Formation Of Spherical Particles Research Articles

In-situ fabrication of 3D/1D p-NiO/p-ZrO2 heterojunction composites with enhanced photo-degradation activity towards methyl orange and benzimidazole

In current work, p-p type NiO/ZrO2 composites (NZO-1 and NZO-2) were fabricated with the help of single step co-precipitation route. NiO to ZrO2 ratio was kept 9:1 and 8:2 for NZO-1 and NZO-2, respectively. As prepared composites were characterized by different physiochemical techniques. XRD data confirmed that cubic and monoclinic crystal phases of NiO and ZrO2 were present in both NZO-1 and NZO-2 composites. With the increase in concentration of ZrO2, crystallite size of NiO/ZrO2 was decreased from 16 nm to 14 nm. SEM analysis showed the formation of 3D quasi spherical particles of NiO and 1D nanoneedles of ZrO2. With FT-IR investigations different M − O bonds related to Ni–O and Zr–O were observed in NZO-1 and NZO-2. When used for photocatalytic activities, NZO-2 outperformed as compared to NZO-1 and pure constituents (NiO and ZrO2). In brief, NZO-2, NZO-1, NiO and ZrO2 removed 93, 80, 62 and 45% of Methyl orange (MO) dye in presence of natural sunlight within 120 min. Clearly, NZO-2 hold optimum concentrations of NiO and ZrO2 with a kinetic rate constant value of 0.019 min−1. Scavenging experiments disclosed electrons, superoxide radicals and holes were the main species involved in the photo-removal of MO. For benzimidazole, sufficient photo-degradation activity (57%) was observed in presence of NZO-2. Photo-catalytic investigations suggested that NZO-2 can be used as efficient photocatalyst for the treatment of multiple pollutants from contaminated water.

Optoelectronic properties of nanostructured Sb2Se3 films synthesized by electrodeposition method: Effect of Zn concentrations

In this research, the effect of different concentrations of Zn doping on antimony selenide (Sb2Se3) nanostructured films is investigated using electrodeposition method to study the properties of optoelectronics. XRD patterns confirmed the formation of polycrystalline orthorhombic Sb2Se3 films and FESEM images confirmed the formation of spherical particles at the nanoscale. Studying optical properties showed the band gap energy of less than 2.00 eV and investigating the electrical properties represented an increase in the density of electrical carriers in the films of Sb2Se3 with adding Zn concentrations. Photodetector parameters were calculated by photocurrent characterization and with alternating xenon light (on and off). It was found that sensitivity from 316.66 % to 4017.64 %, gain from 218.36 to 3924.30, responsivity from 0.0095 to 0.1708 mA/W, and specific detectivity from 1.02 × 10+9 to 1.54 × 10+9 Jones of the undoped sample reached its maximum possible value with increasing doping in the sample with maximum Zn concentration.

Low Cost Commercially Available Block Copolymer Derived Highly Porous Carbon for Advanced Supercapacitors

