Antioxidant activity of phytosynthesized biomatrix-loaded noble metallic nanoparticles

Biofabrication of noble monometallic platinum nanoparticles(Pt-NPs) and bimetallic gold–silver nanoparticles(Au Ag-NPs) using aqueous extract of Delonix regia is presented here. Antioxidant activity of biomatrix-loaded metallic nanoparticles is estimated for scavenging of two model radicals i.e., 2,2′-Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and 1,1′-Diphenyl-2-picrylhydrazyl. Broad spectral continuum spanning from visible to ultra-violet region(Pt-NPs: 30 min) and broad high intensity absorption peak around at 500 nm(Au Ag-NPs: 10 min) in two different UV–Visible spectra confirmed the biofabrication. Nanoparticles fabricated with distorted spherical shape and crystalline face-centred-cubic geometry. Strong signal around at 2.10 ke V(pure-phase platinum) and typical X-ray peaks observed at 2.20 and 3 ke V suggested, co-existence and alloying interaction of Au and Ag in Au Ag-NPs. ζ potential(-15.2 mV: Pt-NPs and -13.9 mV: Au Ag-NPs) values suggested surface adsorption of polyphenolic compounds to provide stability. Nanoparticles exhibited pronounced antioxidant activity against free radicals through their electron/hydrogen transfer ability.

One-step synthesis of FeO(OH)nanoparticles by electric explosion of iron wire underwater

In this study,we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging voltage.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS),showing the presence of iron and multiple iron-based compounds oxides with contents influenced by the experimental conditions.In particular,pure FeO(OH)nanoparticles were obtained using electric explosion of iron wire with energy input of 1125 J at charging voltage of 15 kV.Analysis of discharge current and resistive voltage data indicate that the high energy input induced bystrong plasma discharge at high charging voltage is a key factor to form FeO(OH).This study presents a one-step method to synthesize FeO(OH)nanoparticles using electric explosion of iron wire.

Dendrimer Templates for the Formation of Silver Nanoparticles

In order to control the size and shape of Ag nanoparticles obtained by using poly（amidoamine） （PA- MAM） dendrimer as template, the complexation between Ag^＋ ions and dendrimer studied extensively by UV-Vis spectroscopy and FTIR. After the Ag＋/PAMAM demdrimer being reduced by direct chemical reduction, Ag （0） nanopartides was formed, whose structure and characterization were studied by UV-Vis spectroscopy, transmission electron microscopy （TEM） and electron diffraction （ED） respectively. The results reveal that Ag nanopartides is a kind of face center cubic crystal and its average size is 4.5 nm. The solubility and stability of the solution containing Ag nanopartides also indicate that dendrimer is a good kind of template, as well as a protective agent.

Monitoring the penetration and accumulation of gold nanoparticles in rat skin ex vivo using surface-enhanced Raman scattering spectroscopy

Contamination by accidental cutaneous contact with the commercial products and the air pol-hutants raised a considerable health and safety issue.This study aimed to trace the dynamics of the 20 nm gold nanopartide(GNP)penetration and accumulation in rat skin tissues using a surface-enhanced Raman scattering(SERS)techmique.After the topical application of GNPs on rat skin surface,the SERS spectra were recorded for every 15 pum to an overall depth of 75 pum from skin surface for 150 min.The processes of GNP penetration in rat skin were accompanied by aggregation of GNPs,which affected SERS spectra.The results revealed that 20 nm GNPs can penetrate through stratum corneum layer,viable epidermis layer,and then into dermis layer.This study demonstrated for the first time the potential of SERS spectroscopy to monitor the penetration and accumulation of GNPs in rat skin.

Multifunctional core/satellite polydopamine@Nd^3＋- sensitized upconversion nanocomposite： A single 808 nm near-infrared light-triggered theranostic platform for in vivo imaging-guided photothermal therapy

Significant attenuation and overheating, caused by the absorption of the excitation band （980 nm） in water, are the major obstacles in the in vivo application of lanthanide-doped upconversion nanoparticles （UCNPs）. Therefore, appropriately- structured Nd3^＋-doped UCNPs with 808 nm excitation could be a promising alternative. Herein, we developed core-shell-shell structured Nd3^＋-sensitized UCNPs as imaging agents, and decorated them onto the surface of polydopamine （PDA） to construct a novel multifunctional core/satellite nanotheranostic （PDA@UCNPs） for in vivo imaging guidance photothermal therapy using single 808 nm laser irradiation. The core-shell-shell structured design enabled outstanding upconversion luminescence properties and strong X-ray attenuation, thereby making the nanocomposites potential candidates for excellent upconversion luminescence/computed tomography dual modal imaging. In addition, the PDA core not only provides high photothermal conversion efficiency and outstanding antitumor effect, but also endows the platform with robust biocompatibility owing to its natural features. Therefore, this multifunctional nanocomposite could be a promising theranostic in future oncotherapy, with high therapeutic effectiveness but low side effects. This study would stimulate interest in designing bio- application-compatible multifunctional nanocomposites, especially for cancer diagnosis and treatment in vivo.

