Monodisperse Nanoparticles Research Articles

Second near-infrared fluorescent dye for lateral flow immunoassays rapid detection of influenza A/B virus

Sensitive and rapid diagnostic point of care testing (POCT) system is of great significance to prevent and control human virus infection. Here reported an immunochromatographic strip technology. The second near-infrared (NIR-II) fluorescent dye encapsulated into polystyrene (PS) nanoparticles, was integrated into a lateral flow assay platform to achieve excellent detection of influenza A/B. This surface-functionalized and mono-dispersed PS nanoparticles has been conjugated with influenza nucleoprotein monoclonal antibody as targets for influenza antigen-detection. This assay achieved the detection limit of 0.015 ng/mL for influenza A nucleoprotein and 4.3*10−5 HAU/mL (102.08 TCID50/mL) influenza A virus (influenza B: 0.037 ng/mL, 9.7*10−7 HAU/mL (100.43 TCID50/mL)). Compared with an Au-based lateral flow test strip, the strip's sensitivity is about 16-fold higher than it. Strip detection properties remain stable for 6 months under 4 °C to 30 °C storage. The assay's intra assay variation is 5.14% and the inter assay variation is 7.74%. Other potential endogenous and exogenous interfering substances (whole blood, nasal mucin, saliva, antipyretics, antihistamines and neuraminidase inhibitors) showed negative results, which verified the excellent specificity of this method. This assay was successfully applied to the POCT quantitative detection of influenza A/B virus, the sensitivity to influenza A and B viruses was 70% and 87.5% respectively, and the specificity was 100%. Therefore, these microspheres can be used as an effective material for rapid POCT detection in clinical specimens.

Remdesivir-loaded bis-MPA hyperbranched dendritic nanocarriers for pulmonary delivery

Remdesivir is the only clinically available antiviral drug for the treatment of COVID-19. However, its very limited aqueous solubility confines its therapeutic activity and the development of novel inhaled nano-based drug delivery systems of remdesivir for enhanced lung tissue targeting and efficacy is internationally pursued. In this work 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) hyperbranched dendritic nano-scaffolds were employed as nanocarriers of remdesivir. The produced nano-formulations, empty and loaded, consisted of monodisperse nanoparticles with spherical morphology and neutral surface charge and sizes ranging between 80 and 230 nm. The entrapment efficiency and loading capacity of the loaded samples were 82.0% and 14.1%, respectively, whereas the release of the encapsulated drug was complete after 48 h. The toxicity assays in healthy MRC-5 lung diploid fibroblasts and NR8383 alveolar macrophages indicated their suitability as potential remdesivir carriers in the respiratory system. The novel nano-formulations are non-toxic in both tested cell lines, with IC50 values higher than 400 μΜ after 72 h treatment. Moreover, both free and encapsulated remdesivir exhibited very similar IC50 values, at the range of 80–90 μM, while its aqueous solubility was increased, overall presenting a suitable profile for application in inhaled delivery of therapeutics.

Radioluminescent Photonic Bandgap Hydrogels: Mechanochromic Tunable Emissions.

Fully organic, radioluminescent crystalline colloidal arrays (CCAs) with covalently incorporated emitters were synthesized by using up to three organic fluorophores that were Förster resonance energy transfer (FRET) pairs with each other. The emitters were covalently incorporated into monodisperse poly(styrene-co-propargyl acrylate) nanoparticles in various combinations, resulting in blue-, green-, and red-emitting CCAs when excited with an X-ray source. The negatively charged surfaces of the monodisperse nanoparticles caused self-assembly into a crystal-like structure, which resulted in a partial photonic bandgap (i.e., rejection wavelength) within the near-visible and visible light spectrum. When the rejection wavelength of the CCA overlapped its radioluminescence, the spontaneous emission was inhibited and the emission intensity decreased. A poly(ethylene glycol) methacrylate-based hydrogel network was used to encapsulate the CCAs and stabilize their crystal-like structure. Within the hydrogel, coupling the photonic bandgap with the radioluminescence of the CCA films led to robust optical systems with tunable emissions. These fully organic, hydrogel-stabilized, radioluminescent CCAs possess mechanochromic tunable optical characteristics with future applications as potentially less toxic X-ray bioimaging materials.

