Current Nanoscience - Current Issue

Rice husk is an important agricultural waste that contains organic mass and bio-silica. Although some rice husks have been used as fuel, animal food, filler for wine fermentation, and fertilizer, the majority are discarded as agricultural waste, which does great harm to the environment. The conversion of rice husk to silicon carbide (SiC)-based materials satisfies the demand for the reutilization of solid wastes.

The article reviews recent progress and patents on the SiC-based materials from rice husk. The possible development directions of the SiC-based materials from rice husks are also analyzed.

SiC materials with different morphologies, including microscale and nanoscale particles, nanoscale whiskers, and nanowires, can be prepared by high-temperature carbothermal reduction reaction from rice husk at the temperature of 1200-1800°C, reaction time of 0.5-8 h, respectively. SiC-based composites, including SiC nanowires/C, Al/SiC, SiC/Si3N4, and SiC/Al2O3, can be obtained using rice husk as main source materials at 800-1800°C. SiC-based materials exhibit great application potential in the fields of absorbents, optical devices, mechanical products, photocatalysts, semiconductors, and Li-ion batteries.

The low cost of preparing SiC-based materials from rice husk, combining them with different compositions, and exploring new applications are important research directions in the future.

Heavy metal contamination of food and the environment is a major concern worldwide. Conventional detection techniques like atomic absorption spectroscopy (AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) have limitations including high costs and insufficient sensitivity. Electrochemical sensors based on carbon nanomaterials have emerged as an attractive alternative for rapid, affordable, and ultrasensitive heavy metal analysis.

This review summarizes recent advances in using carbon nanomaterials like ordered mesoporous carbon, carbon nanotubes, graphene and carbon dots for electrochemical sensing of toxic heavy metals. Synthesis methods, characterization techniques, functionalization strategies and detection mechanisms are discussed.

High surface area, electrical conductivity and electrocatalytic activity of carbon nanomaterials enable preconcentration of metal ions and signal amplification at electrode interfaces. This results in remarkably low detection limits down to parts per trillion levels. Functionalization with metal nanoparticles, molecularly imprinted polymers and other nanocomposites further improves sensor selectivity and sensitivity. These sensors have been applied for the quantitative detection of arsenic, mercury, lead, cadmium, chromium, and other toxic metals in lab samples.

Electrochemical sensors based on carbon nanotubes, graphene, mesoporous carbon, and carbon dots are rapidly emerging as an ultrasensitive, cost-effective alternative to conventional techniques for on-site screening of heavy metal contamination in food and environment. Further validation using real-world samples and integration into portable field testing kits can enable widespread deployment.

Electrochemical oxidation of Alizarin Yellow R (AYR) was investigated on Ytterbium (Yb) doped Ti/PbO2 electrodes prepared by an electrodeposition method.

The etching of the Ti sheet by using a mixed acid of H2SO4 and TA (volume ratio= 2: 1) for 50 min at 100°C could produce a suitable interface for further modification. The morphologies, composition, and electrochemical properties of Yb doping on the electrode were characterized by SEM (Scanning Electron Microscopy), EDS (Energy-Dispersive Spectroscopy), Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The introduction of an appropriate intermediate layer, Zr-SnO2, was performed. We also tried to fabricate Ytterbium (Yb) doped Ti/Zr-SnO2/PbO2 electrodes by an electrodeposition method on the intermediate layer of Zr-SnO2. The surface morphology of the Ti/Zr-SnO2/PbO2 electrode was changed due to the Yb doping, which affected the electrocatalytic activity of the modified electrode.

The developed Yb-doped Ti/Zr-SnO2/PbO2 electrode showed improved removal efficiencies toward AYR.

The effects of current density and initial AYR concentration on the electrochemical oxidation of AYR by Yb-doped Ti/Zr-SnO2/PbO2 were investigated. The removal rate of AYR was 97.3% in 180 min under the conditions of the current density of 60 mA/cm², initial AYR concentration of 50.0 mg L^-1, and Na2SO4 concentration of 0.10 mol L^-1.

The aim of this study was to synthesize two positively charged surfactants Stearoylcholine and Oleoylcholine from choline or vitamin B4, saturated and mono-unsaturated fatty acids to modify solid lipid nanoparticles (SLNs) in order to enhance cancer cell uptake.

These surfactants were synthesized by using the esterification method and then SLN formulations of unmodified and modified SLNs containing docetaxel were prepared by emulsification technique. Cytotoxicity of the SLNs was investigated in A549 and MCF7 cancer cells and their cell uptake was assessed by using fluorescent microscope and flow cytometry.

The results of our study revealed that SLNs pose a mean particle size range of 69-133 nm with spherical morphology. In vitro release study demonstrated a slow-release pattern for all three kinds of DTX-loaded SLNs. Stearoylcholine-containing SLNs showed the highest cytotoxic effect on both cells while cytotoxicity of Oleoylcholine SLNs exhibited a dose-dependent manner which may be due to the effect of saturated and mono-unsaturated parts of surfactants. According to flow cytometric analysis, OC and SC containing SLNs showed the highest uptake into A549 and MCF7 cells, respectively.

