Good Size Uniformity Research Articles

NLC Delivery of EGFP Plasmid to TM4 Cell Nuclei for Targeted Gene Therapy.

This study evaluated whether a nanostructured lipid carrier (NLC) delivery system could safely and accurately deliver nucleic acids to the cell nucleus using the enhanced green fluorescent protein (EGFP)-C1 plasmid model. The NLC was formulated using the emulsification method and equipped for cationic lipid-mediated transfection with 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), which interacts electrostatically with nucleic acid. The NLC attributes, including size, polydispersity index, and zeta potential, were assessed by dynamic light scattering (DLS). The morphological structure was analyzed using transmission electron microscopy. Entrapment efficiency was evaluated by a direct method. Cellular uptake mechanisms of pEGFP-C1-NLC and the ability of pEGFP-C1 to penetrate the nucleus of TM4 cells to express EGFP were observed using confocal microscopy. pEGFP-C1-NLC exhibited particle sizes in the range 56-88 nm with a particle charge range of -6.0 to+1.3 mV. The polydispersity index<0.5 showed good size uniformity, and entrapment efficiency of pEGFP-C1in the NLC was 92.06±2.295%. The NLC formulation was internalized predominantly via caveolae-mediated endocytosis, as indicated by EGFP expression following successful delivery of pEGFP by the NLC into the cells. NLC formulation could deliver genetic material to the nucleus and could be considered a gene therapy candidate for spermatogenesis.

Nanoscale Stolephorus sp. powder fabrication using high-energy milling for bioactive materials in dentistry.

The application of natural products in dentistry has been widely explored. Anchovy (Stolephorus in Latin) has been examined for its bioactive content (calcium, phosphorus and fluoride) as an agent for bone stimulation and tooth development, topical fluoridation and pulp capping. Ball milling has been used to prepare calcium oxide nanoparticles from snakehead fish bone. The aim of the study was to reduce the particle size of Stolephorus sp. powder to the nanoscale using high-energy ball milling for 8, 12 and 24 h, and to analyze the optimal milling time by comparing the powder characteristics. The Stolephorus sp. were oven-dried at 50°C for 6 h, after which the entire fish were crushed into powder. The fish powder was produced by blending the material for 5 min and passing it through a 200-mesh sieve. The remaining dried fish was blended again for 5 min until it passed through the sieve. The top-down approach to the particle size reduction was performed using high-energy milling at 3 distinct time points (8, 12 and 24 h). The characteristics of the powder were evaluated using a particle size analyzer, a Fourier-transform infrared spectrometer (FTIR) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The Stolephorus sp. powder contained 64.50% protein, 7,420 mg/kg sodium, 28,912 mg/kg calcium, and 1,924 mg/kg magnesium. The high-energy milling process resulted in a reduction of the particle size from the microscale to the nanoscale. The analysis of the average particle size and polydispersity index indicated that 24 h of milling showed the most optimal results. Furthermore, the functional groups exhibited no significant alteration at 3 milling times (p ≥ 0.05, FTIR analysis). The high-energy milling method has the potential to reduce the particle size of Stolephorus sp. powder to the nanoscale at the 8- and 24-h milling periods. The powder resulting from the 24-h milling process had a size of 789.3 ±170.7 nm, smooth size distribution, good size uniformity, a polydispersity index of 0.763, no significant change in organic and inorganic compound content, and a calcium/phosphorus ratio that was the closest to that of hydroxyapatite (HAp).

Evaluation of Single Dose and Fractionated Dose of I-131 Radiolabeled Nanoparticles for Triple-Negative Breast Cancer Treatment.

Combination chemotherapy is still the standard clinical care for triple-negative breast cancer (TNBC). However, sodium iodide symporter (NIS) uptake by TNBC has opened the potential of NIS as a molecular target for radioiodine theranostic treatments. Radiolabeled poly(lactic-co-glycolic) acid nanocarrier (NINP) was developed for NIS targeted delivery of I-131 to MDA-MB-231 cells to overcome I-131 low uptake in cancer cells and rapid clearance. The NINP diameter of 237 nm has good particle size uniformity and excellent particle stability. Radiochemical purity, radioactive stability, and radiolabeling yield of NINPs over 72 h were >95%. Cytotoxicity confirmed fractionated NINPs over 72 h to be more effective in cell death than single-dose NINP and both single and fractionated Na131I. Cellular uptake in a three-dimensional spheroid confirmed that NINP fractionated-dose achieved ~4.8-fold-higher mean fluorescent intensity than Na131I and ~2.7-fold greater reduction in cell viability compared to single-dose. The NINP fractionated-dose initiated greater cellular DNA damage to cells than single-dose NINP, resulting in inhibition of cell cycle progression, resulting in cell cycle progression being inhibited by cyclin-dependent kinases, which play a vital role in the control of MDA-MB-231 cell cycle. NINPs are biocompatible with blood, and were found to have no negative impact on red blood cells.