Evaluation and Design of Colored Silicon Nanoparticle Systems Using a Bidirectional Deep Neural Network.

Silicon nanoparticles (SiNPs) with lowest-order Mie resonance produce non-iridescent and non-fading vivid structural colors in the visible range. However, the strong wavelength dependence of the radiation pattern and dielectric function makes it very difficult to design nanoparticle systems with the desired colors. Most existing studies focus on monodisperse nanoparticle systems, which are unsuitable for practical applications. This study combined the Lorentz–Mie theory, Monte Carlo, and deep neural networks to evaluate and design colored SiNP systems. The effects of the host medium and particle size distribution on the optical and color properties of the SiNP systems were investigated. A bidirectional deep neural network achieved accurate prediction and inverse design of structural colors. The results demonstrated that the particle size distribution flattened the Mie resonance peak and influenced the reflectance and brightness of the SiNP system. The SiNPs generated vivid colors in all three of the host media. Meanwhile, our proposed neural network model achieved a near-perfect prediction of colors with high accuracy of the designed geometric parameters. This work accurately and efficiently evaluates and designs the optical and color properties of SiNP systems, thus accelerating the design process and contributing to the practical production design of color inks, decoration, and printing.

Turbulent melting characteristics of hybrid nano-enhanced molten salt phase change material in rectangular enclosure

The turbulent melting characteristics of hybrid nano-enhanced phase change material (HNEPCM) in a three-dimensional rectangular enclosure has been numerically investigated. The lower and upper walls are partially heated and cooled using constant surface temperature boundary condition and the other surfaces are specified with adiabatic boundary condition. The rectangular enclosure is filled with molten salt phase change material (PCM) of potassium nitrate (KNO3) with melting temperature of 334 °C. The transient melting rates of PCM are investigated by dispersing hybrid mono-dispersed spherical nanoparticles of Aluminum oxide (Al2O3) combined with Silicon dioxide (SiO2), Titanium dioxide (TiO2) and Multi-walled carbon nanotubes (MWCNT). The Rayleigh number (Ra) and particle volume fraction (ϕ) are varied in the range of 106≤Ra≤1010 and 2%≤ϕ≤5%. The turbulent phase change process of PCM is modeled using enthalpy–porosity approach with Lam–Bremhorst k−ϵ turbulence model. The three-dimensional governing equations are discretized using Finite difference technique and computations are carried out using Fortran 90 in-house code. The stronger thermal buoyancy force accelerates the melting rate and the melting pattern indicates the accumulation of large quantity of molten metal in the upper regions of the rectangular enclosure. The average melting velocity and turbulent kinetic energy of pure KNO3 PCM is increased by 51.17% and 77.84% by the addition of Al2O3−MWCNT hybrid nanoparticles. The impact of hybrid nanoparticles on the melting rate and thermal performance of PCM is significant in higher Rayleigh number flows than transitional flows. The present results are validated and are in close agreement with the benchmark experimental results.

Screening strategies for surface modification of lipid-polymer hybrid nanoparticles

