging goal, and is an important strategy for the fabrication of switchable nanomaterials. Herein we show that the self-assembly of TiO2 nanoparticles (NP) functionalized with methyl viologen can be controlled both by light irradiation and chemical reduction through cucurbit[8]uril-enhanced radical cation dimerization interactions. Moreover, the controlled assembly and disassembly of this system are accompanied by switchable photocatalytic activity of the TiO2 NPs, which shows potential application as a novel smart and recyclable photocatalyst. [ABSTRACT FROM AUTHOR]

Noninvasive imaging of kidney clearance kinetics (KCK) of renal clearable probes is key to studying unilateral kidney function diseases, but such imaging is highly challenging to achieve with in vivo fluorescence. While this long-standing challenge is often attributed to the limited light penetration depth, we found that rapid and persistent accumulation of conventional dyes in the skin "shadowed" real fluorescence signals from the kidneys and prevented non-invasive imaging of KCK, which, however, can be addressed with renal clearable nanofluorophores. By integrating near infrared emission with efficient renal clearance and ultralow background interference, the nanofluorophores can increase kidney-contrast enhancement and imaging-time window by approximately 50- and 1000-fold over conventional dyes, and significantly minimize deviation between noninvasive and invasive KCK, laying down a foundation for translating in vivo fluorescence imaging in preclinical noninvasive kidney function assessments. [ABSTRACT FROM AUTHOR]

Nanoparticle gold and gold-platinum catalysts supported on magnetite particles were used in the aerobic glycerol oxidation. Transmission electron microscopy analysis confirmed an icosahedral morphology of the gold catalyst and a flower-like structure for the gold-platinum catalyst. Dynamic light scattering analysis confirmed a mean diameter of 30 nm for both catalysts. This particle size was relatively stable for more than one month. The catalysts were easily recoverable from the reaction medium by means of magnetic force. No metal leaching was observed and the successfully reused catalysts showed only slight alteration. [ABSTRACT FROM AUTHOR]