Multicolor tunable luminescence and energy transfer mechanism in Gd2O2S: Dy3+, Sm3+ phosphors

High quality single-phase multicolor emission phosphor is a prerequisite for efficient luminescence devices, but the system design and quantity preparation are still facing substantial challenges. Herein, Gd2O2S-based phosphors with high crystallinity, good dispersibility, and relatively good size uniformity were obtained by optimizing the type and components of flux based on the conventional solid-state method. By single-doping system study, the emission properties of matrix and activated ions are expounded, meanwhile the composition and co-excitation wavelength of co-doping system are designed. In the co-doping system, we mainly realized adjustable emission, interionic energy transfer, and application performance analysis. Firstly, multicolor emission in the range of yellow, orange and white was achieved through the modulation of dopant type and concentration as well as excitation wavelength. Secondly, the phenomena of spectral overlap (between Dy3+ and Sm3+), fluorescence intensity change (606 nm of Sm3+) and the monotonically decreasing fluorescence lifetime (Dy3+ at 578 nm) were evidence of energy transfer in the co-doping system. The theoretical fitting demonstrates that the energy transfer process of Dy3+→Sm3+ is primarily based on the quadrupole-quadrupole interaction mechanism. In addition, the cathodoluminescence spectra, temperature-dependent emission spectra, and magnetic properties tests have demonstrated the characteristics of multicolor adjustable emission (electron-beam excitation), excellent thermal stability, and good paramagnetic properties of the co-doping phosphors, further indicating that the Gd2O2S:Dy3+/Sm3+ system phosphors have potential as an excellent optical-magnetic bifunctional material in the fields of luminescence and bioimaging.

Fluorescence and Thermal Regulation Using Low-Supercooling Inorganic Microencapsulated Phase-Change Materials.

High supercooling and single functionalization are the main barriers to the large-scale application of microencapsulated phase-change materials (PCMs) in the construction industry. To address these issues, we propose a new inorganic microencapsulated PCM, PW@CaWO4, which was synthesized via the in situ polymerization method using inorganic CaWO4 as shell and phase-change paraffin wax (PW) as core. We investigated the effects of different emulsifiers and core-to-shell ratios on microcapsule properties and found that the PW@CaWO4 microcapsules have regular spherical topography and good uniformity in particle size. During the synthesis process, the CaWO4 shell provides convenient conditions for heterogeneous nucleation of PW and effectively reduces the supercooling degree. The minimum supercooling degree of the PW@CaWO4 microcapsules is only 1.00 ± 0.08 °C, which is 3.41 °C lower than that of PW. Moreover, the PW@CaWO4 microcapsules can absorb ultraviolet radiation and exhibit fluorescence, which originates from the peculiar WO42- structure in the CaWO4 shell, eliminating the need for doping other light-activating ions into the shell. The newly prepared microcapsules possess several advantages, including suitable particle size, low supercooling, good heat storage, high thermal conductivity, good short-wave ultraviolet absorption, peculiar fluorescence, excellent proof of leakage, and so on. The microcapsules can be applied to fluorescent architectural energy-saving coatings.