Self-standing Na-storage anode of Fe2O3 nanodots encapsulated in porous N-doped carbon nanofibers with ultra-high cyclic stability

Ultrasmall y-Fe203 nanodots （- 3.4 nm） were homogeneously encapsulated in interlinked porous N-doped carbon nanofibers （labeled as Fe2O3@C） at a considerable loading （-51 wt.%） via an electrospinning technique. Moreover, the size and content of Fe2O3 could be controlled by adjusting the synthesis conditions. The obtained Fe203@C that functioned as a self-standing membrane was used directly as a binder- and current collector-free anode for sodium-ion batteries, displaying fascinating electrochemical performance in terms of the exceptional rate capability （529 mA.h.gq at 100 mA-g-1 compared with 215 mA-h-g-1 at 10,000 mA.g-1） and unprecedented cyclic stability （98.3% capacity retention over 1,000 cycles）. Furthermore, the Na-ion full cell constructed with the Fe2O3C anode and a P2-Na2/3Ni1/3Mn2/302 cathode also exhibited notable durability with 97.2% capacity retention after 300 cycles. This outstanding performance is attributed to the distinctive three-dimensional network structure of the very-fine Fe203 nanoparticles uniformly embedded in the interconnected porous N-doped carbon nanofibers that effectively facilitated electronic/ionic transport and prevented active materials pulverization/aggregation caused by volume change upon prolonged cycling. The simple and scalable preparation route, as well as the excellent electrochemical performance, endows the Fe2O3@C nanofibers with great prospects as high-rate and long-life Na-storage anode materials.

Visually monitoring the etching process of gold nanoparticles by KI/12 at single-nanoparticle level using scattered-light dark-field microscopic imaging

Real-time monitoring of reaction processes is helpful for understanding the reaction mechanisms. In this study we investigated the etching mechanism of gold nanopartides （AuNPs） by iodine on a single-nanopartide level because AuNPs have become important nanoprobes with applications in sensing and bioimaging fields owing to their specific localized surface plasmon resonance （LSPR） properties. By using a scattered-light dark-field microscopic imaging （iDFM） technique, the in situ KI/I2-treated etching processes of various shapes of AuNPs, including nanospheres （AuNSs）, nanorods （AuNRs）, and nanotrigonal prisms （AuNTs）, were monitored in real time. It was found that the scattered light of the different shapes of AuNPs exhibited noticeable color changes upon exposure to the etching solution. The scattering spectra during the etching process showed obvious blue-shifts with decreasing scattered intensity owing to the oxidation of Au atoms into [AuI2]-. Both finite-difference time-domain （FDTD） simulations and monitoring of morphological variations proved that the etching was a thermodynamic-dependent process through a chamfering mechanism coupled with layer-by-layer peeling, resulting in isotropic spheres with decreased particle sizes.

A prospective cancer chemo-immunotherapy approach mediated by synergistic CD326 targeted porous silicon nanovectors

Combination therapy via nanoparticulate systems has already been proposed as a synergistic approach for cancer treatment. Herein, undecylenic acid modified thermally hydrocarbonized porous silicon nanoparticles （UnTHCPSi NPs） loaded with sorafenib and surface-biofunctionalized with anti-CD326 antibody （Ab） were developed for cancer chemo-immunotherapy in MCF-7 and MDA-MB-231 breast cancer cells. The cytocompatibility study showed no significant toxicity for the bare and antibody-conjugated UnTHCPSi （Un-Ab） NPs at concentrations lower than 200 μg·mL^-1. Compared to the bare UnTHCPSi, Un-Ab NPs loaded with sorafenib reduced the premature drug release in plasma, increasing the probability of proper drug targeting. In addition, high cellular interaction and subsequent internalization of the Un-Ab NPs into the cells expressing CD326 antigen demonstrated the possibility of improving antigen-mediated endocytosis via CD326 targeting. While an in vitro antitumor study revealed a higher inhibitory effect of the sorafenib-loaded Un-Ab NPs compared to the drug-loaded UnTHCPSi NPs in the CD326 positive MCF-7 cells, there was no difference in the anti-proliferation impact of both the abovementioned NPs in the CD326 negative MDA-MB-231 cells, suggesting CD326 as an appropriate receptor for Ab-mediated drug delivery. It was also shown that the anti-CD326 Ab can act as an immunotherapeutic agent by inducing antibody dependent cellular cytotoxicity and enhancing the interaction of effector immune and cancer cells for subsequent phagocytosis and cytokine secretion. Hence, the developed nanovectors can be applied for simultaneous tumor-selective drug targeting and immunotherapy.

