Effect of Mo doping in NiO nanoparticles for structural modification and its efficiency for antioxidant, antibacterial applications

An octahedral metal oxide nanoparticle-based dual-signal sensing platform for simultaneous detection of histidine and lysine in human blood plasma and urine

Histidine and lysine serve as essential amino acids in physiological processes and biomarkers for specific diseases, requiring precise detection methods in a variety of samples. This study presents an affordable single colorimetric probe that employs nickel oxide nanoparticles (NiONPs) as an artificial enzyme to detect histidine and lysine, improving conventional analytical limitations. The characterization of NiONPs was executed using SEM-EDX, FE-SEM, FTIR and XRD. The NiONPs demonstrated peroxidase-like catalytic activity on the conversion of TMB to oxidized TMB (oxTMB) in the presence of H2O2, utilizing optimization parameters like pH value (3), TMB concentration (10 mM), H2O2 concentration (60 mM), and incubation time (18 min). The study revealed that Ni and O atoms are present on the surface of NiONPs, allowing for specific interactions with essential amino acids and temporarily hindering the catalytic activity of oxidized TMB. The method exhibited a low limit of detection (LOD) of 0.07 μM (10-100 μM) for histidine and 1.1 μM (15-150 μM) for lysine with good stability. The proposed strategy was validated with urine and plasma samples, yielding favorable recoveries of 93.6-98.2% in urine and 90.5-96.0% in plasma for histidine and 91.2-94.8% in urine and 88.4-93.3% in plasma for lysine, supporting its selectivity, feasibility, and reliability for practical applications. In the future, this methodology will facilitate the integration of histidine and lysine detection into microfluidic systems using NiONPs as a colorimetric probe.

Facile green synthesis of silver doped NiO nanoparticles using aloe vera latex for efficient energy storage and photocatalytic applications

Herein, we report the biosynthesis of pure NiO and NiO nanoparticles doped with Silver (Ag@NiO NPs) 2, 4, 6, and 8 mol% from aloe vera extract by solution combustion method at 400 °C and calcined at 500 °C for 3 h. By utilizing silver-doped NiO nanoparticles synthesized with Aloe Vera latex, which not only enhances the material's properties but also promotes environmentally friendly fabrication methods. The morphological, structural elemental compositions were analysed through SEM, HRTEM, SAED, XRD and EDAX. The band gap was determined as 2.48, 2.57, 2.58, 2.60, and 2.62 eV for pure NiO, 2-8% Silver doped NiO using Kubelka-Munk plot. The photocatalytic potential of the 6 % Ag doped NiO has been explored by assessing their effectiveness in degrading fast blue (FB) dye, demonstrating significant activity at 605 nm. Remarkably, with 120 min of UV radiation, the FB dye reaches an impressive photodegradation rate of 98 %, making the dye nearly colorless. The green synthesized NPs were tested in 1 M KOH to investigate their supercapacitor performance as an effective material for electrode. The Cyclic Voltammetry (CV), the Galvanostatic charge-discharge (GCD), and the Electrochemical impedance spectroscopy (EIS) studies were conducted to determine the materials' electrochemical activity. The GCD study for 6 mol% Ag@NiO in a 3-electrode system shows a capacitance of 535 F g-1 at a current density of 1 Ag-1. 6 mol% Ag@NiO modified electrode shows excellent long-term stability, retention of more than 92 % of its initial capacitance after the operation of 2000 cycles. The important outcome of this work lies in multifunctional application of the as-synthesized materials, demonstrating their effectiveness for both efficient energy storage and improved photocatalytic performance, paving the way for sustainable and multifunctional devices.