OPTIMIZATION OF ACYCLOVIR SUSPENSION: FORMULATING DEVELOPMENT USING NA-CMC AND QUALITY CONTROL OF FINISHED PRODUCTS

Objective: Acyclovir is widely used as a potent antiviral drug to treat viral infections of herpes and varicella-zoster families. Unfortunately, the drug has a very poor oral bioavailability character (15-30%). The purpose of this study was to develop a formulation of acyclovir suspension with a simple suspension method using Na-CMC (carboxymethylcellulose sodium), and to carry out quality control of the finished product.&#x0D; Methods: The formulation was developed by designing variations in Na-CMC concentration and quality control, including pH, viscosity, dispersibility, storage stability, microscopic measurement, sedimentation volume, and evaluation of acyclovir levels. Quality control is to evaluate the suspension in order to obtain good and stable physicochemical properties of the suspension.&#x0D; Results: Design variations of Na-CMC concentrations of 1.4%, 1.5%, and 1.6% resulted in a homogeneous suspension and easily dispersed perfectly. The three formulas did not have a significant difference in the value of viscosity, permeability, and sedimentation volume, which were not significant. All formulas have pseudoplastic flow properties, with good particle size uniformity in the range of 0–13 µm. The stability of pH during storage time was shown by the formula with 1.5% Na-CMC.&#x0D; Conclusion: The acyclovir suspension with 1.5% Na-CMC concentration was the best compared to the other formulas in terms of stability and physicochemical properties.

Size-controllable synthesis of covalently interconnected few-shelled Fe3O4@onion-like carbons for high-performance asymmetric supercapacitors

Fe3O4 is considered as an appealing anode material for constructing high-energy-density asymmetric supercapacitors owing to its high theoretical capacitance, large potential window, natural abundance and eco-friendliness. However, the dilemma of inadequate practical capacitance, low rate performance and unsatisfactory cycling stability of Fe3O4-based electrode materials significantly plagues their progress in supercapacitor applications. To well utilize the advantage of Fe3O4, herein, Fe3O4@onion-like carbons (OLCs) with covalently interconnected and few-shelled graphitic coatings were synthesized in a size-controllable manner from uniform-sized monodispersed nanoparticles of Fe3O4@oleic acid ligands. The ultrasmall-sized Fe3O4 nanoparticles with a good size uniformity enable a high electrochemical activity and a pseudocapacitive-dominated electrochemical behavior. Meanwhile, the efficient ion/electron transportations are facilitated by the structural advantages including covalently interconnected graphitic layers, conformal and seamless graphitic coating with ultrathin thickness, and hierarchical pores. As a result of the synergistic cooperation of these merits, the Fe3O4@OLCs hybrid structure exhibits a high specific capacitance of 686.1 F g−1 at 1 A g−1 and a high rate capability with 71.3% capacitance retention at 10 A g−1, superior to most of the reported Fe3O4-based electrode materials. An asymmetric supercapacitor device assembled based on Fe3O4@ OLCs shows a high energy density of up to 63.1 Wh kg−1, which is still maintained as high as 39.1 Wh kg−1 at a high power density of 1.49 kW kg−1. Moreover, a high cycling stability (more than 80% of initial capacitance remained after 10,000 cycles) is obtained. This study offers a novel strategy for preparing high-performance Fe3O4/carbon hybrid structures for asymmetric supercapacitor applications.

Effect of D-Limonene Nanoemulsion Edible Film on Banana (Musa sapientum Linn.) Post-Harvest Preservation.

D-limonene (4-isopropenyl-1-methylcyclohexene) is an important compound in several citrus essential oils (such as orange, lemon, tangerine, lime, and grapefruit). It has been used as a flavoring agent and as a food preservative agent, with generally recognized as safe (GRAS) status. D-limonene has been well-studied for its anti-inflammatory, antioxidant, anti-cancer, and antibacterial properties. The antibacterial activity of D-limonene against food-borne pathogens was investigated in this study by preparing a D-limonene nanoemulsion. The D-limonene solution and nanoemulsion have been prepared in six concentrations, 0.04%, 0.08%, 0.1%, 0.2%, 0.4%, and 0.8% (v/v), respectively, and the antibacterial activity was tested against four food-borne pathogens (Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica, and Escherichia coli). The results showed that the D-limonene nanoemulsion had good nanoscale and overall particle size uniformity, and its particle size was about 3~5 nm. It has been found that the D-limonene solution and nanoemulsion have a minimal inhibitory concentration of 0.336 mg/mL, and that they could inhibit the growth of microorganisms efficiently. The data indicate that the D-limonene nanoemulsion has more antibacterial ability against microorganisms than the D-limonene essential oil. After bananas are treated with 1.0% and 1.5% D-limonene nanoemulsion coatings, the water loss of the bananas during storage and the percentage of weight loss are reduced, which can inhibit the activity of pectinase. The application of a biocoating provides a good degree of antibacterial activity and air and moisture barrier properties, which help with extending the shelf life of bananas.

