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Emission of greenhouse gases and infectious diseases caused by improper agro-waste disposal has gained significant attention in recent years. To overcome these hurdles, agro-waste can be valorized into valuable bioactive compounds that act as reducing or stabilizing agents in the synthesis of nanomaterials. Herein, we report a simple circular approach using Citrus reticulata Blanco (C. reticulata) waste (peel powder/aqueous extract) as green reducing and capping/stabilizing agents and Zn nitrate/acetate precursors to synthesize ZnO nanoparticles (NPs) with efficient antimicrobial and photocatalytic activities. The obtained NPs crystallized in a hexagonal wurtzite structure and differed clearly in their morphology. UV-vis analysis of the nanoparticles showed a characteristic broad absorption band between 330 and 414 nm, belonging to ZnO NPs. Fourier transform infrared (FTIR) spectroscopy of ZnO NPs exhibited a Zn–O band close to 450 cm−1. The band gap values were in the range of 2.84-3.14 eV depending on the precursor and agent used. The crystallite size obtained from size-strain plots from measured XRD patterns was between 7 and 26 nm, with the strain between 16 and 4%. The high crystalline nature of obtained ZnO NPs was confirmed by clear ring diffraction patterns and d-spacing values of the observed lattice fringes. ZnNPeelMan_400 and ZnNExtrMan have shown good stability as the Zeta potential was found to be around -20 mV and reduced particle aggregation. Photoluminescence analysis revealed different defects belonging to oxygen vacancies (VO+ and VO++) and zinc interstitial (Zni) sites. The presence of oxygen vacancies on the surface of ZnAcExtrMan_400 and ZnAcPeelMan_400 increased antimicrobial activity, specifically against gram-negative bacteria Escherichia coli (E.coli) and Salmonella enteritidis (S. enteritidis). ZnNextrMan with a minimal inhibitory concentration of 0.156 mg/ml was more effective against gram-positive bacteria, Staphylococcus aureus (S. aureu

In this study, we propose an eco-friendly method for synthesizing cerium tungstate nanoparticles using hydrothermal techniques. We used scanning, transmission electron microscopy, and X-ray diffraction to analyze the morphology of the synthesized nanoparticles. The results showed that the synthesized nanoparticles were uniform and highly crystalline, with a particle size of about 50 nm. The electrocatalytic properties of the nanoparticles were then investigated using cyclic voltammetry and electrochemical impedance spectroscopy. We further used the synthesized nanoparticles to develop an electrochemical sensor based on a carbon paste electrode that can detect hydroquinone. By optimizing the differential pulse voltammetric method, a wide linearity range of 0.4 to 45 µM and a low detection limit of 0.06 µM were obtained. The developed sensor also expressed excellent repeatability (RSD up to 3.8%) and reproducibility (RSD below 5%). Interferences had an insignificant impact on the determination of analytes, making it possible to use this method for monitoring hydroquinone concentrations in tap water. This study introduces a new approach to the chemistry of materials and the environment and demonstrates that a careful selection of components can lead to new horizons in analytical chemistry.

Emission of greenhouse gases and infectious diseases caused by improper agro-waste disposal has gained significant attention in recent years. To overcome these hurdles, agro-waste can be valorized into valuable bioactive compounds that act as reducing or stabilizing agents in the synthesis of nanomaterials. Herein, we report a simple circular approach using Citrus reticulata Blanco (C. reticulata) waste (peel powder/aqueous extract) as green reducing and capping/stabilizing agents and Zn nitrate/acetate precursors to synthesize ZnO nanoparticles (NPs) with efficient antimicrobial and photocatalytic activities. The obtained NPs crystallized in a hexagonal wurtzite structure and differed clearly in their morphology. UV-vis analysis of the nanoparticles showed a characteristic broad absorption band between 330 and 414 nm belonging to ZnO NPs. Fourier transform infrared (FTIR) spectroscopy of ZnO NPs exhibited a Zn-O band close to 450 cm-1. The band gap values were in the range of 2.84-3.14 eV depending on the precursor and agent used. The crystallite size obtained from size-strain plots from measured XRD patterns was between 7 and 26 nm, with strain between 16 and 4%. The highly crystalline nature of obtained ZnO NPs was confirmed by clear ring diffraction patterns and d-spacing values of the observed lattice fringes. ZnNPeelMan_400 and ZnNExtrMan showed good stability, as the zeta potential was found to be around −20 mV, and reduced particle aggregation. Photoluminescence analysis revealed different defects belonging to oxygen vacancies (VO+ and VO+2) and zinc interstitial (Zni) sites. The presence of oxygen vacancies on the surface of ZnAcExtrMan_400 and ZnAcPeelMan_400 increased antimicrobial activity, specifically against Gram-negative bacteria Escherichia coli (E. coli) and Salmonella enteritidis (S. enteritidis). ZnNExtrMan with a minimal inhibitory concentration of 0.156 mg/mL was more effective against Gram-positive bacteria Staphylococcus aureus (S. aureus), r