Gelatin/PLA-loaded gold nanocomposites synthesis using Syzygium cumini fruit extract and their antioxidant, antibacterial, anti-inflammatory, antidiabetic and anti-Alzheimer's activities

Nanotechnology has experienced significant advancements, attracting considerable attention in various biomedical applications. This innovative study synthesizes and characterizes Ge/PLA/AuNCs (gelatin/PLA/gold nanocomposites) using Syzygium cumini extract to evaluate their various biomedical applications. The UV-Visible spectroscopy results in an absorption peak at 534 nm were primarily confirmed by Ge/PLA/AuNCs synthesis. The FTIR spectrum showed various functional groups and the XRD patterns confirmed the crystalline shape and structure of nanocomposites. The FESEM and HRTEM results showed a oval shape of Ge/PLA/AuNCs with an average particle size of 21 nm. The Ge/PLA/AuNC's remarkable antioxidant activity, as evidenced by DPPH (70.84 ± 1.64%), ABTS activity (86.17 ± 1.96%), and reducing power activity (78.42 ± 1.48%) at a concentration of 100 μg/mL was observed. The zone of inhibition against Staphylococcus aureus (19.45 ± 0.89 mm) and Echericia coli (20.83 ± 0.97 mm) revealed the excellent antibacterial activity of Ge/PLA/AuNCs. The anti-diabetic activity of Ge/PLA/AuNCs was supported by inhibition of α-amylase (82.56 ± 1.49%) and α-glucosidase (80.27 ± 1.57%). The anti-Alzheimer activity was confirmed by inhibition of the AChE (76.37 ± 1.18%) and BChE (85.94 ± 1.38%) enzymes. In vivo studies of zebrafish embryos showed that Ge/PLA/AuNCs have excellent biocompatibility and nontoxicity. The SH-SY5Y cell line study demonstrated improved cell viability (95.27 ± 1.62%) and enhanced neuronal cell growth following Ge/PLA/AuNCs treatment. In conclusion, the present study highlights the cost-effective and non-toxic properties of Ge/PLA/AuNCs. Furthermore, it presents an attractive and promising approach for various future biomedical applications.

Designing copper-doped zinc oxide nanoparticle by tobacco stem extract-mediated green synthesis for solar cell efficiency and photocatalytic degradation of methylene blue

This study presents the green synthesis of copper-doped zinc oxide (Cu-doped ZnO) nanoparticles using tobacco stem (TS) extract. The environmentally friendly synthesis method ensures distinct features, high efficiency, and applicability in various fields, particularly in solar cell technology and photocatalytic applications. ZnO nanostructures are investigated due to their unique properties, cost-effectiveness, and broad range of applications. The nanoparticles are synthesized with varying Cu concentrations, and their structural, morphological, and compositional characteristics are thoroughly analyzed. The Cu-doped ZnO nanoparticles exhibit improved properties, such as increased surface area and reduced particle size, attributed to the incorporation of Cu dopants. The green synthesis approach using TS extract serves as a stabilizing agent and avoids the toxicity associated with chemical methods. Characterization techniques including SEM, TEM, EDX, FTIR, and XRD confirm the successful synthesis of the nanoparticles. Photocatalytic degradation studies reveal that the 5% Cu-doped ZnO exhibits the highest photocatalytic activity against methylene blue, attributed to synergistic effects between Cu and ZnO, including oxygen vacancy and electron-hole pair recombination rate suppression. The photocatalytic mechanism involves the generation of superoxide and hydroxyl radicals, leading to methylene blue degradation. Furthermore, the Cu-doped ZnO nanoparticles demonstrate promising photovoltaic performance, with the optimal efficiency observed at a 5% Cu concentration. The study suggests that Cu-doped ZnO has the potential to enhance solar cell efficiency and could serve as an alternative material in solar cell applications. Future research should focus on refining Cu-doped ZnO for further improvements in solar energy conversion efficiency.

Silver sulphide nanoparticles (Ag2SNPs) synthesized using Phyllanthus emblica fruit extract for enhanced antibacterial and antioxidant properties