Increasing global warming and CO2 emission have created an urgent requirement of clean and green energy solutions which can resolve these issues. These energy solutions include fuel cells, batteries, and supercapacitors (SCs). Among them SCs are the devices of prime importance owing to their long cycle life (>106 charge discharge cycles) and wide applicability in variety of fields. Carbon based SC are commercialized and are being utilized worldwide, however their energy density (ED) is still limited to ~ 5 Wh.kg-1. Researchers have tried and reported various ways to improve its ED and overall performance. The surface area and porosity play a crucial role in deciding the overall performance of SCs. The higher specific surface area (SSA) and hierarchical pore structure with the good conductivity values are the desirable properties for the most suitable carbon electrode material. Block copolymers taking the advantage of structure directing property makes them suitable for tunning the surface area and porosity of product carbon material.Here, we have used the commercially available low-cost block copolymers including F127, and Brij-58 for the preparation of highly porous carbon materials. We have used low-cost glucose as the carbon precursor with KOH activation for improving the surface area values. The brief synthesis route includes the first step as the self-assembly of block copolymer template in the solvents like D.I. water and THF. Then the impregnation of carbon material is followed with the refluxing procedure followed by the hydrothermal treatment at 180 ºC for 5 h. Then the KOH activation and the further carbonization at various temperatures 700, 800 and 900 is performed. All the samples then washed with 5% HCl solution followed by repetitive D.I., methanol and ethanol washing. The final black colored powder is then utilized for various material and SC characterizations.The as synthesized material shows broad peaks around 25º in powder x-ray diffraction pattern. Moreover, the BET surface area measurement predicted the SSA in the range of 500-600 m2.g-1 for most of the samples. These SSA values are pretty much desirable for good capacitance storage. In addition to this the FESEM images shown in Figure 1 confirms the formation of spherical particles due to the structure direction of block copolymers. Along with this, the structural characterization including EDS and XPS further confirms the good carbon content in the developed material.The various developed materials were then tested for SC electrode in three electrode and two electrode measurements. The F127 directed carbon material has exhibited the maximum performance of ~ 250 F.g-1 at the scan rate of 5 mV.s-1, which is very good keeping in mind the low cost strategy for the synthesis of material. In two electrode packed device, the materials shows excellent specific energy of ~15 Wh.kg-1 with high specific power of 270 W.kg-1.Figure 1. a) low magnification FESEM image showing the formation of spherical shape particles directed by F127, b) high magnification image showing the single spherical particle directed by Brij 58, c) three electrode CV results at various scan rates for F127 derived spheres. Figure 1

Formation of spherical microporous silica particles from organosilane and quat molecules

The approach is developed to obtain submicron spherical particles of amorphous silica with interconnected micropores. The particles were synthesized via hydrolysis of organosilanes, i.e. tetraethoxysilane (TEOS) and (3-methacryloyloxy) propyltrimethoxysilane (MPTMOS) in a presence of quat surfactants. It was shown that the replacement of a part of TEOS with MPTMOS in the reaction mixture led to formation of particles containing only micropores instead of mesopores. At comparable amounts of MPTMOS and quat for both Cquat > CMC and Cquat < CMC the particle growth mechanism changed from aggregative to that of the layer-by-layer type. Presumably, various associates are formed in the reaction mixture from quat surfactant and MPTMOS molecules by the van der Waals and Coulomb interactions. The associates are built into the silica framework formed as a result of hydrolysis of organosilanes. After the organics are removed, a branched system of interconnected micropores 0.5 - 2 nm in size is formed within the particles at place of the associates. The synthesized microporous particles have a specific surface area of up to ~ 1000 m2 g−1 and pore volume of up to 0.5 cm3 g−1. The adsorption of transition-metal ions (Co2+, Ni2+) by the synthesized microporous particles was studied. It was shown that the adsorption capacity of microporous particles is twice that of particles with mesopores.

Structural, Third Order Nonlinear and magnetic properties of pristine and Ni-doped CuO nanoparticles: Diluted magnetic semiconductors

Ni-doped Copper Oxide nanostructures have been synthesized using the modified auto-combustion method. The structural, morphological, vibrational, linear, and nonlinear optical properties were examined. XRD pattern revealed that the samples exhibited a monoclinic structure having a space group C2/c. Origin of adsorbed oxygen and bivalent state of Cu and Ni were revealed from XPS analysis. HRTEM and FEG-SEM images with EDAX spectra confirmed the formation of spherical particles with smooth surfaces and also validated the purity of synthesized nanostructures. The magnetic measurements confirmed the nanoscale doping of Ni specifically from the superparamagnetic behaviors. The characteristic vibrational modes of CuO were identified from the vibrational analysis. The red-shifted Raman mode with broadening indicates the formation of disorders and size effects. The UV-Visible spectrum showed a decreasing trend in bandgap with an increment in nickel concentration, corresponding to the presence of intra-band defect/imperfection states. Emission peaks obtained from room temperature photoluminescent spectrum indicated the presence of defects in the nanostructures. Third-order nonlinear optical properties, measured via, the Z-scan method with the help of a continuous wave (CW) laser and an enhancement in the nonlinear optical parameters were observed on doping. Hence it confirmed that the prepared nanostructures can be used for various optoelectronic applications.