Lipid-polymer hybrid nanoparticles are promising platforms in the field of targeted drug delivery, integrating the positive features of polymeric and lipid nanocarriers. However, the use of bulk procedures in lipid-polymer hybrid nanoparticles formulation is hindering their large-scale manufacturing. Therefore, the aim of this study is to explore the suitability of alternative formulation methods, such as microfluidics, to obtain surface-tunable nanoparticles displaying suitable characteristics. Formulations were prepared by single-step nanoprecipitation or using a micromixer chip. The nanocarriers were then surface-modified with an aptamer and an antibody, two common nanoparticle vectorization strategies, developing an optimized functionalization protocol. Both naked and surface-modified nanoparticles were characterized in terms of size, polydispersity, zeta potential and morphology. Moreover, the aptamer/antibody association efficiency was also determined. Nano-sized monodisperse nanoparticles, exhibiting a spherical core–shell structure, were obtained through both procedures. Furthermore, all the nanocarriers were successfully functionalized, showing association efficiency values above 70%. Interestingly, microfluidic-based nanoparticles displayed a smaller size and a more positive zeta potential than those prepared by single-step nanoprecipitation. Outcomes suggest both techniques led to lipid-polymer hybrid nanoparticles displaying a similar functionalization efficiency. Conversely, the microfluidic approach provided an improved control over critical parameters, as particle size or charge, constituting an interesting alternative to traditional formulation procedures.

(Invited, Digital Presentation) Enhancement of Magnetic Dipole Transition of Molecules By Silicon Nanoparticle Nanoantenna

A nanoantenna is a nanodevice that manipulates light propagation and enhances light-matter interaction at the nanoscale. Integration of an emitter into a nanoantenna capable of increasing local density of photonic states at the emission wavelength results in the enhanced spontaneous emission rate (Purcell effect). The most widely studied nanoantennas for the Purcell enhancement are plasmonic nanoantennas made from gold or silver nanostructures supporting surface plasmon resonances. In most cases, nanoantennas have been used for the enhancement of electric dipole-allowed transition of a molecule. In addition, recently, nanoantennas capable of enhancing magnetic dipole transition of a molecule are attracting attention. For the magnetic Purcell enhancement, nanoantennas have to have magnetic resonances at the optical frequency. Although it is possible to achieve magnetic resonances at the optical frequency by plasmonic nanostructures, the inherent absorption loss of noble metals limits the magnetic Purcell enhancement. On the other hand, nanoparticles of high refractive index dielectrics inherently have low-loss magnetic-type Mie resonances at the optical frequency, and thus are potentially more attractive as a material to realize large magnetic Purcell enhancement.We have developed spherical nanoparticles of crystalline silicon (Si) having the magnetic dipole (MD) and quadrupole (MQ) Mie resonances at the optical frequency [1]. In this work, to demonstrate the potential of a Si nanoparticle as a nanoantenna for the magnetic Purcell enhancement, we develop a composite nanoparticle, that is, a Si nanosphere decorated with europium ion (Eu3+) complexes, in which magnetic dipole emission of Eu3+ is efficiently coupled to the magnetic Mie modes of the nanosphere [2]. We systematically investigate the light scattering and photoluminescence spectra of the coupled system by means of single particle spectroscopy. The results are shown in Figure 1. By tuning the MQ Mie resonance of a Si nanosphere to the 5D0-7F1 magnetic dipole transition of Eu3+, the branching ratio between the magnetic and electric dipole (5D0-7F2) transitions is enhanced up to 7 times. The observed large magnetic Purcell enhancement offers an opportunity to develop novel fluorophores with enhanced magnetic dipole emission. Furthermore, the enhanced magnetic field of dielectric Mie resonators enhances otherwise very weak absorption due to magnetic dipole transition, and makes direct excitation of triplet states of a molecule possible [3]. Direct excitation of triplet states reduces photon energy necessary for energy conversion and chemical reactions utilizing a triplet state compared to a conventional process involving singlet-singlet excitation and singlet-triplet intersystem crossing.[1] H. Sugimoto, et. al., "Mie Resonator Color Inks of Monodispersed and Perfectly Spherical Crystalline Silicon Nanoparticles" Advanced Optical Materials, 8 (2020) 2000033.[2] H. Sugimoto, and Minoru Fujii, "Magnetic Purcell Enhancement by Magnetic Quadrupole Resonance of Dielectric Nanosphere Antenna", ACS Photonics, 8 (2021) 1794.[3] H. Sugimoto, et. al., "Direct Excitation of Triplet State of Molecule by Enhanced Magnetic Field of Dielectric Metasurfaces", Small, 2021, DOI: 10.1002/smll.202104458.Figure 1: Photoluminescence (red curves) and scattering (black curves) spectra of single Si naosphere-Eu3+ complex composite nanoparticles with different Si nanosphere diameters. The diameters are shown at the right end of the figure. Figure 1

Indocyanine green potentiated paclitaxel nanoprodrugs for imaging and chemotherapy.

