Decoration Of Nanoparticles Research Articles

Effect of Pluronic P103 Concentration on the Simple Synthesis of Ag and Au Nanoparticles and Their Application in Anatase-TiO2 Decoration for Its Use in Photocatalysis.

Silver and gold nanoparticles were synthesized under environmentally-friendly reaction conditions by using a biodegradable copolymer and water as a solvent. The triblock copolymer Pluronic P103 was utilized as a stabilizing agent or soft template to produce Ag and Au nanoparticles (NPs) of different sizes. Moreover, in the synthesis of Au NPs, the polymer acted as a reducing agent, decreasing the number of reagents used and consequently the residues produced, hence, rendering the procedure less complicated. It was observed that as the concentration of the polymer increased, the size of the metallic NPs augmented as well. However, AgNPs and AuNPs prepared with 1 and 10 wt% Pluronic P103, respectively, showed a significant decrease in particle size due to the presence of polymeric soft templates. The hybrid materials (metal/polymer) were characterized by UV-Vis spectroscopy, DLS, and TEM. The pre-synthesized nanoparticles were employed to decorate anatase-TiO2, and the composites were characterized by DRS, XRD, BET surface area measurements, the TEM technique with the EDS spectrum, and XPS spectroscopy to demonstrate NPs superficial incorporation. Finally, methylene blue was used as a probe molecule to evidence the effect of NPs decoration in its photocatalytic degradation. The results showed that the presence of the NPs positively affected methylene blue degradation, achieving 96% and 97% removal by utilizing TAg0.1 and TAu10, respectively, in comparison to bare anatase-TiO2 (77%).

SI-ATRP Decoration of Magnetic Nanoparticles with PHEMA and Post-Polymerization Modification with Folic Acid for Tumor Cells' Specific Targeting.

Targeted nanocarriers could reach new levels of drug delivery, bringing new tools for personalized medicine. It is known that cancer cells overexpress folate receptors on the cell surface compared to healthy cells, which could be used to create new nanocarriers with specific targeting moiety. In addition, magnetic nanoparticles can be guided under the influence of an external magnetic field in different areas of the body, allowing their precise localization. The main purpose of this paper was to decorate the surface of magnetic nanoparticles with poly(2-hydroxyethyl methacrylate) (PHEMA) by surface-initiated atomic transfer radical polymerization (SI-ATRP) followed by covalent bonding of folic acid to side groups of the polymer to create a high specificity magnetic nanocarrier with increased internalization capacity in tumor cells. The biocompatibility of the nanocarriers was demonstrated by testing them on the NHDF cell line and folate-dependent internalization capacity was tested on three tumor cell lines: MCF-7, HeLa and HepG2. It has also been shown that a higher concentration of folic acid covalently bound to the polymer leads to a higher internalization in tumor cells compared to healthy cells. Last but not least, magnetic resonance imaging was used to highlight the magnetic properties of the functionalized nanoparticles obtained.

Facile synthesis of visible region luminescent silver decorated graphene oxide nanohybrid for biomedical applications: In combination with DFT calculations

Nanohybrid materials derived from silver nanoparticles (Ag-NPs) and graphene oxide (GO) attract substantial research consideration on account of their promising role in the biomedical field. The present study demonstrates an effectual method for decoration of silver nanoparticles over GO surface via an in-situ method, performed in an inert atmosphere. The incorporation of AgNPs on the GO surface was validated by various characterization techniques like XRD, SEM, EDAX, FTIR, and Raman analysis. The distribution of AgNPs on graphene sheets with lamellar morphology was observed. The Raman spectrum for Ag-GO nanohybrid was remarkably augmented, which owes to the existence of silver nanoparticles. The PL emission peaks of Ag-GO nanoparticles recorded around 418 and 440 nm ascribed to the interface of the localized surface plasmon resonance (LSPR) of silver nanoparticles and the inherent luminescence of GO. The density functional theory calculations (DFT) were executed for further understanding the HOMO-LUMO energy, adsorption energy and molecular structure of GO with Ag+. Additionally, the Ag-GO nanohybrid exhibited distinguishable antibacterial efficacy against E. coli (gram −ve) and S. aureus (gram +ve), in contrast to the results obtained for pristine GO, due to the synergistic impact of perforation of the bacterial wall by GO and silver ion release. The remarkable luminescent behaviour and antibacterial property of the as-synthesized Ag-GO nanohybrid reveal that it can be potentially used as a multifunctional weapon in the biomedical field.

