Narrow Results

Nanoparticles (NPs) are promising candidates for different biomedical applications due to their excellent antimicrobial applications. However, the applications become limited due to the higher cost of NP synthesis. In his research work, Hydroxyapatite Nanoparticles (HANPs) have been synthesized in a cost-effective method to apply in biomedical applications. The synthesized HANPs have been characterized by different morphological and antimicrobial characterization methods. Ultraviolet–Visible (UV) spectroscopy was performed and a peak was obtained at 271nm which confirmed the formation of NPs and opened a new door for further analysis. Fourier Transformed Infrared Spectroscopy (FTIR) has been performed and the presence of functional groups such as hydroxides carbonates and phosphates have been identified. Transmission Electron Microscopy (TEM) analysis reveals the circular and smaller shape of the synthesized HANPs. The chemical elements of HA have been identified by EDS analysis. Sharp peaks identified by the X-Ray Diffraction (XRD) analysis confirm the formation of crystals in the synthesized HANPs. An excellent antimicrobial performance which is 99.99% has been obtained from the gram-positive and gram-negative bacterial strains. The obtained results suggest the potentiality of the synthesized HANPs in biomedical applications.

We show that the crystal structure of a substrate can be exploited to drive the anisotropic assembly of colloidal nanoparticles. Pentanethiol-passivated Au particles of ~ 2 nm diameter deposited from toluene onto hydrogen-passivated Si(111) surfaces form linear assemblies (rods) with a narrow width distribution. The rod orientations mirror the substrate symmetry, with a high degree of alignment along principal crystallographic axes of the Si(111) surface. There is a strong preference for anisotropic growth with rod widths substantially more tightly distributed than lengths. Entropic trapping of nanoparticles provides a plausible explanation for the formation of the anisotropic assemblies we observe.

In relation to potential health risks, there is little available information on exposure to aerosols containing nanometer-size particles in work environments in factories producing engineered nanomaterials. We measured the concentrations and size distributions of particles of nanometer-sized to coarse-sized particles in an engineered carbon nanomaterial factory and a titanium dioxide factory. In addition, particles were collected with a quartz fiber filter in the engineered carbon nanomaterial factory, and their morphology was examined by scanning electron microscopy and their carbon composition was examined with a carbon analyzer. In the carbon nanomaterial factory, the particle number increased to more than 10⁵ cm^-3 when a vacuum cleaner was used to clean the inside of the producing device, and the particle number increased for particles with a diameter of about 100 nm compared with the background. This is the only case an increase in particle numbers is observed during this measurement. The emitted particles appear to consist of agglomerates of carbon nanomaterial particles smaller than 100 nm. The major fraction was the EC3 fraction (EC: elemental carbon; combustion at 800°C in a 98:2 He/O₂ atmosphere), which is a minor fraction in diesel engine particulate matter. This suggests that the combustion temperature can be used to differentiate atmospheric particulate matter from engineered carbon material. Personal sampling conducted in addition to stationary measurements in the titanium dioxide factory indicated that stationary measurements can be used to generate representative data on the basis of the particle number but not the particle mass.

Polymer nanocomposites, which contain nanoparticles dispersed in a polymer matrix, provide improved properties at low filler loadings. These materials are already produced commercially, with twin-screw extrusion being the preferred process for compounding the nanoparticles and polymer melts. Several recent studies have demonstrated that nanoparticles can enter the body through inhalation, but the risk assessments for nanoparticle exposures are incomplete. Recently, concerns had been expressed that airborne nanoparticles released during compounding might present significant exposure to extruder operators. To assess the impact of the nanoparticles during twin-screw compounding of nanocomposites, researchers with experience in occupational and environmental health and polymer manufacturing monitored the compounding process for a model nanoalumina-containing nanocomposite using a TSI Fast Mobility Particle Spectrometer (FMPS). FMPS measurements were taken at background locations, source locations, and operators' breathing zones. In parallel to the FMPS real time measurement, airborne nanoparticles were collected using polycarbonate filters fitted with filmed grids driven by a personal air sampling pump. Filter samples were analyzed for particle morphology and elemental composition, and the results were found to be in good agreement with particle measurements by FMPS.