When magnetic nanoparticles (MNPs) are placed in an alternating (ac) magnetic field, they absorb the energy of the field and convert it into heat, which causes a temperature change in the system. Consequently, it makes them suitable for cancer treatment with magnetic hyperthymia.

In this paper, electrochemical degradation of Reactive Black 5 (RB5) textile azo dye was examined in regard to different synthesis procedures for making PbO2–graphitic carbon nitride (g-C3N4) electrode. The reaction of Pb(OH)−3 with ClO− in the presence of different surfactants, i.e., cetyltrimethylammonium bromide (CTAB) and tetrabutylammonium phosphate (TBAP), under conventional conditions, resulted in the formation of PbO2 with varying morphology. The obtained materials were combined with g-C3N4 for the preparation of the final composite materials, which were then characterized morphologically and electrochemically. After optimizing the degradation method, it was shown that an anode comprising a steel electrode coated with the composite of PbO2 synthesized using CTAB as template and g-C3N4, and using 0.15 M Na2SO4 as the supporting electrolyte, gave the best performance for RB5 dye removal from a 35 mg/L solution. The treatment duration was 60 min, applying a current of 0.17 A (electrode surface 4 cm2, current density of 42.5 mA/cm2), while the initial pH of the testing solution was 2. The reusability and longevity of the electrode surface (which showed no significant change in activity throughout the study) may suggest that this approach is a promising candidate for wastewater treatment and pollutant removal.

In this work, a modified bismuth-oxychloride (BiOCl) carbon paste electrode was prepared for the detection of quinine. BiOCl nanoparticles were synthesized by the chemical coprecipitation method. The electrochemical properties of quinine at this electrode were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and differential pulse voltammetry (DPV). In addition, electrochemical impedance spectroscopy (EIS), inductively coupled plasma–optical emission spectrometry (ICP-OES), transmission and scanning electron microscopy (TEM and SEM) and X-ray diffraction (XRD) were used to characterize the synthesized materials. The prepared electrode showed better electrocatalytic response than the bare carbon paste electrode.

A series of MgxFe3-xO4 (x=0, 0.1, 0.2, 0.4, 0.6, 0.8, and 1) magnetic nanoparticles (MNP) were synthesized by a two-step procedure, a co-precipitation method followed by hydrothermal treatment in a microwave field. The MNP are single-core, with crystallite size gradually decreasing from 15.5(3) up to 2.5(3) nm with an increase ofx. TEM images show pseudospherical log-normally distributed particles with an average particle diameter of 19.8 nm and a polydispersity index of 26.1% for magnetite. The particle diameter decreases with the increase of magnesium (x) in the formula unit. The colloidal stability of MNP was achieved by their surface modification with citric acid (CA), oleic acid (OA) and polyethylene glycol (PEG). The cytotoxic activity of uncoated and coated Mg0.6Fe2.4O4 was tested against target malignant cells (HeLa, LC174, A549) and normal MRC5 cells. The investigated MNP show moderate cytotoxic activity against the tested malignant cells in vitro. In contrast, MNP didn’tshow any significant cytotoxic effect against normal cells. HeLa cells exhibited the highest susceptibility among the malignant cells. Mg0.6Fe2.4O4@OA show good cytotoxic activity against all examined malignant cells, significantly higher than other tested MNP. It can be seen that Mg0.6Fe2.4O4@PEG show a lower cytotoxic activity compared to all analyzed MNP. A direct method was used for labeling with radionuclide 90Y, which involves incubation of MNP with 90Y at a certain temperature and time. The labeling yield of the 90Y-coated MNP was determined by analyzing the radiochemical purity after labeling. 90YMg0.2Fe2.8O4@PEG were labeled in high yield (100%), while the yield for 90YMg0.2Fe2.8O4@CA was 83%. In vitro stability of 90Y-coated MNP at room temperature in physiological solution and human serum was monitored within 72 h from the moment of labeling by determining the radiochemical purity of ITLC-SG by radio chromatographic method. The stability of 90Y-Mg0.2Fe2.8O4@PEG was about 97%, whi