WO3/C nanoarchitectures assembled with 1D nanowires: The synthesis, Pt nanoparticles decoration, and highly enhanced hydrogen evolution in neutral media

Electrochemical water splitting is an efficient approach to produce green hydrogen, while it is still very challenging to design of highly efficient WO3-based hydrogen evolution reaction (HER) catalysts especially those in neutral media. Here, 3D WO3/C nanoarchitectures assembled by 1D nanowires were prepared through water-oil two-phase microemulsion method and subsequent annealing treatment. The monodispersed Pt nanoparticles were loaded onto the WO3/C nanoarchitectures. A series of WO3/C composites were produced via modulating the addition of Pt salt. The optimum 2 Pt@WO3/C catalyst exhibited an overpotential of 149 mV at 10 mA cm−2 in neutral media, which was the first reported about the WO3-based materials and much better than most catalysts reported in literatures by far. Interestingly, the HER activity of 2 Pt@WO3/C was much higher than commercial Pt/C at high overpotential range (>260 mV). Density functional theory results demonstrated that the more toilless HER process could be attributed to the enhanced carrier densities, the electron transfer between Pt and W atoms, and the lowered energy barrier for water dissociation and H* desorption.

Manipulation of the SnSe2 gas sensing properties via Au nanoparticles decoration

Gas sensing devices play a key role in safety production, environment protection and human health. Recently, two-dimensional layered materials with large surface area and flexible optoelectronic properties have been widely used for gas sensor design. One of major concern in this field is the sensitivity and selectivity. Here, we show that the sensitivity and selectivity of SnSe2 gas sensor can be manipulated by Au nanoparticles decoration. By choosing NO2 (electron acceptor) and NH3 (electron donor) as target gas, we reveal that the “space charge layer” at the Au-SnSe2 Schottky junction interface plays a critical role in manipulating the sensitivity and selectivity. For NO2, the “space charge layer” hampers the electron transfer from SnSe2 to molecules, thus depressing the sensitivity. While, the electron transfer direction is the opposite when considering NH3, the “space charge layer” would facilitate the electron transfer, thus greatly improving the sensitivity of NH3. Especially, we show that the Au-decorated SnSe2 manifests a sensitivity about -22% toward 80 ppm NH3, which is about three times larger than that measured on pristine SnSe2 under UV illumination. These findings can not only deep our understanding on the mechanism of SnSe2 gas sensing, but also provide an effective strategy to manipulate the sensitivity and selectivity of SnSe2 detector for high performance and low cost gas sensor design.

Hybrid graphene-based materials and its catalytic activity toward hydrogen sorption

Thanks to unique material's properties, a remarkable research attention has been focused on graphene. In this research work, the Radio frequency (RF) sputtering technique process parameters were varied to achieve the well dispersed nanoparticles onto graphene sheets in the range of 5–10 nm to enhance the hydrogen sorption. On such scale, quantum size effects enter can play lowering the H2 desorption temperature from 400 °C typical of bulk Mg hydrides to 140 °C. In this context, the Magnesium (Mg) nanoparticles were decorated onto graphene sheets by varying the powder vibration frequency during the deposition process. X-ray diffraction (XRD) results demonstrate that the d spacing of graphene sheets was increased with decoration of Mg nanoparticles. Additionally the three characteristic peaks correspond to (001), (002) and (101) planes of hexagonal structure of metallic Mg were also observed. Transmission electron Microscope (TEM) micrographs revealed that the decorated Mg nanoparticles onto graphene at high powder vibration frequency were uniformly distributed over the entire sheet of graphene. Raman spectra showed that with the interaction of graphene with Mg nanoparticles the G and 2D peak were shifted 9.81 cm−1 and 8.2 cm−1 to higher wavenumbers, suggesting p doping of graphene. X-ray Photoemission Spectroscopy (XPS) results revealed that high concentration of Mg nanoparticles was obtained with high powder vibration frequency. The hydrogen up taking capacity for the decorated graphene sheets with Mg nanoparticles was about 6.00 wt% in whole composite. However, the up taking hydrogen storage capacity of the only Mg nanoparticles was 7.4 wt%.