Self-assembled prodrug nanoparticles with tumor-responsive capacity have great potential in tumor visualization and treatment. However, the nanoparticle formulas usually contain multiple components, especially polymeric materials, which result in various potential issues. Herein, we report an indocyanine green (ICG)-driven assembly of paclitaxel prodrugs integrating near-infrared fluorescence imaging and tumor-specific chemotherapy. By feat of the hydrophilic merit of ICG, paclitaxel dimer could form more uniformly monodispersed nanoparticles. This two-in-one strategy reinforces the complementary advantages, resulting in superior assembly behavior, robust colloidal stability, enhanced tumor accumulation as well as desirable near-infrared imaging and in vivo feedback of chemotherapy. The in vivo experiments validated the prodrug activation at tumor sites as evidenced by enhanced fluorescence intensity, potent tumor growth suppression, and reduced systemic toxicity compared with commercial Taxol. The universality of ICG potentiated strategy toward photosensitizers and fluorescence dyes was confirmed. This presentation provides deep insight into the feasibility of constructing clinical-close alternatives for improving antitumor efficacy.

Zinc-Containing Sol-Gel Glass Nanoparticles to Deliver Therapeutic Ions.

Zn-containing dense monodispersed bioactive glass nanoparticles (Zn-BAGNPs) have been developed to deliver therapeutic inorganic trace elements, including Si, Ca, Sr, and Zn, to the cells through the degradation process, as delivery carriers for stimulating bone regeneration because of their capacity to induce osteogenic differentiation. The sol–gel-derived dense silica nanoparticles (SiO2-NPs) were first synthesized using the modified Stöber method, prior to incorporating therapeutic cations through the heat treatment process. The successfully synthesized monodispersed Zn-BAGNPs (diameter of 130 ± 20 nm) were homogeneous in size with spherical morphology. Ca, Sr and Zn were incorporated through the two-step post-functionalization process, with the nominal ZnO ratio between 0 and 2 (0, 0.5, 1.0, 1.5 and 2.0). Zn-BAGNPs have the capacity for continuous degradation and simultaneous ion release in SBF and PBS solutions due to their amorphous structure. Zn-BAGNPs have no in vitro cytotoxicity on the murine pre-osteoblast cell (MC3T3-E1) and periodontal ligament stem cells (PDLSCs), up to a concentration of 250 µg/mL. Zn-BAGNPs also stimulated osteogenic differentiation on PDLSCs treated with particles, after 2 and 3 weeks in culture. Zn-BAGNPs were not toxic to the cells and have the potential to stimulate osteogenic differentiation on PDLSCs. Therefore, Zn-BAGNPs are potential vehicles for therapeutic cation delivery for applications in bone and dental regenerations.

Anisotropic Particle Fabrication Using Thermal Scanning Probe Lithography

Size, shape, and chemical properties of nanoparticles are powerful tools to modulate the optical and physicochemical properties of a particle suspension. Despite having many methods to synthesize anisotropic nanoparticles, often there are challenges in terms of controlling the polydispersity, shape, size, or composition of anisotropic nanoparticles. This work has been inspired by the potential for developing a unique pathway to make different shaped monodispersed anisotropic nano- and microparticles with large flexibility in material choice. Compared to existing methods, this state-of-the-art nanolithographic method is fast, easy to prototype, and much simple in terms of its mechanical requirement. We show that this technique has been efficiently used to make a variety of anisotropic nano- and microparticles of different shapes, such as triangular prisms, ovals, disks, flowers, and stairs following the same pathway, at the same time showing the potential of being flexible with respect to the composition of the particles. The thermal scanning probe lithographic method in combination with dry reactive ion etching was used to make two-dimensional and three-dimensional templates for the fabrication of anisotropic nano- and microparticles. Deposition of different metal/metal oxides by the electron-beam evaporation method onto these templates allowed us to fabricate a range of nanomaterials according to the required functionality in potential applications. The particles were characterized by atomic force microscopy, He-ion microscopy, scanning electron microscopy, and dynamic light scattering to ensure that the developed method is reproducible, flexible, and robust in choosing the shapes for making monodispersed anisotropic nanoparticles with great control over shape and size.