Engineering controls and administrative controls were applied to reduce particle release from the compounding process and other operations in the laboratory. The administrative controls dramatically eliminated nanoparticles in the laboratory air, reducing total concentration by as much as 53 000 particles/cm³. Engineering controls were investigated and significant reductions of particle release were attained. The primary solution to reduce exposure level of nanoalumina is to isolate the releasing source. Overall, the engineering controls and administrative controls were effective in reducing airborne nanoparticle release during compounding.

The present investigation is aimed at the biomedical aspects of nanomaterials in medicine and health sciences. Synthesis of nanomaterials can be categorized into three main sections based on their system designation, viz. nanocolloidal systems, surface modification of the biomaterials at molecular level, and nanodevices. An overview of functionalized nanomaterials, devices, and systems in drug and gene delivery, controlled release systems, molecular imaging and diagnostics, cardiac therapy, dental care, orthopedics, and targeted cancer therapy is presented. We further present some preliminary results of our investigation of biodegradable polymeric nanospheres and nanofibers with significant applications in health and medicine.

Cinobufagin-loaded bovine serum albumin nanoparticles were prepared for treating hepatocellular carcinoma. In this report, cinobufagin-bovine serum albumin-nanoparticles (Cino-BSA-NP) were prepared by an aqueous desolvation process. The physicochemical properties, toxicity, and cancer-related applications of Cino-BSA-NP were investigated. Cino-BSA-NP had a uniform spherical morphology with a particle size in the range of 50–240 nm and an average size of 86.3 nm. The zeta potential of the nanoparticles was -49 mV. The overall embedding ratio was 79.5% and the drug loading was 24.1%. Cino-BSA-NP gave cinobufagin release of up to 53.5% within 3 h, followed by slower controlled release. Cino-BSA-NP inhibited growth of hepatocarcinoma cells in vitro to a similar extent as free cinobufagin, but with a much higher median lethal dose (LD₅₀). Hepatic histomorphological changes indicated that hepatic damage was much less severe with Cino-BSA-NP than with free cinobufagin (2.19 mg/kg). The survival time of nude mice with orthotopic transplantation tumors treated with Cino-BSA-NP was prolonged significantly. The results confirm that Cino-BSA-NP renders cinobufagin completely dispersible in aqueous media, meeting the key requirements for intravenous injection, and show controlled release, thus significantly improving cinobufagin's antitumor activity while reducing its side effects.

This paper reports an approach for enhancing the luminescent properties of Y₂O₃:Eu³⁺ nanophosphors with cellulose, using a liquid phase precursor (LPP) process. The nanosized particles showed a powder X-ray diffraction pattern, corresponding to the reference, and were highly crystalline. The grain sizes of the samples synthesized at 600°C for 1 h were estimated to be approximately 19 nm. The particle sizes of the samples increased with increasing synthesis temperature and the morphology was cleaned and without impurities. In addition, all the samples had a smaller particle size than that of the commercial product. The PL spectrum consisted of weak bands at 581, 587, 593, and 599 nm, corresponding to the ⁵D₀ → ⁷F₁ transition, and sharp peaks with a maximum intensity occurring at approximately 610 nm, due to the ⁵D₀ → ⁷F₂ transition of Eu³⁺. These results suggest that Y₂O₃:Eu³⁺ is a promising alternative red-emitting phosphor for high efficiency resolution display applications.