A strategy towards MF2:Yb3+, Er3+/SiO2 (M=Ba, Sr, Ca) yolk-shell nanofibers and yolk-shell nanobelts with up-conversion fluorescence

A simple and universal technique of the combination of uniaxial electrospinning with subsequent peculiar dual-crucible fluorination technology is innovatively designed and used to construct metallic fluorides yolk-shell nanofibers (YSNFs) and yolk-shell nanobelts (YSNBs) directly for the first time. As a case study, Yb3+/Er3+ co-doped alkaline earth metal fluoride (BaF2, SrF2 and CaF2) as core layer and SiO2 as shell layer are applied to construct the yolk-shell one-dimensional nanostructures. Under the optimum calcination temperature (600 °C) and time (5 h), the obtained MF2:Yb3+, Er3+/SiO2 (M=Ba, Sr, Ca) samples are of pure cubic phase, and display the yolk-shell nanofibers and yolk-shell nanobelts with good size uniformity and green up-converting fluorescence. By HF acid treatment of the samples, it is not only proved that the shell layer is SiO2, but also independent core-layer MF2:Yb3+, Er3+ (M=Ba, Sr, Ca) nanofibers and nanobelts with good size uniformity and excellent up-conversion luminescence are obtained. Especially, only fluorination process among the halogenation can form such exceptive YSNFs and YSNBs one-dimensional nanostructures, and the formation mechanisms of YSNFs and YSNBs are proposed and verified, and further the novel technique is established. The new technique possesses the merits of simple device and easy operation, large output, well-defined morphology and high preparative success rate of yolk-shell nanofiber and yolk-shell nanobelt, universality to metallic fluorides. The design philosophy and the construction technique for the exceptional yolk-shell one-dimensional nanostructures afford a facile approach for the fabrication of other functional metal fluorides yolk-shell one-dimensional nanostructures.

An injectable mPEG-PDLLA microsphere/PDLLA-PEG-PDLLA hydrogel composite for soft tissue augmentation

Injectable filling material is a simple and efficient method for soft tissues reconstruction and is extremely popular in not only plastic surgery but also cosmetic industry. However, there is a lack of soft tissue fillers with perfect performance on the market currently. Here, we constructed a new microsphere/hydrogel composite and evaluated its potential as a candidate for soft tissue augmentation. mPEG-PDLLA microspheres were prepared by utilizing a SPG membrane emulsifier which endowed microspheres with good sphericity and particle size uniformity. PDLLA-PEG-PDLLA hydrogel which shared the same component with the mPEG-PDLLA copolymer acted as a carrier and fixed the microspheres at the injected sites. The mPEG-PDLLA microsphere/PDLLA-PEG-PDLLA hydrogel composite was flowable in room temperature and transformed into gel after being heated to body temperature. This feature is convenient for subcutaneous filling. In vivo assessment on mice showed good safety profile of the composite. Moreover, the density of collagen fibers increased over 13 weeks. Overall, this biocompatible microsphere/hydrogel composite involves simple component and no extra crosslinking agents, and has the ability to stimulate collagen production, thus, may be a candidate for soft tissue augmentation.

Abstract 1389: Bismuth gadolinium nanoparticles enhance radiation therapy in hepatocellular carcinoma