In the last decades, self-heating magnetic nanoparticles (MNPs) were engineered and investigated for magnetic hyperthermia (MH) and other applications such as catalysis and chemical synthesis. To be applied as nanoheaters for in vivo MH in cancer therapy, MNPs should have high heating efficiency expressed by Intrinsic Loss Power (ILP). One of the requirements for in vivo applications of MNPs is their non-toxicity. Hence, the most investigated MNPs for MH are based on iron oxides (magnetite and maghemite), which are non-toxic or slightly toxic. This work aimed to apply thepolyol-mediated protocol to engineer mixed Zn1-xMnxFe2O4 and analyze their heating abilities. To obtain a series of Zn1-xMnxFe2O4 samples with a specific nominal composition, the initial components, salts of Zn, Mn and Fe, were mixed in the appropriate stoichiometric ratio. The deviation from the target stoichiometry and the formation of samples with polyvalent ions and possibly vacancies were determined after ICP analysis. By analyzing TEM micrographs, we found that the change in the chemical composition does not affect the morphology. Multicore flower-like nanostructures with a size in the range of 47-63 nm were obtained. They consist of many cores (crystallites or nanoparticles) with a size of \textasciitilde10 nm. The samples show good colloidal stability, which is significant for their medical applications. Magnetization measurements in different DC fields showed that the samples are superparamagnetic at 300K and that the saturation magnetization values are in the range of \textasciitilde59-73 emu/g. The hyperthermic efficiency of the synthesized samples was tested in an external ac field of 252 kHz and a field strength of 15.9 kA/m. Significantly different values were obtained for the ILP parameter (in units nHm2/Kg): 5.77 (Zn0.098Mn0.447Fe2.455O4) ˃ 3.22 (Mn0.624Fe2.376O4) ˃ 2.04 (Zn0.182Mn0.344Fe2.474O4) ˃ 1.36 (Zn0.309Mn0.240Fe2.451O4) ˃ 1.01 (Zn0.394Mn0.138Fe2.468O4) ˃ 0.34 (Zn0.640Fe2.360

U ovom istraživanju, sintetisani su kompozitni nanomaterijali koji su korišćeni za modifikaciju elektrode od ugljenične paste. Materijali su sintetisani metodom koprecipitacije, a korišćene su soli nikla i bizmuta. Morfološke karakteristike materijala su ispitane skenirajućom i transmisionom elektronskom mikroskopijom i rendgenskom strukturnom analizom. Na osnovu ciklične voltametrije i elektrohemijske impedanse modifikovana elektroda pokazuje bolje elektrokatalitičke osobine od nemodifikovane elektrode.

In this study, a modified cobalt oxide (Co3O4) carbon paste electrode was prepared for the detection of Levofloxacin. Co3O4 nanoparticles were synthesized by the chemical coprecipitation method. The electrochemical properties of LEV at this electrode were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and differential pulse voltammetry (DPV). In addition, electrochemical impedance spectroscopy (EIS), inductively coupled plasma–optical emission spectrometry (ICP-OES), transmission and scanning electron microscopy (TEM and SEM) and X-ray diffraction (XRD) were used to characterize the synthesized materials.

(1) Background: An increasing use of pharmaceutics imposes a need for the permanent development of efficient strategies, including the tailoring of highly specific new materials for their removal from the environment. Photocatalytic degradation has been the subject of increasing interest of the researchers in the field. (2) Methods: This paper is focused on the investigation of the possibility to deposit a thin metal layer on a TiO2 surface and study its photocatalytic performance for the degradation of ciprofloxacin using a combination of theoretical and experimental methods. (3) Results: Based on the extensive DFT screening of 24 d-metals’ adhesion on TiO2, Cu was selected for further work, due to the satisfactory expected stability and good availability. The (Cu)TiO2 was successfully synthesized and characterized with XRD, SEM+EDS and UV-Vis spectrophotometry. The uniformly distributed copper on the TiO2 surface corresponds to the binding on high-affinity oxygen-rich sites, as proposed with DFT calculations. The photocatalytic degradation rate of ciprofloxacin was improved by about a factor of 1.5 compared to the bare non-modified TiO2. (4) Conclusions: The observed result was ascribed to the ability of adsorbed Cu to impede the agglomeration of TiO2 and increase the active catalytic area, and bandgap narrowing predicted with DFT calculations.