Microstructural and Surface Plasmon Resonance Properties of Green-Synthesized Ag Nanoparticles Using &lt;i&gt;Moringa oleifera&lt;/i&gt; Extract

Ag nanoparticles (NPs) have been successfully synthesized by the green synthesis method using Moringaoleifera (MO) extract with various incubation times (24 and 48 hours) as an active material for surface plasmon resonance (SPR) biosensor. Transmission electron microscopy analysis indicated the formation of spherical particles with an average crystal size of 29 nm. Selected area electron diffraction confirmed that Ag NPs is face-centered cubic (FCC) crystal structure. Fourier-transform infrared measurements show the band at 3330 cm-1, 2067 cm-1, 1634 cm-1 for an incubation time of 24 hours and 3328 cm-1, 2063 cm-1, 1633 cm-1 for an incubation time of 48 hours. The results prove the proteins and phenolics compound present in the MO extract responsible as reducing agents. The maximum absorption of the green-synthesized Ag NPs in the UV-Vis spectra shows the SPR band at 326 nm and 328 nm for an incubation time of 24 and 48 hours, respectively, and absorption intensity decrease with the increase of incubation time. The result shows the SPR angle shifted to the larger angle of incident light by using green-synthesized Ag NPs. However, the increased incubation time affects the angle shift to the lower angle of the SPR shift. The addition of the green-synthesized Ag NPs leads to enhance the sensitivity of the SPR biosensor.

Rare earth (RE: La and Ce) elements doped ZnWO4 nanoparticles for enhanced photocatalytic removal of methylene blue dye from aquatic environment

In the present study, the enhanced photocatalytic behaviour of La:ZnWO4 and Ce:ZnWO4 nanoparticles produced by a simple co-precipitation technique is reported. The X-ray diffraction study suggested that La and Ce ions are harmoniously incorporated into the Zn2+ sites or interstitial sites within the ZnWO4 lattice without altering the monoclinic wolframite phase. The field emission scanning electron microscopic study showed the formation of spherical particles and nanorod-like morphology for La:ZnWO4 and Ce:ZnWO4 samples. The shrinkage in optical band gap energy of La and Ce doped ZnWO4 nanoparticles was realized owing to the effect of dopant concentration induced microstructural defects. The broad blue-green emission peak perceived at 350–600 nm regions is ascribed to the electronic transition from O2p to W5d orbitals. The highest surface area of 283.272 m2/g was obtained for 2% La doped ZnWO4 sample. The elemental composition of samples was ascertained by x-ray photoelectron spectroscopic study. La:ZnWO4 and Ce:ZnWO4 nanophotocatalysts showed an excellent dye removal efficiency towards the degradation of methylene blue than the pure ZnWO4 catalyst. This may be due to the fact that the RE ions (La and Ce) endorse the separation of photo-induced electron-hole pairs in ZnWO4.

Green synthesis of ZnS nanoparticles using allium sativum l. extract and study of their structural, optical and electrical properties

This work presents a simple, low-cost and environmentally friendly approach for the synthesis of zinc sulfide nanoparticles (ZnS NPs) using Allium sativum L. plant extract. Formation of cubic ZnS NPs is confirmed from X-ray diffraction study. Transmission electron microscopy image confirms the formation of spherical particles of average size 6.5 nm. Direct band gap energy of the NPs is found to increase from 3.87 – 4.25 eV with increasing volume of the extract. Fourier transform infrared spectroscopy analysis confirms the presence of biomolecules in the extract which are involved in the formation of ZnS NPs. The possible growth mechanism of ZnS NPs within the biopolymer matrix has been discussed. The dielectric constant of ZnS NPs is higher than the bulk ZnS. A.C. conductivity increases with increasing frequency and changes practically linearly with applied frequency. The impedance study suggests that the ZnS samples could be used as nano-tuned devices in electronics. It is found that as crystallite size decreases, d.c conductivity rises.