Biosynthesis of cadmium sulfide nanoparticles using aqueous extract of Lactobacillus acidophilus along with its improvement by response surface methodology

Although the biosynthesis of nanoparticles by microorganisms can overcome problems associated with common synthesis methods, using pathogenic bacteria, isolating nanoparticles from the cell, and having producing agents in broth media are challenging. This research aimed to biosynthesize cadmium sulfide nanoparticles from the aqueous extract of Lactobacillus acidophilus and improve the biosynthesis process by response surface methodology. The biosynthesis process was conducted by the aqueous extract as a producing, stabilizing, and capping agent, accompanied by cadmium chloride and sodium sulfide solutions as cadmium sulfide precursors in a ratio of 1:10:10, respectively, considering pH and temperature as process variables. Ultraviolet–visible spectroscopy of colloidal aqueous solution showed a peak with an average maximum absorbance of 0.161 ± 0.023 after 18 h of incubation in un-optimized conditions which was improved up to 0.204 ± 0.049 under pH 9 and temperature of 50 °C in optimized conditions. Field emission scanning electron microscopy indicated monodispersed spherical nanoparticles with an average size of 19.07 ± 2.54 nm in optimized conditions. X-ray diffraction revealed the formation of cubic/hexagonal crystallites in an amorphous matrix. Fourier transform infra-red spectroscopy determined functional groups involved in the biosynthesis. The findings of this research showed that the bacterium aqueous extract has a good potential for the biosynthesis of nanoparticles.

Reduction and removal of methylene blue from aqueous solutions via recyclable magnetic gold nanomaterials

Nano-sized iron oxide particles displaying superparamagnetism (SPIONs), were synthesised using the co-precipitation method. Gold-coated SPIONs stabilised by phosphine ligands (1,3,5-triaza-7-phosphaadamantane (PTA) or triphenylphosphine (PPh3)), were immobilised on the surface of these SPIONs. A total of 19 nanomagnetic systems were synthesised, with varying Au loading, stabilisers and reducing agents employed. The obtained nanomaterials were fully characterised by ultraviolet visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FT-IR), powder X-Ray diffraction (PXRD), high-resolution transmission electron microscopy (HRTEM) and inductively coupled plasma spectroscopy (ICP). The PTA ligand was a better stabiliser than the PPh3 ligand, resulting in more monodisperse nanoparticles for the former. These nanomaterials were subsequently used for the treatment of wastewater from the textile industry, specifically methylene blue (MB) reduction. The kinetics of this reaction using our range of nanomaterials are discussed. It was found that the adsorbents not only reduce the MB, but also remove it completely from the aqueous solution when extracting the nanomaterial by applying an external magnetic field. The MB was desorbed from the nanoparticle surface by acetonitrile, after which the adsorbent could easily be recycled up to 5 times. This reaction was also possible without using NaBH4 as a reducing agent, albeit to a slower extent. The PTA-stabilized nanomaterials prepared with NaBH4 as opposed to sodium citrate, proved to be the best adsorbent for the removal of MB from aqueous solution.

Impact of Carbon N-Doping and Pyridinic-N Content on the Fuel Cell Performance and Durability of Carbon-Supported Pt Nanoparticle Catalysts.