In conclusion, choline-based surfactants could effectively increase the A549 and MCF7 uptake of modified SLNs, which may be due to cationic surface, choline transporters, and special receptors and mediators.

Carbon nanotube films are utilized in various fields, particularly electric heating, owing to their exceptional thermal and electrical properties. However, quantitative research on the electrothermal characteristics of carbon nanotube film is insufficient, and glass fiber-reinforced epoxy-resin composites prepared through the electrothermal method of carbon nanotube films (i.e., the out-of-autoclave technique) have not yet been reported.

Herein, according to a mathematical model and experimental demonstration, a quantitative relationship, T = T0 + (t/L²)·(V²σ)·(1/αw), was proposed to explain the electrothermal properties of carbon nanotube films. Glass fiber-reinforced composites with an outstanding tensile strength of 535.6 MPa and an elongation-at-break of 1.6% were prepared through the out-of-autoclave technique using the designed carbon nanotube film.

The composites outperformed previous mechanical composites in terms of energy consumption. Experimental investigations and molecular simulations revealed the mechanical mechanisms of the composites.

These findings quantitatively revealed the electrothermal properties of carbon nanotube films, advancing their application in the out-of-autoclave manufacturing of high-performance resin-matrix composites.

It has become essential to look into alternatives that effectively stop bacterial infections due to the exponential rise in antibiotic resistance. The field of nanotechnology has made significant strides in development by surmounting obstacles that have impeded success and advancement in other fields. Nanoparticles (NPs) are the key component in the burgeoning field of nanotechnology.

Cyclamen libanoticum leaf extract (CLE) was used as a reducing and capping agent, with silver nitrate (AgNO3) solution as a precursor for synthesizing silver nanoparticles (CLE-AgNPs). This study aimed to generate green silver nanoparticles (AgNPs) and assess their antioxidant and antibacterial capacities.

CLE-AgNPs were characterized utilizing UV–vis spectrometry, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and photoluminescence (PL). Using the radical scavenging assay 2,2-diphenyl-1-picrylhydrazyl (DPPH), the antioxidant activity of CLE-AgNPs was evaluated. Several assays were employed to examine the antibacterial effect of CLE-AgNPs against various gram-positive and negative bacteria.

Upon analysis, the synthesis revealed 17 nm face-centered cubic CLE-AgNPs (λmax= 431 nm). CLE-AgNPs manifested noticeable antioxidant activity and prominent inhibitory effects on the tested bacteria. The minimum inhibitory concentration (MIC) of the CLE-AgNPs was 31.25 µg/mL for the eight bacterial species. Besides, the results revealed that CLE-AgNPs effectively suppressed the development of bacterial biofilms and could eradicate them.

The present investigation introduced Cyclamen libanoticum as a novel bioresource into green chemistry to produce AgNPs with antibacterial and antioxidant capabilities.

The development of cost-effective and efficient catalysts plays a pivotal role in the realization of hydrogen production through electrochemical water splitting.

In this study, two-dimensional NiCo2S4 nanosheets were synthesized using a hydrothermal method followed by a sulfidation process.

The resulting materials were thoroughly characterized to understand their morphology and structure. The findings indicate that the NiCo2S4 nanosheets exhibit exceptional electrical conductivity and a high density of pores, which facilitate electrolyte infiltration and interfacial charge transfer during electrochemical reactions. Furthermore, the incorporation of S²⁻ modulates the electronic structure of metal ions, reducing the oxidation potential of metal sites and promoting the surface reconstruction of the electrode to form active species. Electrochemical tests conducted in a 1 M KOH solution using the synthesized catalyst as the working electrode demonstrate an overpotential of merely 280 mV and 300 mV at a current density of 20 mA cm⁻² and 40 mA cm^-2, respectively, which are much lower than those of NiCo-LDH electrodes (360 mV and 410 mV).

Furthermore, the NiCo2S4 electrode delivers a remarkably low Tafel slope of 47.9 mV dec⁻¹. This investigation presents a novel approach to the development of efficient transition metal-based electrocatalysts.

Gouty arthritis, characterized by excruciating pain and discomfort, poses a significant burden on patients. While nanomedicines have shown promise in addressing this ailment, their complicated synthesis processes often involve potentially toxic procedures, contributing to adverse side effects in disease management.

In this study, we introduce a straightforward and elegant solution by utilizing easily prepared gold platinum (AuPt) nanoparticles for the treatment of gouty arthritis. The synthesis of these nanoparticles involves the use of gold and platinum precursors in conjunction with NaBH4, simplifying the manufacturing process. Experimental models of gout were established in both in vivo and in vitro settings through lipopolysaccharide and monosodium urate crystal induction.

Our findings revealed that AuPt nanoparticles exhibited potent anti-inflammatory effects against gout. This effect was attributed to their ability to activate the Nrf2/HO-1 pathway, resulting in pain alleviation and the inhibition of inflammation, ultimately leading to the reduction of joint edema. With their uncomplicated synthesis and promising therapeutic potential, these simply prepared AuPt nanoparticles emerge as a compelling candidate for pharmaceutical intervention in the treatment of gouty arthritis.

This approach not only holds the promise of delivering effective relief to patients but also minimizes the risk of unwanted side effects associated with complex nanomedicine synthesis processes.