Effect of Milling Parameters on Mechanical Properties and In Vitro Biocompatibility of Mg-Zn-Co Ternary Alloy

Magnesium (Mg) is a potential candidate for biomedical implants, but its susceptibility to suffer corrosion attack in human body fluid limits its practical use. Thus, alloying Mg with other metal elements is the most effective strategy to improve its mechanical properties and biocompatibility. Herein, we report a Mg-Zn-Co ternary alloy (85-10-5 wt %) synthesized by the mechanical alloying technique. Ball-milling parameters such as ball size and milling time were varied to obtain better alloy properties. After compaction and sintering, the obtained alloy samples were subjected to various characterizations, including grain, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD), microhardness and nanoindentation analyses. In vitro biocompatibility analysis of different alloys was also performed with MC3T3-E1 osteoblasts. Grain analysis confirmed the even dispersion of particles, while SEM analysis showed the formation of laminates, spherical and fine particles with an increase in time and varied ball size. XRD results further confirmed the formation of intermetallic compounds. The microhardness of samples was increased with the increase in milling time. The Young’s modulus of ternary alloys obtained from nanoindentation analysis was comparable to the modulus of human bone. Moreover, in vitro analysis with osteoblasts showed that the developed alloys were noncytotoxic and biocompatible.

The Effect of the Milling Vial Shape on the In-Situ Consolidation of a Nanocrystalline Al-Li-GNPs Nanocomposite Synthesized by Room Temperature Ball-Milling

Several studies investigating the ball-milling of ductile face-centered cubic metals have reported a so-called in-situ consolidation phenomenon where the milled powder is also consolidated during the milling process. Thus, instead of refined powders or agglomerated particles, the formation of spherical bulk particles of the milled material is reported using a combination of cryomilling and room temperature milling processes. In this study, we studied the effect of the milling vial shape on the in-situ consolidation of a graphene nanoplatelets (GNPs) reinforced aluminum-lithium (Al-Li) matrix nanocomposite for the first time. An in-situ consolidated nanometric Al-Li-GNPs nanocomposite with an average grain size of 48 nm and high hardness of 1.48 GPa was attained after only 8 h of room-temperature milling. The results presented suggest that dense nanostructured composites can be prepared by in-situ consolidation during a one-step milling process and subsequently investigated in order to analyze their mechanical behavior. This allows for the intrinsic mechanical behavior of the synthesized material to be examined without the interference of subsequent high-temperature consolidation processes, thus avoiding unwanted structural changes such as grain growth and second phase formations.

Surfactant Effect on the Physicochemical Characteristics of Solid Lipid Nanoparticles Based on Pillar[5]arenes.

Novel monosubstituted pillar[5]arenes containing both amide and carboxyl functional groups were synthesized. Solid lipid nanoparticles based on the synthesized macrocycles were obtained. Formation of spherical particles with an average hydrodynamic diameter of 250 nm was shown for pillar[5]arenes containing N-(amidoalkyl)amide fragments regardless of their concentration. It was established that pillar[5]arene containing N-alkylamide fragments can form spherical particles with two different sizes (88 and 223 nm) depending on its concentration. Mixed solid lipid nanoparticles based on monosubstituted pillar[5]arenes and surfactant (dodecyltrimethylammonium chloride) were obtained for the first time. The surfactant made it possible to level the effect of the macrocycle concentration. It was found that various types of aggregates are formed depending on the macrocycle/surfactant ratio. Changing the macrocycle/surfactant ratio allows to control the charge of the particles surface. This controlled property will lead to the creation of molecular-scale porous materials that selectively interact with various types of substrates, including biopolymers.

Spherical Particle Formation that Deteriorates Thixotropic Property and its Suppression Strategy for Diamide-Based Additives having Two-Hydrocarbons.

Spherical particle formation degrades the performance of castor-oil-derived thixotropic additives, which are widely used to a dripping preventing agent in automobile paints and household waste oil treatment agent. Double-chain-type diamide is a heat-resistant thixotropic additive that causes nanofibrosis; its entanglement and gelation embracing solvent molecules-originating from the abundant intermolecular hydrogen bonds-and easy forming/rupturing tendency result in spherical particle formation, which can be confirmed by the temperature and time of reserve heating. Diamides with two hydrocarbons that have undergone thermal treatment leading to spheroidization were found exhibit significantly different sublimation/pyrolysis temperature, melting temperature, and crystal orientation than non-treated diamides. By comparing with the change observed under more extreme heating conditions, it can be considered that the amide bond site would increase the bond length and suppress the degree of freedom of rotation just before bond cleavage. In this state, verification of the origin of spherical particle formation by using the Langmuir-Blodgett method revealed that anisotropic suppression of hydrogen bonding occurs. In addition, it was found that spheroidization can be suppressed by adding a growth aid when preheating is conducted under a certain condition.