The rapid detection for methane of ZnO porous nanoflakes with the decoration of Ag nanoparticles

The rapid detection for methane of ZnO porous nanoflakes with the decoration of Ag nanoparticles

The mode of dexamethasone decoration influences avidin-nucleic-acid-nano-assembly organ biodistribution and in vivo drug persistence

Avidin-Nucleic-Acid-NanoASsemblies (ANANAS) possess natural tropism for the liver and, when loaded with dexamethasone, reduce clinical progression in an autoimmune hepatitis murine model. Here, we investigated the linker chemistry (hydrazide-hydrazone, Hz-Hz, or carbamate hydrazide-hydrazone, Cb-Hz bond) and length (long, 5 kDa PEG, or short, 5-6 carbons) in biotin-dexamethasone conjugates used for nanoparticle decoration through in vitro and in vivo studies. All four newly synthesized conjugates released the drug at acidic pH only. In vitro, the Hz-Hz and the PEG derivatives were less stable than the Cb-Hz and the short chain ones, respectively. Once injected in healthy mice, dexamethasone location in the PEGylated ANANAS outer layer favors liver penetration and resident macrophages uptake, while drug Hz-Hz, but not Cb-Hz, short spacing prolongs drug availability. In conclusion, the tight modulation of ANANAS decoration can significantly influence the host interaction, paving the way for the development of steroid nanoformulations suitable for different pharmacokinetic profiles.

Prominent antibacterial effect of sub 5 nm Cu nanoparticles/MoS2 composite under visible light

Achieving an efficient and inexpensive bactericidal effect is a key point for the design of antibacterial agent. Recent advances have proved molybdenum disulfide (MoS2) as a promising platform for antimicrobial applications, while the combination of metal nanoparticle would promote the antibacterial efficiency. Nevertheless, the dispersivity, cheapness and safety of metal nanoparticle loaded on MoS2 raised some concerns. In this paper, we successfully realized a uniform decoration of copper nanoparticles (CuNPs) on surface of MoS2 nanosheets, and the size of CuNPs could be controlled below 5 nm. Under 5 min irradiation of 660 nm visible light, the synthesized CuNPs/MoS2 composite demonstrated superior antibacterial performances (almost 100% bacterial killed) towards both Gram-negative E. coli and Gram-positive S. aureus over the single component (Cu or MoS2), while the bactericidal effect could last for at least 6 h. The synergism of photodynamic generated hydroxyl radical (·OH), oxidative stress without reactive oxygen species production and the release of Cu ions was considered as the mechanism for the antibacterial properties of CuNPs/MoS2. Our findings provided new insights into the development of two-dimensional antibacterial nanomaterials of high cost performance.

Decoration of Ag Nanoparticle on ZnO Nanowire by Intense Pulsed Light and Enhanced UV Photodetector

Zinc oxide (ZnO) nanowires (NWs) are wide-bandgap semiconductors that absorb ultraviolet (UV) radiation. Various post-treatment processes have been studied to improve the optical properties of the as-grown ZnO NWs. Among them, Ag nanoparticles (NPs) effectively improved the optical properties on the surface of the ZnO NWs. In this study, ZnO NWs were synthesized via the hydrothermal synthesis method. ZnO NWs were decorated with Ag NPs on the surface of the ZnO NWs in a silver nitrate (AgNO3) aqueous solution by intense pulsed light (IPL) irradiation. Ag NPs were successfully decorated under the following conditions: aqueous AgNO3 solution of 100 nM, an energy of 1 J/cm2, and an exposure time of 8 ms. The responsivity and sensitivity of the ZnO NW UV photodetectors increased by 7.43 and 3.37 times, respectively. The IPL process makes it possible to decorate Ag NPs in a simple manner within an extremely short time.