Cathode catalyst layers of proton exchange membrane fuel cells (PEMFCs) typically consist of carbon-supported platinum catalysts with varying weight ratios of proton-conducting ionomers. N-Doping of carbon support materials is proposed to enhance the performance and durability of the cathode layer under operating conditions in a PEMFC. However, a detailed understanding of the contributing N-moieties is missing. Here, we report the successful synthesis and fuel cell implementation of Pt electrocatalysts supported on N-doped carbons, with a focus on the analysis of the N-induced effect on catalyst performance and durability. A customized fluidized bed reduction reactor was used to synthesize highly monodisperse Pt nanoparticles deposited on N-doped carbons (N-C), the catalytic oxygen reduction reaction activity and stability of which matched those of state-of-the-art PEMFC catalysts. Operando high-energy X-ray diffraction experiments were conducted using a fourth generation storage ring; the light of extreme brilliance and coherence allows investigating the impact of N-doping on the degradation behavior of the Pt/N-C catalysts. Tests in liquid electrolytes were compared with tests in membrane electrode assemblies in single-cell PEMFCs. Our analysis refines earlier views on the subject of N-doped carbon catalyst supports: it provides evidence that heteroatom doping and thus the incorporation of defects into the carbon backbone do not mitigate the carbon corrosion during high-potential cycling (1-1.5 V) and, however, can promote the cell performance under usual PEMFC operating conditions (0.6-0.9 V).

High-Performance Surface-Enhanced Raman Scattering Substrates Based on the ZnO/Ag Core-Satellite Nanostructures.

Recently, hierarchical hybrid structures based on the combination of semiconductor micro/nanostructures and noble metal nanoparticles have become a hot research topic in the area of surface-enhanced Raman scattering (SERS). In this work, two core-satellite nanostructures of metal oxide/metal nanoparticles were successfully introduced into SERS substrates, assembling monodispersed small silver nanoparticles (Ag NPs) on large polydispersed ZnO nanospheres (p-ZnO NSs) or monodispersed ZnO nanospheres (m-ZnO NSs) core. The p-ZnO NSs and m-ZnO NSs were synthesized by the pyrolysis method without any template. The Ag NPs were prepared by the thermal evaporation method without any annealing process. An ultralow limit of detection (LOD) of 1 × 10−13 M was achieved in the two core-satellite nanostructures with Rhodamine 6G (R6G) as the probe molecule. Compared with the silicon (Si)/Ag NPs substrate, the two core-satellite nanostructures of Si/p-ZnO NSs/Ag NPs and Si/m-ZnO NSs/Ag NPs substrates have higher enhancement factors (EF) of 2.6 × 108 and 2.5 × 108 for R6G as the probe molecule due to the enhanced electromagnetic field. The two core-satellite nanostructures have great application potential in the low-cost massive production of large-area SERS substrates due to their excellent SERS effect and simple preparation process without any template.

Biocompatible mucoadhesive nanoparticles for brain targeting of ropinirole hydrochloride: Formulations, radiolabeling and biodistribution.

Two nanoformulations with mucoadhesive properties and brain-targeting mechanisms were designed to deliver the anti-Parkinson's drug, ropinirole hydrochloride (RH). In the first formulation, RH and the amphiphilic block copolymer methoxy poly(ethylene glycol)-b-poly(caprolactone) were assembled in a core-shell morphology followed by coating with a mucoadhesive chitosan outer layer producing a multilayer vehicle (MLV). In the second formulation, RH was encapsulated during the polyelectrolyte complexation of two natural polymers, chitosan and alginate producing RH-loaded chitosan-alginate polyelectrolyte (PEC) nanocomplex. Conditions of each formulation were adopted for optimal drug loading. Physico-chemical characterization of the prepared formulations (particle size, polydispersity index and zeta-potential) exhibited stable monodispersed nanoparticles. RH was radiolabeled by I-131 radiotracer in a high-radiochemical yield. Biodistribution and brain targeting of RH from the prepared formulations were studied after administration of 131 I-RH-loaded nanoparticles to albino mice via intranasal and intravenous routs. Elevated brain radioactivity was detected post IN administration of (131 I-RH/PCL-PEG/CS) nanoparticles and (131 I-RH/CS-ALG) nanoparticles comparing with the IN administrated RH solutions (Cmax =2.8 ± 0.3, 2 ± 0.3, 0.93 ± 0.03% radioactivity/g, 1h post administration, respectively). This demonstrated that a relatively high-brain targeting could be achieved via intranasal route of administration of RH-loaded nanoparticles. The proposed models are further potential for application to deliver many other brain-targeting therapeutics.