Tuning polymorphs of precipitated calcium carbonate from discarded eggshells: effects of polyelectrolyte and salt concentration.

Biowaste eggshells are a valuable source of calcium carbonate suitable for various applications. In this study, spherical vaterite and calcite calcium carbonate polymorphs have been synthesised from discarded eggshells by the precipitation technique at ambient temperature. The influence of initial salt concentration with different polyelectrolytes such as ethylene glycol (EG), polyethylene glycol (PEG, 600 and 6000), and poly(sodium 4-styrenesulfonate) (PSS) at various w/v% concentrations on the polymorph crystal formation of precipitated calcium carbonate (PCC) particles was studied. The results indicated that PCC crystals with spherical, star-shaped and yarn shaped morphologies can be obtained based on the concentration of calcium ions and the presence of different polyelectrolyte solution. At low salt molar concentration, PEG-6000 and PSS polyelectrolytes were found to promote the formation of spherical vaterite calcium carbonate particles with particle mean diameters of 5.05 μm and 2.17 μm, respectively. Furthermore, silver nanoparticles were also loaded into the PCC particles in situ, and the surface area significantly increased from 2.2813 m2 g−1 in untreated ground eggshells to 30.4632 m2 g−1 in PCC particles in the presence of PSS and silver colloid solution. The EDS mapping revealed the average wt% of silver atoms loaded in PCC particles in the presence of PSS polyelectrolyte was lower (1.44 wt%) than in the presence of PEG-6000 (4.27 wt%) due to the silver encapsulation possibility during the core–shell formation, as confirmed by SEM images. The silver nanoparticle-loaded PCC particles in this study can be incorporated into the polymer matrix and employed for antimicrobial food packaging or wound dressing application.

Poly-3-Methyl Aniline-Assisted Spherical PbS Quantum Dots through the Ionic Adsorption Deposition Method as a Novel and Highly Efficient Photodetector in UV, Vis, and NIR Regions

This study describes the preparation and characterization of glass/poly-3-methyl aniline (P3MA)/PbS quantum dot (QD) optoelectronic photodetector to detect and sense the light in broad spectral regions of UV, Vis, and NIR. This work is carried out to solve the drawbacks of other studs that prepare detectors in just one or two optical regions. Previous studies have used high-priced techniques. The deposition of P3MA on the glass surface was carried out by in situ oxidation process. Then, this polymer film was used to assist the deposition of PbS-QD particles through the ionic adsorption deposition method. The latter was performed using four different concentrations of Pb(NO3)2 solution (0.01, 0.03, 0.05, and 0.07 M) to form four P3MA/PbS composites: I, II, III, and IV, respectively. The chemical structure, morphologies, and electrical and optical properties of these composites were determined using different analytical tools. The SEM confirmed the formation of spherical QD particles of PbS on the P3MA surface. The TEM analysis showed that the composite has an average size of 5 nm, with the interatomic distances of 0.4 nm. Furthermore, the optical band gap values were 1.53, 1.52, 1.50, and 1.51 eV, respectively. The optoelectronic device could detect and sense light from 390 to 636 nm under various optical wavelengths. The produced current density ([Formula: see text]) values decreased from 0.029 mA.cm-2 at 390 nm to 0.022 mA.cm-2 at 500 nm and then increased until 0.024 mA.cm-2 at 636 nm. The light sensing was determined through the photoresponsivity ([Formula: see text]) and detectivity ([Formula: see text]) parameters, in which the photodetector has [Formula: see text] and [Formula: see text] values of 0.29 mA.cm-2 and [Formula: see text] Jones, respectively. Finally, a simple mechanism was proposed to explain the light sensing through the prepared optoelectronic device. Soon, our team works on the industrial applications of this optoelectronic device in the industry field related to the great optoelectronic device technical properties and its low cost and easy preparation.