In this study, silver sulfide nanoparticles (Ag2SNP's) were successfully produced by using fruit extracts of Phyllanthus emblica. UV-vis, FTIR, XRD with SEM and EDX techniques were used for the synthesis process and for characterization of the resulting nanostructures. According to the findings, the fabricated nanostructure had a monoclinic crystal structure, measuring 44 nm in grain size, and its strain was 1.82 × 10-3. As revealed by SEM analysis, the synthesized nanostructure consists of irregular spherical and triangular shapes. The presence of silver (Ag) and sulfur (S) was also confirmed through EDX spectra. Furthermore, Ag2S nanoparticles were tested for their ability to effectively inhibit gram-positive and gram-negative bacterial growth. As a result of this study, it was clearly demonstrated that Ag2S nanoparticles possess powerful antibacterial properties, particularly when it came to inhibiting Escherichia coli growth. Ag2S nanoparticles had high total H2O2 and flavonoid concentrations and the greatest overall antioxidant activity, according to the evaluation of antioxidant activity of the samples. The results obtained from the P. emblica fruit extract were followed by those obtained from Ag2S nanoparticles were reported in detail. RESEARCH HIGHLIGHTS: Innovative Ag2SNP synthesis using Phyllanthus emblica fruit extract. SEM with EDX revealed a monoclinic crystal structure with a grain size of 44 nm and a strain of 1.82 × 10-3. Many of these applications are demonstrated by the potential of Ag2SNPs to treat and combat bacteria, particularly Escherichia coli. A peak at 653 cm-1 indicates the presence of primary sulfide aliphatic C-S extension vibrations. The abundant H2O2 and NO2 found in P. emblica nanocomposites make them potent antioxidants.

Enhanced photocatalytic and electrochemical performance of hydrothermally prepared NiO-doped Co nanocomposites

In this study, we synthesize nanostructured nickel oxide (NiO) and doped cobalt (Co) by combining nickel(II) chloride hexahydrate (NiCl2.6H2O) and sodium hydroxide (NaOH) as initial substances. We analyzed the characteristics of the product nanostructures, including their structure, optical properties, and magnetic properties, using various techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet absorption spectroscopy (UV-Vis), Fourier transform infrared (FTIR) spectroscopy, and vibrating sample magnetometers (VSM). The NiO nanoparticles doped with Co showed photocatalytic activity in degrading methylene blue (MB) dye in aqueous solutions. We calculated the degradation efficiencies by analyzing the UV-Vis absorption spectra at the dye's absorption wavelength of 664 nm. It was observed that the NiO-doped Co nanoparticles facilitated enhanced recombination and migration of active elements, which led to more effective degradation of organic dyes during photocatalysis. We also assessed the electrochemical properties of the materials using cyclic voltammetry (CV) and impedance spectroscopy in a 1 mol% NaOH solution. The NiO-modified electrode exhibited poor voltammogram performance due to insufficient contact between nanoparticles and the electrolyte solution. In contrast, the uncapped NiO's oxidation and reduction cyclic voltammograms displayed redox peaks at 0.36 and 0.30 V, respectively.

Molybdenum nanoparticles as a potential topical medication for alopecia treatment through antioxidant pathways that differ from minoxidil

BACKGROUND

Hair loss is a common dermatological condition including various types such as alopecia areata, androgenetic alopecia, etc. Minoxidil is a topical medication used for treating hair loss, which is effective for various types of alopecia. However, minoxidil has limitations in treating hair loss, such as slow onset of action and low efficacy, and it cannot effectively inhibit one of the major pathogenic factors of hair loss - excessive oxidative stress.

METHODS

Transition metal elements with rapid electron transfer, such as molybdenum, have been extensively studied and applied for inhibiting oxidative stress. We established a mouse model for hair growth and intervened with nano-sized molybdenum, minoxidil, and a combination of both. The physicochemical properties of nano-sized molybdenum enabled it to mediate oxidative stress more quickly.

RESULTS

The results showed that nano-sized molybdenum can accelerate hair growth, increase the number of local hair follicles, and reduce the expression of oxidative stress-related molecules such as iNOS, COX2, and androgen receptors. The combination of nano-sized molybdenum and minoxidil showed an additive effect in promoting hair growth.

CONCLUSION

Our findings suggest that nano-sized molybdenum might be a potential topical medication for treating hair loss by inhibiting the oxidative stress pathway. Nano-sized molybdenum, alone or in combination with minoxidil, could be a promising therapeutic approach for patients with hair loss, particularly those who do not respond well to current treatments. Further clinical studies are warranted to confirm the efficacy and safety of this novel treatment.