In this work, we investigated the morphological and electrochemical properties of gallium/bismuth mixed oxide. The bismuth concentration was varied from 0 to 100%. The correct ratio was determined with inductively coupled plasma-optical emission spectroscopy (ICP-OES), while surface characteristics were determined using scanning electron microscopy (SEM) and X-ray difraction (XRD) measurement. Electrochemical characteristics were studied using electrochemical impedance spectroscopy (EIS) in the Fe2+/3+ couple. The obtained materials were tested for adrenaline detection. After square wave voltammetry (SWV) optimization, the best electrode showed a wide linear working range from 7 to 100 µM at pH 6 of the Britton–Robinson bufer solution (BRBS) supporting electrolyte. The limit of detection (LOD) for the proposed method was calculated as 1.9 µM, with a limit of quantifcation (LOQ) of 5.8 µM. The excellent selectivity of the proposed method, with good repeatability and reproducibility, strongly suggests the possible application of the procedure for the determination of adrenaline in artifcially prepared real samples. The practical applicability with good recovery values indicates that the morphology of the materials is closely connected with other parameters, which further suggests that the developed approach can ofer a low-cost, rapid, selective, and sensitive method for adrenaline monitoring.

Nanomaterials are intensively researched both from the fundamental aspect due to new properties at the nanoscale, as well as the aspect of their application in many areas of technology. Magnetic nanoparticles (MNPs) are being tested for use in the diagnosis and therapy of diseases. A new field of medicine, Magnetic nanomedicine is primarily based on the application of MNPs as drug carriers, diagnostic agents in Magnetic Resonance Imaging (MRI) and heat generators in magnetic hyperthermia. Among nanoparticles, magnetic nanoplatforms based on iron oxides for cancer diagnosis and therapy (Cancer nanomedicine) are the most researched and clinically tested. This study presents the results of research into the physicochemical properties of iron oxide nanoparticles prepared by the polyol route, as well as their testing for potential applications as agents in magnetic hyperthermia (MH) and radionuclide carriers (vectors) for the diagnosis and therapy of malignant diseases. Multicore iron oxide structures synthesized by the "polyol" method represent clusters of single-core nanoparticles or crystallites. The dimensions of the single core particles are \textasciitilde13.5 nm, while the nanoflowers formed by clustering are \textasciitilde25 nm, depending on the applied synthesis parameters. For targeted medical applications, nanoflowers are coated with different ligands in order to increase colloidal stability and biocompatibility. The best results were by coating MNPs with polyacrylic acid (PAA). The multifunctionality of nanoflowers was investigated by measuring their hyperthermic efficiency for applications in magnetic hyperthermia and radiolabeling with diagnostic (99mTc) and therapeutic radionuclides (177Lu, 90Y). In addition to traditional methods of cancer therapy (surgery, radiotherapy, and chemotherapy), new ways of therapy such as MH are constantly being developed. MH is a therapy based on the property of MNPs that when placed in an alternating (AC) magnetic field, tr

Green synthesis is a more sustainable option using renewable biomass such as plants as reducing or stabilizing agents compared to toxic chemical compounds. These biological substances also behave as capping agents, which control the size and shape of the nanoparticles. In this work, ZnO nanoparticles (NPs) have been prepared via a simple, low cost and ecofriendly method using citrus fruit peel and extracts as biological reducing agents. Zinc nitrate and zinc acetate were used as a source of zinc ions.XRD analysis revealed the formation of a ZnO wurtzite phase without impurities. Synthesized ZnO NPs with an average electronic band gap ∼3 eV were obtained and found to have round-like, hexagonal-like or needle-like structures depending on precursor type. EDS analysis showed a homogeoneous distribution in Zn and O elements, attributed to single-phase ZnO constituents. Antibacterial and antioxidant activities of synthesized NPs were evaluated. Obtained results showed that ZnO synthesized from nitrate precursors are more effective in inhibiting growth of Salmonella and Staphylococcus Aureus. Antioxidant activity of ZnO NPs determined using CUPRAC and ABTS assays showed higher activity of ZnO obtained using nitrate precursors. The maximum scavenging activity of 90% was observed at the concentration of 10 mg/ml