Catalytically stable monodispersed multi-core Ni-Co nanoparticles encapsulated with SiO2 shells for dry reforming of CH4 with CO2

Enhanced thermal and catalytic stability of monodispersed Ni-Co bimetal nanoparticles with its even size distribution of ~6 nm encapsulated by SiO2 shell (NC@Si) having multicore-shell structures were verified for a harsh dry reforming of methane with CO2 (DRM). The extents of coke formations and aggregations of Ni-Co nanoparticles were dramatically suppressed with positive contributions of oxophilic Co species as well as by their spatial confinement effects. The optimal N8C2@Si with a Ni/Co molar ratio of ~4 revealed a relatively higher CH4 and CO2 conversion of 74.1% and 83.7% at T = 800 °C without significant deactivation phenomena. The original morphologies of the monodispersed Ni-Co nanoparticles were well preserved even after a long-run DRM reaction for 120 h with an insignificant coke formation and active metal aggregation. The superior catalytic activity and stability of the N8C2@Si and N9C1@Si were attributed to the highly-dispersed oxophilic metallic cobalt oxides in the monodispersed stable Ni-Co nanoparticles, which enhanced CO2 adsorption capacity as well as increased thermal stability of the spatially confined Ni-Co nanoparticles with the help of mesoporous SiO2 shell at its optimal aging time less than 4 h. The new multicore-shell structures of the N8C2@Si can effectively suppress the filamentous coke formations as well as minimize the Ni-Co multicore aggregations by stronger metal-SiO2 interactions in the mesoporous protective SiO2 shells.

Anti-microbial and anti-cancer activity of gold nanoparticles phytofabricated using clerodin enriched clerodendrum ethanolic leaf extract

BackgroundSearch for options that can overcome microorganism’s resistance to traditional drugs, has shifted the focus towards plant-based molecules and extracts. Latest developments in plant-based nanomaterials have further expanded the role of plant extracts since nano particle - plant extract combinations are shown to possess enhanced biological activity and reduced toxicity to human cells. In the present study, facile, one-pot synthesis of nearly monodispersed gold nanoparticles was developed using Clerodin enriched Clerodendrum infortunatum ethanolic leaf extract under ambient conditions. The synthesized gold nanoparticles were evaluated for broad spectrum anti-microbial activity as well as compatibility with human peripheral blood mononuclear cells. MethodsClerodin enriched fraction from C. infortunatum leaves ethanol extract was used to synthesize gold nanoparticle from chloroauric acid. Synthesized gold nanoparticles were characterized and tested for broad spectrum anti-microbial activity against Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa using the standard broth dilution method. Cytotoxicity of the gold nanoparticles was evaluated against human monocyte leukemic cells (THP-I) and healthy peripheral blood mononuclear cells. MTT and FACS based Annexin V/FITC-PI assays were used to study its cytotoxic effect. ResultsTEM analysis showed an average diameter of 33 ± 5 nm for the synthesized nanoparticles. EDX validated the presence of elemental Au (98.8%) and confirmed its nano form. Antimicrobial assay of gold nanoparticles showed significant inhibitory effect in all the tested pathogens. Additionally, MTT and Annexin-V/ PI assay demonstrated the cytotoxic activity of the nanoparticles against THP-I cells. Interestingly, nanoparticles did not show cytotoxicity against healthy human peripheral blood mononuclear cells. ConclusionGold nanoparticles generated in an eco-friendlyprocess using Clerodin enriched fractions showed promising broad spectrum antibacterial activity. Simultaneously, they proved themselves to be benign against healthy human cells indicating potential therapeutic applications. Added benefit for the nanoparticles was, they had anti-proliferative effects against human leukemic monocyte cancer (THP-I) cells.