Antibacterial Activity of Molybdenum Oxide-Polyacrylonitrile Composite Membrane with Fast Silver Ion Reduction

The development of hybrid composite antibacterial agents for wound dressing has garnered significant attention due to their remarkable antibacterial efficacy and their potential to mitigate microbial resistance. In this study, we present an approach to designing and fabricating wound dressing membranes, utilizing molybdenum oxide-polyacrylonitrile (MoO3/PAN) hybrid composites through electrospinning. Subsequently, we enhanced the membrane's effectiveness by introducing silver (Ag@MoO3/PAN) into the matrix via a rapid (within one min) green synthesis method under UV irradiation. Initially, we discuss the morphological characteristics and structural attributes of the resulting membranes. Subsequent investigations explore the antibacterial mechanisms of both MoO3 and Ag+, revealing that the incorporation of silver substantially enhanced antibacterial activity. Additionally, we elucidate the surface properties, noting that the introduction of silver increases the surface area of the composite membrane by 25.89% compared with the pristine MoO3/PAN membrane. Furthermore, we observe a 9% reduction in the water contact angle (WCA) for the Ag@MoO3/PAN membrane, indicating improved hydrophilicity. Finally, we analyze the release behavior of the Ag@MoO3/PAN membrane. Our findings demonstrate an initial burst release within the first 7 h, followed by a controlled and sustained release pattern over a period of 7 days.

Long-Term Stable Complementary Electrochromic Device Based on WO3 Working Electrode and NiO-Pt Counter Electrode

Complementary electrochromic devices (ECDs) composed of WO₃ and NiO electrodes have wide applications in smart windows. However, they have poor cycling stability due to ion-trapping and charge mismatch between electrodes, which limits their practical application. In this work, we introduce a partially covered counter electrode (CE) composed of NiO and Pt to achieve good stability and overcome the charge mismatch based on our structure of electrochromic electrode/Redox/catalytic counter electrode (ECM/Redox/CCE). The device is assembled using a NiO-Pt counter electrode with WO₃ as the working electrode, and PC/LiClO₄ containing a tetramethylthiourea/tetramethylformaminium disulfide (TMTU/TMFDS²⁺) redox couple as the electrolyte. The partially covered NiO-Pt CE-based ECD exhibits excellent EC performance, including a large optical modulation of 68.2% at 603 nm, rapid switching times of 5.3 s (coloring) and 12.8 s (bleaching), and a high coloration efficiency of 89.6 cm²·C^-1. In addition, the ECD achieves a good stability of 10,000 cycles, which is promising for practical application. These findings suggest that the structure of ECC/Redox/CCE could overcome the charge mismatch problem. Moreover, Pt could enhance the Redox couple's electrochemical activity for achieving high stability. This research provides a promising approach for the design of long-term stable complementary electrochromic devices.

Effect of the molar ratio of (Ni2+ and Fe3+) on the magnetic, optical and antibacterial properties of ternary metal oxide CdO-NiO-Fe2O3 nanocomposites

In this work, the effect of the molar ratio of (Ni²⁺ and Fe³⁺) on the properties of CdO-NiO-Fe₂O₃ nanocomposites was investigated. The synthesis of CdO-NiO-Fe₂O₃ nanocomposites was carried out by self-combustion. XRD, UV-Vis, PL and VSM were used to describe the physical properties of the materials. The results showed significant progress in structural and optical properties supporting antibacterial activity. For all samples, the particle size decreased from 28.96 to 24.95 nm with increasing Ni²⁺ content and decreasing Fe³⁺ content, as shown by the XRD pattern, which also shows the crystal structure of cubic CdO, cubic NiO, and cubic γ-Fe₂O₃ spinel. The Ni²⁺ and Fe³⁺ contents in the CdO-NiO-Fe₂O₃ nanocomposites have also been shown to enhance the ferromagnetic properties. Due to the significant coupling between Fe₂O₃ and NiO, the coercivity H_c values of the samples increase from 66.4 to 266 Oe. The potential of the nanocomposites for antibacterial activity was investigated against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli, and Moraxella catarrhalis) bacteria. Comparison of P. aeruginosa with E. coli, S. aureus and M. catarrhalis showed that it has a stronger antibacterial activity with a ZOI of 25 mm.