A simple method has been developed for decorating multi wall carbon nanotubes (MWCNTs) with palladium and silver nanoparticles. In this method, MWCNT was opened and functionalized using nitric and sulfuric acid mixture. Then citric acid was polymerized in the presence of functionalized MWCNT and MWCNT-graft-poly (citric acid) (MWCNT-g-PCA) was obtained. The mixing of MWCNT-g-PCA with metal salts, such as palladium chloride and silver nitrate, leads to encapsulation of metal nanoparticles in the polymeric shell (MWCNT/Pd, AgNPs). The structure of MWCNT/Pd and AgNPs were characterized by usual spectroscopy and microscopy methods. The influence of nanoparticles on the electrical conductivity of MWCNT was also investigated.

Recombinant vault nanoparticles are used as stable nanoscale platforms for controlled self-assembly of various kinds of nanoparticles into the predefined multidimensional architectures. High-yield and uniform discoidal assemblies templated by vaults are constructed from gold nanospheres and quantum dots, while dimeric assemblies are formed from relatively-large gold nanocubes. The vault-templated approach appears to be mainly mediated by the surface and dimensional properties of nanoparticles while less affected by the chemical composition of nanoparticles, making it a universal strategy for fabrication of nanoassemblies with designed properties for potential applications.

A new TiO₂ nanoparticles/nanorods composite electrode was fabricated and applied in dye-sensitized solar cells (DSSCs). The TiO₂ nanorods were obtained by grinding the electrospun TiO₂ nanofibers mechanically. The composite photoanode of dye-sensitized solar cells was fabricated by using TiO₂ nanoparticles (P25) and electrospun TiO₂ nanorods. At the optimized condition, the power conversion efficiency (η) based on a triphenylamine dye (SD2) and a ruthenium dye (N719) are 8.28% and 8.80% under AM 1.5 illumination (100 mW ⋅ cm^-2), respectively. The results show that the electrospun TiO₂ nanorods in the composite photoanode improve the physicochemical properties and enhance the photovoltaic performances of solar cells.

The 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) nanoparticles were prepared by using semibatch reaction crystallization method, and the influencing factors in close relationship with the grain size and crystal morphology control, such as the concentration of reaction system and categories of surfactants, were studied in this paper. The synthesized nano-TATB particles had been characterized by SEM, XRD, thermo gravimetric/differential scanning calorimetric (TG/DSC) and N₂ physisorption. The grain size of TATB particles using nonionic surfactant as the additive ranged from 30 nm to 65 nm with a shape of spheres or ellipsoids. The broadening of the peaks and the weakening of the strength for nano-TATB were observed by XRD analysis. The corrected average particle size of nano-TATB was calculated using the Debye–Scherrer equation and the range was from 18 nm to 50 nm. TG and DSC curves revealed that thermal decomposition of nano-TATB occurred in the range of 361.5°C–385.0°C and its peak temperature was 373.7°C with a decrease of approximately 7°C compared with original TATB. Furthermore, the specific surface area (21.54 m²/g) of nano-TATB was calculated by BET method using N₂ physisorption (at 77°C).

Folate-modified iron ferrite nanoparticles with high doxorubicin loading (FDMP) were developed for dual targeting of tumor cells. Large quantities of doxorubicin and folate ligand were chemically coupled to the synthesized dual-functional magnetic nanoparticles by using the multihand cross-linker poly-L-glutamic acid. FDMP exhibits high drug loading ability, narrow size distribution and pH sensitivity to drug release. The drug loading ratio and the magnetic response can be adjusted by controlling the reactant ratio. FDMP possesses high magnetic-guided ability and exhibits enhanced uptake by folate receptors expressing tumor cells and increased cancer cell cytotoxicity.