Enzymatic mediated modification of gum Arabic by curcumin oxidation products: Physicochemical and self-assembly study

Gum Arabic (GA) is a polysaccharide widely used in industry as an emulsifier and encapsulating agent. Nevertheless, its physicochemical properties can be largely improved. The objective of this study was then to modify its structure to improve its functionalities or to provide new ones. To do so, a heterogeneous catalysis process using a laccase and a phenolic compound, curcumin, in aqueous solution was performed. The laccase allowed the oxidation of curcumin, which was then able to be grafted onto the polymer. Therefore, this environmentally friendly process allowed the modification of GA with curcumin oxidation products (OXP) by creating ester bonds between GA and OXP. The molecular mass of GA was largely increased after functionalization. This product contained two fractions of approximately ∼1.165 × 108 g.mol−1 and ∼5.057 × 106 g.mol−1. All these modifications impacted greatly the polymer properties such as its thermal behaviour, with a significant decrease of its glass transition, its hydrophilicity and its hygroscopicity. They also brought antioxidant properties to the modified GA. Moreover, the modification led interestingly to the spontaneous formation of spherical monodisperse micrometric particles in water.

Spherical red-emitting X1-Y2SiO5:Eu and α-Y2Si2O7:Eu phosphors with high color purity: The evolution of morphology, phase and photoluminescence upon annealing

Spherical silicate phosphor has widespread application in display or lighting industry. By using spherical silica particles as the core, we successfully prepared shell-thickness-controllable core/shell spherical particles, which can then be controllably converted to spherical X1-Y2SiO5:Eu (YSO:Eu) and α-Y2Si2O7:Eu (YPS:Eu) particles upon annealing. Even after 1000–1200 °C annealing, both X1-YSO:Eu and α-YPS:Eu particles still had the spherical shape and narrow size distribution. The shell thickness and annealing temperature synergistically controlled the phase evolution upon annealing. Thinner shell of around 30 nm, having extremely high chemical reaction activity, promoted the formation of spherical X1-YSO:Eu particles at 1000 °C and α-YPS:Eu particles at 1100 °C. Shell of around 85 nm produced spherical X1-YSO:Eu particles at 1100 °C and α-YPS:Eu particles at 1200 °C. Thicker shell also promoted the formation of spherical particles, but these particles usually had the mixed silicate phases. The phase-dependent photoluminescence properties were investigated in detail. Both spherical X1-YSO:Eu and α-YPS:Eu phosphors emitted reddish-orange color, with nearly 100% color purity and dominant wavelength of around 601 nm, which would absorb great attention for the application in display or lighting devices.

Fabrication of titanium doped BiVO4 as a novel visible light driven photocatalyst for degradation of residual tetracycline pollutant

In this study, titanium (Ti) was used as an active dopant to incorporate into BiVO4 lattice using the hydrothermal method. The synthesized BiVO4 and Ti–BiVO4 with 1, 5 and 10 wt% of Ti dopants have been applied for photocatalytic decomposition of Tetracycline under visible light irradiation. The characterized results showed that this synthesized BiVO4 and Ti–BiVO4 materials existed in a form of spherical particles. The particle sizes of the Ti–BiVO4 were much bigger than that of the BiVO4. However, Ti dopants effectively enhanced visible light absorption, decreased band gap energy as well as prevented electron-hole recombination of the BiVO4 leading to increase in photocatalytic activities of the doped materials. The obtained results from photocatalytic experiments indicated that the 5Ti–BiVO4, whose weight ratio of Ti was 5%, was the best material for TC degradation (78.49%). Recycling tests were consecutively carried out in 4 runs to demonstrate the stability of the BiVO4 photocatalyst with 5 wt% of Ti dopant.

Optically active porous hybrid particles constructed by alkynylated cellulose nanocrystals, helical substituted polyacetylene, and inorganic silica for enantio-differentiating towards naproxen.