Abstract Introduction: Primary cancers of the liver is the fourth most common cause of cancer-related deaths and the second most lethal tumor, with a 5-year survival rate of only 18%. Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Although HCC is a radiosensitive tumor, radiotherapy (RT) has had a limited role in therapy due to the sensitivity of normal liver parenchyma, thus minimizing radiation exposure is optimal. High atomic number nanoparticles (NP) like bismuth (Bi) and gadolinium (Gd) have been shown to be effective radiosensitizers. Exposure of NP to ionizing radiation leads to the emission of secondary electrons and photons that can damage cells by free radical components, resulting in radiation dose-enhancement. Here we synthesized a multifunctional theranostic NP containing both Bi and Gd (BiGdNP) that can act both as a radiosensitizer and as a bimodal contrast agent for T1 MRI and CT imaging. Materials and Methods: BiGdNP were synthesized using one-pot thermal decomposition of Bi(III) acetate and Gd(III) acetate. Morphology of the NP was characterized by transmission electron microscopy (TEM, JEOL) while Bi and Gd were quantified by inductively coupled plasma-mass spectrometry (ICP-MS, Agilent). Dose-dependent cytotoxicity of BiGdNP was assessed by alamarBlueTM assay. HepG2 cells with BiGdNP were irradiated at 0, 2, and 4 Gy using a 137Cs irradiator. Irradiated cells were incubated at 300 cells/well for 2 weeks. Surviving colonies (1 colony ≥50 cells) were fixed with 10% formalin and stained with 0.5% crystal violet for counting. Magnetic resonance imaging at 4.7 Tesla (Bruker) and micro-computed tomography imaging (GE Medical Systems) were performed on BiGdNP-injected C57BL/6 mice to evaluate liver uptake. Results: Synthesized BiGdNP have good size and shape uniformity with average size of 118 ± 16 nm. No significant difference in cell viability was observed with non-treated and BiGdNP-treated cells at a maximum concentration of 50 μg/mL (p&amp;gt;0.05, t test). This concentration was then used to treat the cells prior to gamma irradiation. In the absence of RT, no adverse effects were observed with BiGdNP-treated cells. For both the 2 and 4 Gy doses, surviving fractions in the BiGdNP-treated groups were decreased than non-treated groups (p&amp;lt;0.05, t test). In addition to radiosensitization, increasing the BiGdNP concentration resulted in increased radiopacity in μ- CT and shorter T1 relaxation time in MRI in vitro and contrast enhancement of the liver in both μ-CT and MRI following intravenous administration in vivo. Conclusion: BiGdNP in combination with RT is more efficient in reducing reproductive viability of HCC than RT alone. The added MRI/CT imaging modality can potentially aid in the visualization of tumor delineation to facilitate localized radiation treatment. Citation Format: Avinash Kakulavar, Raniv D. Rojo, Jossana A. Damasco, Marites P. Melancon, Joy V. Perez. Bismuth gadolinium nanoparticles enhance radiation therapy in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1389.

One-step synthesis of gold nanoparticles carried by boehmite

In this work, we proposed a simple method to synthesize gold nanoparticles carried by boehmite, which was made directly from Al/Au bilayer films by a one-step hydrothermal treatment. The boehmite carrier is porous with a special density-gradient structure. As a result, the embedded gold nanoparticles demonstrate good size uniformity, strong surface plasmon resonance, and good affinity for reacting solution. Such nanoparticles carried by boehmite exhibit the high potential of applications as efficient catalysts and sensitive bio-sensors.

Optimized Polyethylene Glycolylated Polymer-Lipid Hybrid Nanoparticles as a Potential Breast Cancer Treatment.

Purpose: The aim of this work is to optimize a polyethylene glycolated (PEGylated) polymer–lipid hybrid nanoparticulate system for the delivery of anastrozole (ANS) to enhance its biopharmaceutical attributes and overall efficacy. Methods: ANS loaded PEGylated polymer–lipid hybrid nanoparticles (PLNPs) were prepared by a direct emulsification solvent evaporation method. The physical incorporation of PEG was optimized using variable ratios. The produced particles were evaluated to discern their particle size and shape, zeta-potential, entrapment efficiency, and physical stability. The drug-release profiles were studied, and the kinetic model was analyzed. The anticancer activity of the ANS PLNPs on estrogen-positive breast cancer cell lines was determined using flow cytometry. Results: The prepared ANS-PLNPs showed particle sizes in the range of 193.6 ± 2.9 to 218.2 ± 1.9 nm, with good particle size uniformity (i.e., poly-dispersity index of around 0.1). Furthermore, they exhibited relatively low zeta-potential values ranging from −0.50 ± 0.52 to 6.01 ± 4.74. The transmission electron microscopy images showed spherical shape of ANS-PLNPs and the compliance with the sizes were revealed by light scattering. The differential scanning calorimetry DSC patterns of the ANS PLNPs revealed a disappearance of the characteristic sharp melting peak of pure ANS, supporting the incorporation of the drug into the polymeric matrices of the nanoparticles. Flow cytometry showed the apoptosis of MCF-7 cell lines in the presence of ANS-PLNPs. Conclusion: PEGylated polymeric nanoparticles presented a stable encapsulated system with which to incorporate an anticancer drug (ANS) with a high percentage of entrapment efficiency (around 80%), good size uniformity, and induction of apoptosis in MCF-7 cells.