Chitosan (CS) is an excellent natural biodegradable and biocompatible polymer for biomedical applications, however, its poor solubility in water or organic solvents limits its applications in drug delivery. In order to resolve this problem, chitosan was modified with acrylonitrile (AN) and arginine (Arg), the modified chitosan (AN–CS–Arg) was characterized by ¹H NMR and Fourier transform infrared (FTIR). The AN–CS–Arg was self-assembled into nanoparticles to encapsulate anticancer drug doxorubicin (DOX). The size and morphology of the blank and drug-loaded AN–CS–Arg (AN–CS–Arg/DOX) nanoparticles were measured by dynamic light scattering (DLS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The mean size of both blank and AN–CS–Arg/DOX nanoparticles were around 50 nm and 170 nm, respectively. The drug-loading content was about 12%. The release profile of AN–CS–Arg/DOX nanoparticles was investigated in vitro, 80% encapsulated DOX could be released within 80 h. The AN–CS–Arg nanoparticles were nontoxic to both NIH 3T3 fibroblasts and HepG2 cancer cells. The cellular uptake of the AN–CS–Arg nanoparticles was trafficked via Confocal Laser Scanning Microscopy and Flow Cytometry, both results showed that the AN–CS–Arg nanoparticles could be internalized in HepG2 cells efficiently. The IC₅₀ of AN–CS–Arg/DOX nanoparticles to HepG2 cancer cells was 10.0 μg/mL. The AN–CS–Arg nanoparticles are potential carriers for anticancer drug delivery.

In this study, rose-like nickel oxide nanoparticles (diameter of 400–500nm) were prepared on indium tin oxide (ITO) glass substrates by a simple electrodeposition in NiSO${}_4\cdot$6H₂O solution. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM) were used for analysis of the NiO nanoparticles. The effects of operating temperature on the sensor response and the response versus gas concentration properties of the NiO nanorose-based sensors were investigated. We determined the operating temperature of the gas sensors to be 230${}^{\circ }$C, considering the proper sensitivity and a rapid response. In addition, gas-sensing characteristics of rose-like NiO nanoparticles to formaldehyde were investigated. It was shown that the sensors exhibited good response ($R_{\mathrm{\text{g}}}$/$R_{\mathrm{\text{a}}}=3.43$) properties to formaldehyde gas at 230${}^{\circ }$C, making them to be promising candidates for practical detectors to formaldehyde gas.

Sulfur-doped SnO₂ nanoparticles with ultrafine sizes have been successfully prepared by a one-pot hydrothermal method. The obtained samples are characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), thermogravimetric (TG), analyzer UV-Vis spectroscopy, photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the doping level of sulfur element as well as the bandgaps of SnO₂ can be controlled to a certain extent by varying the amount of L-cysteine (L-cys). When evaluated as photocatalysts in the degradation of rhodamine B (RhB) and reduction of Cr(VI) under visible light region, the resultant sulfur-doped SnO₂ nanoparticles demonstrate obviously enhanced photocatalytic activities due to the markedly improved visible light response and effective separation of the photo-generated electron–hole pairs.

Hierarchical self-assembling of materials represents one of the most appealing subjects in nanoscience, since bottom-up strategies allow for tailor-made synthesis of functional structures in commodities as well as in living systems. Herein we show that nanorings of ca. 10nm silica nanoparticles without any inorganic metal oxide or organic participant are able to spontaneously self-assemble presenting sophisticated forms and hierarchy. It was observed that after synthesis, silica nanoparticles are chaotically distributed but during storage at ambient conditions they spontaneously form self-assembled aggregates with multiplicity of morphologies when a small amount of water is added in the environment. Detailed description of the morphology of such structures by high resolution transmission electron microscope (HRTEM) is presented together with a discussion about the role of water during their spontaneous formation.