Preparation and Application of a Hydrochar-Based Palladium Nanocatalyst for the Reduction of Nitroarenes.

In the present study, a novel heterogeneous catalyst was successfully fabricated through the decoration of palladium nanoparticles on the surface of designed Fe3O4-coffee waste composite (Pd-Fe3O4-CWH) for the catalytic reduction of nitroarenes. Various characterization techniques such as XRD, FE-SEM and EDS were used to establish its nano-sized chemical structure. It was determined that Pd-Fe3O4-CWH is a useful nanocatalyst, which can efficiently reduce various nitroarenes, including 4-nitrobenzoic acid (4-NBA), 4-nitroaniline (4-NA), 4-nitro-o-phenylenediamine (4-NPD), 2-nitroaniline (2-NA) and 3-nitroanisole (3-NAS), using NaBH4 in aqueous media and ambient conditions. Catalytic reactions were monitored with the help of high-performance liquid chromatography. Additionally, Pd-Fe3O4-CWH was proved to be a reusable catalyst by maintaining its catalytic activity through six successive runs. Moreover, the nanocatalyst displayed a superior catalytic performance compared to other catalysts by providing a shorter reaction time to complete the reduction in nitroarenes.

Synthesis of Cell-Penetrating Peptide Coated Silica Nanoparticles and Their Physicochemical and Biological Characterization.

The surface decoration of nanoparticles with cell-penetrating peptides (CPPs) represents a common technique for intracellular delivery of nanotherapeutics. Conjugate formation can be performed via covalent or non-covalent strategies. Here, we describe on the synthesis of silica nanoparticles, a well-known inorganic drug delivery vehicle type, and their surface modification with cell-penetrating peptides using sC18 and derivatives thereof. Moreover, physicochemical as well as biological characterization methods, including cellular uptake measurements, of particle-peptide conjugates are described.

Deposition of Ag nanoparticles on polydopamine-functionalized CNTs for improving the tribological properties of PPESK composites

In this study, CNTs were first modified by polydopamine (PDA) to facilitate their surface activation and then Ag nanoparticles were in-situ grown on CNT-PDA to obtain CNT-PDA/Ag. The effects of functionalized CNTs on the tribological behaviors of poly (phthalazinone ether sulfone ketone) (PPESK) were investigated. Results revealed that PDA layer could not only increase the active functional groups on the CNT surface, but also act as an activated platform for the deposition of mono-dispersed Ag nanoparticles. The decoration of Ag nanoparticles decreased the interaction among CNTs, which was conducive to their good dispersion. Besides, by filling 0.3 wt% CNT-PDA/Ag, the thermal properties of PPESK were significantly improved, and its friction-reduction and anti-wear performances were the best among all PPESK composites, due to the good interfacial interaction between CNTs and PPESK, the synergistic reinforcing and lubricating effect of CNTs and Ag nanoparticles, as well as the lubricating effect of transfer film.

High thermal conductivity of boron nitride filled epoxy composites prepared by tin solder nanoparticle decoration

To achieve a high thermal conductivity, thermally conductive polymer composites have been recently exploited, focusing on connecting a 3D network of thermally conductive fillers by applying external pressure or constructing a pre-made 3D filler framework to reduce phonon scattering within the polymer matrix. However, these approaches severely restrict the use of polymers, particularly epoxy composites, in many commercial applications such as the thermal management of electronic device packaging. In this study, a high-thermal-conductivity epoxy composite is fabricated by incorporating hexagonal boron nitride ( h -BN) decorated with tin nanoparticles (Sn NPs). Under a hybrid filler (Sn NPs on h -BN) loading (68 wt %), the composite exhibits a high thermal conductivity of 11.9 ± 0.29 W m −1 K −1 while maintaining a relatively low dielectric constant (D k ∼ 7.52) and loss (D f ∼ 0.023) at 1 MHz with a coefficient of thermal expansion of 34 ppm °C −1 . The Sn NPs on h -BN in the epoxy resin matrix are thermally percolated by the in-situ growth of Sn NPs under carefully controlled curing temperature and time, resulting in significantly improved thermal conductivity of the epoxy composite under pressure-less curing conditions.