Efficient Self-Assembled DNA Nanoparticles through Rolling Circle Amplification for siRNA Delivery in vitro

Effective and low toxicity delivery of siRNA is of great importance for clinical gene therapy. Herein, self-assembled DNA nanoparticles (NPs) based on rolling circle amplification (RCA) with a small interfering RNA (siRNA) payload were successfully developed as a facile and efficient siRNA delivery strategy. This intracellular gene silencing strategy exhibits various advantages including low toxicity, high efficiency, and good stability. The synthesized DNA NPs serve as siRNA carriers, protecting the siRNA against nuclease degradation. We demonstrate that the obtained self-assembled siRNA/NP/PEI system can successfully deliver enhanced green fluorescent protein (EGFP)-siRNA into HeLa cells, realizing the same EGFP knockdown efficiency with less toxicity as that of commercial Lipofectamine 2000.

Converting ultrafine silver nanoclusters to monodisperse silver sulfide nanoparticles via a reversible phase transfer protocol

To achieve better control of the formation of silver sulfide （Ag2S） nanoparticles, ultrasmall Ag nanoclusters protected by thiolate ligands （Ag44（SR）30 and Agla（GSH）9） are used as precursors, which, via delicate chemistry, can be readily converted to monodisperse Ag2S nanoparticles with controllable sizes （4-16 nm） and switchable solvent affinity （between aqueous and organic solvents）. This new synthetic protocol makes use of the atomic monodispersity and rich surface chemistry of Ag nanoclusters and a novel two-phase protocol design, which results in a well-controlled reaction environment for the formation of Ag2S nanopartides.

Construction of Chiroptical Switch on Silica Nanopartide Surface via Chiral Self-assembly of Side-chain Azobenzene-containing Polymer

In this contribution,we utilized surface initiated atom transfer radical polymerization(SI-ATRP)to prepare organicinorganic hybrid core/shell silila nanoparticles(NPs),where silia particles acted as cores and polymeric shells(PAzoMA*)were attached to silica particles via covalent bond.Subsequently,chiroptical switch was sccessfully constructed on silica NPs surface taking advantage of supramolecular chiral self-assembly of the grafted side chain Azo-containing polymer(PAzoMA*).We found that the supramolecular chirality was highly dependent on the molecular weight of grafted PAzoMA*.Meanwhile,the supramolecular chirality could be regulated using 365 nm UV light iradiation and heating cooling treatment,and a reversible supramolecular chiroptical switch could be repeated for over five cycles on silia NPs surface.Moreover,when heated above the glass transition temperature(T_(g))of PAzoMA",the organic-inorganic hybrid nanoparticles(SiO_(2)@PAzoMA*NPs)still exhibited intense DRCD signals.Interestingly,the supramolecular chirality could be retained in solid film for more than 3 months.To conclude,we have prepared an organic inorganic hybrid core/shell chiral slia nanomaterial with dynamic reversible chirality,thermal stability and chiral storage functions,providing potential applications in dynamic asymmetric catalysis,chiral separation and so on.

Harnessing the collective properties of nanoparticle ensembles for cancer theranostics

Individual inorganic nanoparticles （NPs） have been widely used in the fields of drug delivery, cancer imaging and therapy. There are still many hurdles that limit the performance of individual NPs for these applications. The utilization of highly ordered NP ensembles opens a door to resolve these problems, as a result of their new or advanced collective properties. The assembled NPs show several advantages over individual NP-based systems, such as improved cell internalization and tumor targeting, enhanced multimodality imaging capability, superior combination therapy arising from synergistic effects, possible complete clearance from the whole body by degradation of assemblies into original small NP building blocks, and so on. In this review, we discuss the potential of utilizing assembled NP ensembles for cancer imaging and treatment by taking plasmonic vesicular assemblies of Au NPs as an example. We first summarize the recent developments in the self-assembly of plasmonic vesicular structures of NPs from amphiphilic polymer-tethered NP building blocks. We further review the utilization of plasmonic vesicles of NPs for cancer imaging （e.g. multi-photon induced luminescence, photothermal, and photoacoustic imaging）, and cancer therapy （e.g., photothermal therapy, and chemotherapy）. Finally, we outline current challenges and our perspectives along this line.