This article reports on a novel type of ternary chiral porous hybrid particles (TCPHPs) constructed by alkynylated cellulose nanocrystals (A-CNCs), helical substituted polyacetylene, and inorganic silica. The resulting TCPHPs combine the respective advantages of the three components. A-CNCs serve as stabilizer, co-monomer, and chiral source simultaneously and transfer their chirality to the resulting helical substituted polyacetylenes in the course of copolymerization with achiral acetylenic monomer following "sergeants and soldiers rule". Helical substituted polyacetylenes form chiral helical structures and thus endow TCPHPs with the anticipated optical activity. Inorganic silica constitutes the rigid framework and is covalently bonded with the organic components through hydrolysis of Si-O-Et groups. Phase separation between the organic and inorganic components renders TCPHPs with abundant pores. Scanning electron microscope (SEM) images confirm the formation of spherical particles with porous structures. Circular dichroism spectra demonstrate the optical activity of the chiral hybrid particles. The as-prepared TCPHPs exhibit capacity for enantio-differentiating performance towards chiral naproxen.

Nipecotic-Acid-Tethered, Naphthalene-Diimide-Based, Orange-Emitting Organic Nanoparticles as Targeted Delivery Vehicle and Diagnostic Probe toward GABAA-Receptor-Enriched Cancer Cells.

This article demonstrates target-specific cellular imaging of GABA (γ-aminobutyric acid) receptor (GABAAR)-enriched cells (SH-SY5Y and A549) with therapeutic efficacy by naphthalene diimide (NDI)-derived fluorescent organic nanoparticles (FONPs). Self-assembly-driven formation of spherical organic particles by nipecotic-acid-tethered l-aspartic acid appended NDI derivative (NDI-nip) took place in DMSO-water through J-type aggregation. NDI-nip having a naphthyl residue and a nipecotic acid unit at both terminals exhibited aggregation-induced emission (AIE) at and above 60% water content in DMSO because of excimer formation at λem = 579 nm. The orange-emitting NDI-nip FONPs (1:99 v/v DMSO-water) having excellent cell viability and high photostability were used for selective bioimaging and killing of GABAAR-overexpressed cancer cells through target-specific delivery of the anticancer drug curcumin. The fluorescence intensity of NDI-nip FONPs were quenched in GABAAR-enriched neuroblastoma cells (SH-SY5Y) and cancerous cells (A549). Notably, in the presence of GABA, the NDI-nip FONPs exhibited their native fluorescence within the same cell lines. Importantly, no such quenching and regaining of NDI-nip FONP emission in the presence of GABA was noted in the case of the noncancerous cell NIH3T3. The killing efficiency of curcumin-loaded NDI-nip FONPs ([curcumin] = 100 μM and [NDI-nip FONPs] = 50 μM) was significantly higher in the cases of SH-SY5Y (88 ± 3%) and A549 (72 ± 2%) than in NIH3T3 (37 ± 2). The presence of a nipecotic acid moiety facilitated the selective cellular internalization of NDI-nip FONPs into GABAAR-overexpressing cells. Hence, these orange-emitting NDI-nip FONPs may be exploited as a targeted diagnostic probe as well as a drug delivery vehicle for GABAAR-enriched cancer cells.

Synthesis of Anatase/Brookite Mixed Phase TiO2 Nanostructures and its Photocatalytic Performance Study

AbstractThe TiO2 nanostructures were prepared using hydrothermal reaction technique at different reaction temperatures viz., 120 °C, 160 °C, and 200 °C for 24 h. The synthesized TiO2 nanostructures was characterised by various spectroscopic techniques. XRD indicate the formation of highly crystalline nano size particles of anatase phase of TiO2 along with minor percentage of brookite phase. Diffuse reflectance UV‐Visible spectroscopy depicts the band gap around 3.2 eV. The FE‐SEM shows formation of spherical particles having size in the range of 5 to 10 nm, however the small particles tend to agglomerate leading to the formation of submicron size clusters. TEM analysis confirms the formation of nanostructured TiO2 having size in the range of 5 to 10 nm with distorted spherical shaped morphology. The photocatalytic performance of the synthesized TiO2 was investigated by observing the degradation of aqueous methylene blue (MB) dye and H2 generation via water splitting under 400 W mercury vapour lamp respectively. Among the prepared samples, the TiO2 prepared at 160 °C, showed highest MB degradation (97 %) within 1 h of irradiation time. The photocatalytic H2 generation via water splitting was also investigated and found to be highest for TiO2 prepared at 160 °C, the observed rate of H2 generation was 3848 μmol/0.1 g in 4 h is almost twelve fold higher than the pure anatase phase.