Simultaneous improvements in antibacterial and flame retardant properties of PET by use of bio-nanotechnology for fabrication of high performance PET bionanocomposites

Recently, attentions to the applications of biotechnology and nanotechnology in the polymer industries have been greater than before. Hybrid nanocomposites containing multi-type of nano structures are widely established, but application of biotechnology for in-situ embedment of nanoparticles in polymer matrix is rarely reported. In this study, poly (ethylene terephthalate) (PET) based ternary bionanocomposites containing modified chitosan (phosphorylated chitosan) and nanosilver particles were prepared by simple eco-friendly method. Chitosan was selected as a biopolymer with respect to the biological activity and compatibility with PET. Phosphorylation of chitosan was achieved in order to introduce the phosphorus moieties as a flame retardant agent in PET matrix by using chemical approach. Also a cost-effective and environmentally friendly method was used for the in-situ fabrication and decoration of silver nanoparticles on to phosphorylated chitosan in PET matrix. Effects of the hybrid system (phosphorylated chitosan and silver nanoparticles) on the morphology, thermal behavior and antibacterial properties of the PET samples were investigated by different methods. The microstructure and homogeneity of the samples were analyzed by studying of dispersion of nanoparticles in PET via scanning electron microscopy. The antibacterial properties of PET nanocomposites can be improved by insertion of silver nanoparticles into the bulk of polymer matrix. Obtained results indicated that the PET/phosphorylated chitosan/silver nanocomposites showed a significantly higher growth inhibition rate compared with the PET and PET/phosphorylated chitosan blend. Also the flame retardant properties of PET nanocomposites were drastically enhanced.

Enhancing the Hydrogen-Sensing Performance of p-Type PdO by Modulating the Conduction Model.

The implementation of the p-type metal oxide semiconductor (MOS) in modern sensing systems requires a strategy to effectively enhance its inherent low response. However, for p-type MOS sensors, conventional methods such as catalyst nanoparticle (NP) decoration and grain size regulation do not work as effectively as they do for n-type MOS sensors, which is basically due to the fact that the p-type MOS adopts an unfavorable parallel conduction model. Herein, taking Au@PdO as an example, we demonstrate that the conduction model of the p-type MOS can be manipulated into the series conduction model by inserting a high-conductive metallic core into less-conductive p-type MOS NPs. This unique series conduction model makes the sensor response of Au@PdO nanoparticle arrays (NAs) very sensitive to the catalyst NP decoration as well as the change of structural parameters. For example, Au@PdO NAs demonstrate an ∼9000 times increase in sensor response when decorated with Pd NPs, whereas there is only ∼100 times increase for PdO NAs. This greatly improved response value outperforms all previously reported PdO-based (and most other p-type semiconductor-based) H2 sensors, which helps the obtained sensor to achieve an ultralow detection limit of ∼0.1 ppm at room temperature. Additionally, Au@PdO NAs inherit the high surface reactivity and gas adsorption property of p-type PdO. As a result, the as-prepared sensor exhibits high humidity-resistive property and excellent selectivity. This work provides a new strategy to significantly enhance the sensing performance of p-type gas sensors by manipulating their conduction model.

Decoration of Squalenoyl-Gemcitabine Nanoparticles with Squalenyl-Hydroxybisphosphonate for the Treatment of Bone Tumors.