Magnetic, Optical Properties, and Photocatalytic Activity of the ZnFe2O4 Nanoparticles for the Degradation of the RhB Dye in Wastewater: Effects of Metal Salt and Surface Morphology

Zinc ferrite nanoparticles are synthesized by a microwave assisted polyacrylamide gel route. The influence of different Zn salts includes zinc nitrate, zinc sulfate, zinc chloride, zinc acetate on the crystal structure, surface morphologies, optical properties, magnetic properties, and photocatalytic activity of the ZnFe2O4 nanoparticles were systematically studied. The ZnFe2O4 nanoparticles prepared using zinc nitrate have cubic spinel structure and exhibited good size uniformity and regularity. The absorption edge of ZnFe2O4 nanoparticles prepared using zinc nitrate as Zn salt shifted to a higher energy compared with that of ZnFe2O4 nanoparticles prepared by other Zn salts. The magnetic susceptibility indicates that the blocking temperature (TB) decreases from 94 to 35 K with Zn salt change from zinc nitrate to zinc sulfate due to the size effect. Interesting, zinc nitrate is used as Zn salt improves the photocatalytic activity for the degradation of rhodamine B (RhB) dye wastewater of ZnFe2O4 nanoparticles significantly due to introduced the surface species of OH– to the ZnFe2O4 nanopartciles. The recycling experiment indicates that the ZnFe2O4 nanopartciles have a high stability. The photocatalytic mechanism of ZnFe2O4 nanopartciles have been systematically studied on the basis of the photocatalytic experiment and electrochemical test.

Synthesis of Sub 3 nm-Sized Uniform Magnetite Nanoparticles Using Reverse Micelle Method for Biomedical Application.

We report a synthetic method for small and uniform Fe3O4 (magnetite) nanoparticles under mild conditions. Spherical sub-3 nm-sized magnetite nanoparticles were prepared via reverse micelles composed of oleylamine, F127, xylene, and water for the reaction of iron(III) stearate with hydrazine at a reaction temperature of 90 °C in air atmosphere. These synthesized magnetite nanoparticles exhibited good size uniformity. By controlling experimental conditions, we could easily control both size and size uniformity of these magnetite nanoparticles. We further investigated whether Fe3O4 could be used in biomedical applications. Cytotoxicity of Fe3O4 was evaluated with human adipose-derived stem cells (hADSCs). Our results showed that the number of hADSCs did not significantly decrease when these cells were treated with Fe3O4 nanoparticles at a concentration of up to 9 μg/mL. Apoptotic activity and cell proliferation of hADSCs treated with Fe3O4 nanoparticles were similar to those of hADSCs without any treatment. This novel method could be used for synthesizing uniform and biocompatible Fe3O4 nanoparticles with further biomedical applications.

Development of a Novel Tyrosinase Amperometric Biosensor Based on Tin Nanoparticles for the Detection of Bisphenol A (4.4-Isopropylidenediphenol) in Water

Highly crystalline poly-vinyl pyrrolidone (PVP) capped Sn nanocrystals with good size and shape uniformity was synthesized by a hydrothermal process. A highly sensitive amperometric biosensor for the detection of Bisphenol A (BPA) was developed by immobilizing Tyrosinase on to glassy carbon electrode (GCE) modified with Sn nanoparticles. The fabricated amperometric biosensor exhibited excellent electroactivity towards BPA oxidation catalysed by enzymatic reaction of tyrosinase together with good conductivity of Sn nanoparticles. The developed biosensor displayed linear range from 0.01 to 0.10 μmol L-1 and a detection limit (DL) of 1.8 nmol L-1 with a correlation coefficient of 0.989. Electrochemical impedance spectroscopy (EIS) obtained in buffer solution for Tyrosinase/SnNP/GCE had the lowest charge transfer resistance (Rct) value of 219 Ω, which indicated low charge transfer. There was an increase in Rct for Tyrosinase/GCE, SnNP/GCE and Bare GCE which was 316 Ω, 638 Ω and 598 Ω respectively. This indicated a strong resistance to charge transfer. It is reported for the first time the use of Sn nanoparticles modified on GCE and tyrosinase for detection of BPA.