In situ growth of Li4Ti5O12 nanoparticles on Ti3C2Tx MXene for efficient electron transfer as high-rate anode of Li ion battery

How to prepare monodispersed Li4Ti5O12 (LTO) nanoparticles and build effective interface with conductive matrix are significant for its high-rate performance, but still big challenges to be fulfilled well now. Herein, we successfully prepared monodispersed LTO nanoparticles on Ti3C2Tx MXene (M-LTO) in situ through a natural oxidation and hydrothermal lithiation process. The mild oxidation and proper LiOH concentration are proved critical to control the states of final products. Oriented growth was found between LTO and Ti3C2Tx MXene, i.e., LTO [110]//Ti3C2Tx [001], indicating the presence of in-situ interface. It is very effective to facilitates the electron transfer between collector/LTO interface, which exhibited low electron polarization resistance, and helped M-LTO samples achieve higher capacity retention than LTO-Ti3C2Tx mixture and pure LTO. Typically, M-LTO-8 sample delivered a reversible capacity of 137 mAh g−1 at 10 C and over 125 mAh g−1 at a high rate of 50 C, with a capacity retention of 87.5% after 1000 cycles at 10 C. This work highlighted the in-situ oriented growth of LTO from Ti3C2Tx MXene, revealed its advantage for high-rate performance, and provided new insights for high-rate electrode design.

Sustainable synthesis of monodispersed gold nanoparticles from Phoenix dactylifera L. and in vivo anti-diabetic activity on Alloxan induced mice

In the present study, gold nanoparticles biogenically synthesized from Date palm seeds (Phoenix dactylifera L.) were investigated for its anti-diabetic properties. About thirty-two albino mice were selected and 7 days of acclimatization were studied then they were randomly divided into 4 groups (I-IV) of 8 rats each. These groups were intraperitoneally injected with 100 mg/Kg body weight of Alloxan monohydrate. The groups were labeled as a diabetic group, control group, diabetic group treated with standard drug Glibenclamide (100 mg/Kg body weight), and diabetic group treated with AuNPs (100 mg/Kg body weight). This treatment was performed for 28 days via oral administration. The results showed a significant decline in the concentration of their blood glucose level after 28 days of continuous administration of AuNPs. Additionally, AuNPs significantly recovered the damage done to pancreatic, renal, and hepatic tissues in Alloxan induced mice. Hence, AuNPs formed through Phoenix dactylifera L. has appreciable anti-diabetic outcome in preclinical settings.

Importance of the Structural and Physicochemical Properties of Silica Nanoshells in the Photothermal Effect of Silica-Coated Au Nanoparticles Suspensions.

In this work, monodisperse silica-coated gold nanoparticles (NPs) were synthesized and used for obtaining aqueous colloidal dispersions with an optimum relationship between colloidal stability and photothermal activity. The idea behind this design was to produce systems with the advantages of the presence of a silica shell (biocompatibility, potential for surface modification, and protecting effect) with a minimal loss of optical and thermal properties. With this aim, the photothermal properties of NPs with silica shells of different thicknesses were analyzed under conditions of high radiation extinction. By using amorphous, gel-like silica coatings, thicknesses higher than 40 nm could be obtained without an important loss of the light absorption capacity of the colloids and with a significant photothermal response even at low NP concentrations. The effects produced by changes in the solvent and in the NP concentration were also analyzed. The results show that the characteristics of the shell control both, the photothermal effect and the optical properties of the colloidal dispersions. As the presence of a silica shell strongly enhances the possibilities of adding cargo molecules or probes, these colloids can be considered of high interest for biomedical therapies, sensing applications, remote actuation, and other technological applications.