In the present study, a controlled release electrochemical (CRE) technique based on the controlled release of Cu${}^{2+}$ ion from Cu anode in the presence of decanoic acid (HDe) has been used to synthesize Cu(II) decanoate (CuDe₂) complex. The effect of applied voltages (1–10V) and electrolyte concentrations (0.1–2.0M CH₃COONH₄) during the electrolysis on the nanoparticles obtained was studied using TEM. The results reveal that small-sized nanoparticles ($2\pm 1$nm) were obtained by using lowest applied voltage and CH₃COONH₄ concentration (1V and 0.1M, respectively). The smallest nanoparticle obtained was then used in the cytotoxicity study against A549 and HeLa cells. The synthesized complex gives moderate cytotoxic effect on the selected cells (IC${}_{50}=15.85\mu$M and 20.89$\mu$M, respectively) and low cytotoxic effect on normal cells (IMR90). Apoptosis is the mode of cell death based on the apoptosis assay that has been conducted.

Willow catkins as a kind of seasonal biomass are harmful to human health in terms of causing respiratory ailments and skin anaphylaxis every spring. To explore the high-value utilization of willow catkins, in this study, we attempt to develop a kind of tin-based anode materials with willow catkin derived carbon (WCC) as the matrix. A designed solvent-thermal method involving thiourea as stabilizer and acetone–H₂O mixture as solvent has been employed to fabricate SnO₂–WCC composites, which exhibit uniform deposition of well-dispersed SnO₂ nanoparticles on the surface of WCC. As an anode material for lithium-ion batteries (LIBs), the SnO₂–WCC composite delivered a stable discharge capacity of 565mAh g${}^{-1}$ at 100mA g${}^{-1}$ after 70 cycles and a good rate capability of 349mAh g${}^{-1}$ at 1000mA g${}^{-1}$. The high dispersity of SnO₂ nanoparticles and high conductivity of WCC are both believed to contribute to the excellent electrochemical performances. These results suggest the potential of willow catkins derived carbonaceous materials applied in anode materials of LIBs and shed light on the creation of advanced carbon materials from other biomass materials towards energy storage applications.

In order to satisfy the needs of electronic industries for high-reliability joints, different kinds of nanoparticles were incorporated into conventional Pb-free solders to enhance the performance of solder joints by researchers for decades. It is reported that doping certain nanoparticles to the solder can promote the wettability and strength of the solder, refine the grain size of solder and intermetallic compounds, and inhibit IMC layer growth. In this paper, the effects and the corresponding mechanism of nanoparticle addition on the reliability of Sn-based Pb-free solder joints in various conditions are comprehensively analyzed and summarized such as under thermal aging, thermal cycling, thermal shock, electromigration and so on. In addition, directions for future study about the reliability of nanoparticles-doped solder joints were discussed, so as to provide theoretical support for developing high-reliability nanocomposite solder joints.

Nanobiochar exhibits promising applications across a spectrum of fields due to its exceptional physicochemical properties. Ball milling, a prominent nanobiochar synthesis method, is influenced by process factors and biochar pretreatments, yet dominant controls still remain uncertain. In this study, the apple branch bulk biochar (pyrolyzed under ${350}^{\circ }$C) was ball milled under different milling speeds, ball-to-powder mass ratios, and milling durations to investigate the optimal process parameter combinations for ball milling method. Then, we evaluated the impact of pyrolysis temperature and pretreatment temperature of bulk biochar on ball milling effect using optimized parameter combinations. Subsequently, the physicochemical properties of the bulk biochar and nanobiochar were measured. The results showed that high speed with low ball-to-powder mass ratio, low speed with high ball-to-powder mass ratio, and high pyrolysis temperature could significantly decrease the particle sizes of nanobiochar. Ball milling duration and pretreatment temperature had no significant effect on the particle sizes of biochar. The optimal combination of the rotational speed, ball-to-powder mass ratio and milling duration was 400 RPM, 100:1, 2h and 700 RPM, 20:1, 2h. The bulk biochar pyrolyzed at ${550}^{\circ }$C could be milled into biochar nanoparticles with an average particle size smaller than 100nm via above parameters. Nanobiochar shows improved properties such as specific surface area, cation exchange capacity, and surface functional groups over bulk biochar. This study provides a scientific basis for the widespread application of ball milling in the field of preparing nanobiochar.