STUDY OF CERIA STABILIZED ZIRCONIA MICROSPHERES MORPHOLOGY BY SMALL-ANGLE SCATTERING AND MICROSCOPY

STUDY OF CERIA STABILIZED ZIRCONIA MICROSPHERES MORPHOLOGY BY SMALL-ANGLE SCATTERING AND MICROSCOPY. Ceria stabilized zirconia microspheres of about 500 microns were prepared by external gelation. The morphology in nano and micro scale of the microsphere was evaluated. The nanostructure of CSZ microsphere after drying was studied by small angle neutron and x-ray scattering (SANS and SAXS). In this state, the existing of the mixture of ceria oxide and zirconia oxide was observed inside the polymer matrix. The roundness and surface properties of the CSZ microsphere were observed under the optical microscopy (OM) and scanning electron microscopy (SEM). The data showed their good size uniformity, smooth surface, but also the imperfect phase of the gelation.

Platelet CuSbS2 particles with a suitable conduction band position for solar cell applications

Single crystalline platelet chalcostibite (CuSbS2) particles with good shape and size uniformity were successfully prepared using a hot injection method. In this synthesis, sulfur powder in oleylamine (OLA) was employed as a sulfonating agent. The synthesized CuSbS2 had an orthorhombic structure with a plate-like morphology. Selected area electron diffraction (SAED) patterns confirmed their single crystal nature. Band gap calculation from diffuse reflectance data revealed that it had both direct and indirect band gaps of 1.52 eV and 1.46 eV, respectively. Moreover, valence band (VB) and conduction band (CB) positions were determined by cyclic voltammetry (CV) characterization. Optical and structural properties of CuSbS2 indicate its potential applicability for solar cell applications.

Solution synthesis of CuSbS2 nanocrystals: A new approach to control shape and size

Chalcostibite copper antimony sulfide (CuSbS2) micro- and nanoparticles with a different shape and size have been prepared by a new approach to hot injection route. In this method, sulfur in oleylamine (OLA) is employed as a sulfonating agent providing a simple route to control the shape and size of the particles, which enables the optimization of CuSbS2 for a variety of applications. The sulfur to metallic precursor ratio appears to be one of the most effective parameters along with the temperature and time for controlling the size and morphology of the particles. The growth mechanism study shows in addition to the CuSbS2 phase the presence of not previously observed intermediate phases (stibnite (Sb2S3) and famatinite (Cu3SbS4)) at the initial stage of the reaction. By increasing the ratio of sulfur to copper and antimony, wider and thinner CuSbS2 particles are obtained. The particles have nanoplate and nanosheet morphology with a good shape and size uniformity. Coalescence of very thin nanosheets occurs with increasing reaction time eventually leading to formation of thicker particles which can be called nanobricks. Band gap determinations demonstrate that the obtained CuSbS2 particles have both direct (1.51–1.57 eV) and indirect (1.44–1.51 eV) bandgaps. Transmission Electron Microscopy (TEM) studies revealed that the preferred growth directions are along the basis axes of the unit cell ([100] and [010]). Optical and structural properties of the obtained CuSbS2 particles are indicative for their great potential in different generations of solar cells and supercapacitor applications.

Transport Properties and Sensing Responses of Platinum Nanoparticles/Graphene Structure Fabricated by Thermal Annealing Process

The effects of the annealing temperatures and thicknesses on the shapes, sizes and arrangement of platinum (Pt) nanoparticles (NPs) on graphene and their sensing performance for hydrogen (H2) detection were investigated. It shows strong dependency of the annealing temperatures and thicknesses on the properties of NPs. It was found that the proposed technique is able to form the NPs with good size controllability and uniformity even for thick deposited layer, thus eliminating the requirement of very thin layer of below 5 nm for the direct NP synthesis by evaporation or sputtering. The transport properties of Pt NPs/graphene structure and its sensing performance on H2 at room temperature under various H2 concentration were evaluated. The results showed an acceptable sensing response, indicating an innovative approach to fabricate Pt NPs embedded graphene for gas sensing application.