Therapeutic perspectives of bone tumors such as osteosarcoma remain restricted due to the inefficacy of current treatments. We propose here the construction of a novel anticancer squalene‐based nanomedicine with bone affinity and retention capacity. A squalenyl‐hydroxybisphosphonate molecule was synthetized by chemical conjugation of a 1‐hydroxyl‐1,1‐bisphosphonate moiety to the squalene chain. This amphiphilic compound was inserted onto squalenoyl‐gemcitabine nanoparticles using the nanoprecipitation method. The co‐assembly led to nanoconstructs of 75 nm, with different morphology and colloidal properties. The presence of squalenyl‐hydroxybisphosphonate enhanced the nanoparticles binding affinity for hydroxyapatite, a mineral present in the bone. Moreover, the in vitro anticancer activity was preserved when tested in commercial and patient‐treated derived pediatric osteosarcoma cells. Further in vivo studies will shed light on the potential of these nanomedicines for the treatment of bone sarcomas.

Morphology and tensile performance of MWCNT/TiO2-epoxy nanocomposite

In this study, TiO2 nanoparticles are decorated on multi-walled carbon nanotubes (MWCNTs) by exploitation of opposite zeta potential of MWCNTs and TiO2 nanoparticles without degrading the hexagonal interatomic structure of MWCNT and generated new MWCNT/TiO2 hybrid nanofiller (MT hybrid nanofiller). The newly obtained MT hybrid nanofiller (from 0.25 wt% to 1.50 wt%) is loaded in crosslinking epoxy matrix to understand the multiphase nanocomposite in terms of mechanical performance under various stresses (storage modulus, loss modulus, tensile strength and modulus). The decoration of TiO2 nanoparticles on MWCNTs changes the fracture mechanism in the mirror zone and generates a new fracture surface, which changes the behavior of multiphase nanocomposite under various types of stresses.

TiO2 nanotube layers decorated by titania nanoparticles as anodes for Li-ion microbatteries

In this work, the utilization of TiO2 nanotube (TNT) layers decorated with TiO2 nanoparticles (NPs) as anodes in Li-ion microbatteries is reported for the first time. Such TiO2 NPs decorated TNT layers possess an increased amount of active material and a higher surface area compared with their non-decorated (blank) counterparts. TNT layers decorated with several different amounts of TiO2 NPs were tested by galvanostatic cycling tests. The capacities of the TiO2 NPs decorated TNT layer anodes increase with the amount of NPs decoration due to the enhancement of the capacitive effect. Indeed, an areal capacity of ∼126 μAh cm−2 (vs 88 μAh cm−2 for the non-decorated TNT layer) at the 200th cycle has been obtained after optimizing the NPs loading. On the other hand, a too high NPs loading of the TNT layers leads to a reduced areal capacity due to clogging of the nanotube exteriors and a significant decrease in inner diameter of the nanotubes.

Construction of Schottky contact by modification with Pt particles to enhance the performance of ultra-long V2O5 nanobelt photodetectors

Schottky-contacted nanosensors have attracted extensive attention due to their high sensitivity and fast response time. In this article, we proved that the construction of Schottky contact by Pt nanoparticles (NPs) decoration can effectively improve the performance of V2O5 nanobelts photodetectors. After modified by Pt NPs, the photocurrent of V2O5 nanobelts is increased by more than two orders of magnitude, and the photoresponse speed is improved by at least three orders of magnitude. Detailed studies have shown that the performance enhancement is attributed to the formation of the Schottky contact at the electrode-semiconductor interface due to the decrease of surface gas adsorption and the increase of V2O5 work function after Pt NPs modification. The strong built-in field in the Schottky barrier region will quickly separate photogenerated carriers, thereby reducing the electron-hole recombination rate, resulting in the fast response time and an increase in the free carrier density. Moreover, it is found that this enhancement effect can be regulated by controlling the pressure to modulating the Schottky barrier height at the interface. Overall, the Pt NPs-modified V2O5 nanobelts photodetector exhibits a broad response spectrum (visible to near infrared), fast rise/fall response time (less than 6.12/6.15 ms), high responsivity (5.6 A/W), and high specific detectivity (6.9 × 108 Jones). This study demonstrates the feasibility of building a Schottky barrier to enhance the photodetection performance, which provides a general and effective strategy towards the construction and its practical application of supersensitive and fast-response nanosensors.