Magnetic labeling of natural lipid encapsulations wit ron-based nanoparticles

With superior biocompatibility and unique magnetic properties, iron-based nanoparticles （IBNP） are commonly encapsulated in cells and extracellular vesicles （EV） to allow for magnetic force controlled drug delivery and non-invasive tracking. Based on their natural source and similar morphologs; we classify both cells and EVs as being natural lipid encapsulations （NLEs）, distinguishing them from synthetic liposomes. Both their imaging contrast and drug effects are dominated by the amount of iron encapsulated in each NLE, demonstrating the importance of magnetic labeling efficiency. It is known that the membranes function as barriers to ensure that substances pass in and out in an orderly manner. The most important issue in increasing the cellular uptake of IBNPs is the interaction between the NLE membrane and IBNPs, which has been found to be affected by properties of the IBNPs as well as NLE heterogeneity. Two aspects are important for effective magnetic labelling： First, how to effectively drive membrane wrapping of the nanoparticles into the NLEs, and second, how to balance biosafety and nanoparticle uptake. In this review, we will provide a systematic overview of the magnetic labeling of NLEs with IBNPs. This article provides a summary of the applications of magnetically labeled NLEs and the labeling methods used for IBNPs. The review also analyzes the role of IBNPs physicochemical properties, especially their magnetic properties, and the of NLEs in the internalization pathway. At the same time, the future of magnetically labeled NLEs is also discussed. development

Porous ternary complex metal oxide nanoparticles converted from core/shell nanoparticles

We demonstrate an easy and scalable low-temperature process to convert porous ternary complex metal oxide nanoparticles from solution-synthesized core^shell metal oxide nanopartides by thermal annealing. The final products demonstrate superior electrochemical properties with a large capacity and high stability during fast charging/discharging cycles for potential applications as advanced lithium-ion battery （LIB） electrode materials. In addition, a new breakdown mechanism was observed on these novel electrode materials.

Background-free three-dimensional selective imaging of anisotropic plasmonic nanoparticles

There is an increasing demand for advanced optical imaging techniques that can detect and resolve nanosize objects at a spatial resolution below the optical diffraction limit, especially in three-dimensional （3D） cellular environments. In this study, using a polarization-activated localization scheme based on the orientation-dependent properties of anisotropic plasmonic metal nanoparticles （MNPs）, ＂photoswitchable＂ imaging of single gold nanorods （AuNRs） was accomplished not only in two dimensions but also in three dimensions. Moreover, the Rayleigh scattering background arising from the congested subcellular structures was efficiently suppressed. Thus, we obtained the 3D distributions of both the position and the orientation of the AuNRs inside the cells and investigated their intemalization kinetics. To our knowledge, this is the first demonstration of the confocal-like 3D imaging of non-fluorescence nanoparticles with a high resolution and almost zero background. This technique is easy to implement and should greatly facilitate MNP studies and applications in biomedicine and biology.

A new oxidovanadium(Ⅳ) Schiff base complex containing asymmetric tetradentate ONN0O0Schiff base ligand:Synthesis,characterization,crystal structure determination,thermal study and catalytic activity

After synthesis of an asymmetric tetradentate ONN＇O＇ Schiff base ligand （H2L） followed by reaction of the synthesized H2L with an equimolar mixture of methanolic solutions of the VO（acac）2, a new oxidovanadium（IV） Schiff base complex （VOL） was synthesized. The Schiff base ligand and its complex were characterized by FT-IR and UV-vis spectra and C, H, N analysis, The crystal structure of VOL was also determined by single crystal X-ray analysis. The VOL complex crystallizes in monoclinic space group Cc. The Schiffbase ligand acts as a tetradentate ligand through its two＇iminic nitrogens and two phenolic and acetylacetonate oxygens. Thermogravimetric analysis of the VOL showed that it decomposes in two steps and converts to mixed vanadium oxides at 477℃. In addition, thermal decomposition of the VOL complex in air at 660 ℃ leads to formation of V2O5 nanoparticles with the average size estimated from XRD 49 nm. The catalytic activity of the VOL complex was investigated in the epoxidation reaction and different reaction parameters were optimized. The results showed that the cyclic alkenes were efficiently converted to the corresponding epoxides, whereas the VOL did not appreciably convert the linear alkenes.