Probe Ultrasonication Research Articles

Alginic Acid-Aided Dispersion of Carbon Nanotubes, Graphene, and Boron Nitride Nanomaterials for Microbial Toxicity Testing.

Robust evaluation of potential environmental and health risks of carbonaceous and boron nitride nanomaterials (NMs) is imperative. However, significant agglomeration of pristine carbonaceous and boron nitride NMs due to strong van der Waals forces renders them not suitable for direct toxicity testing in aqueous media. Here, the natural polysaccharide alginic acid (AA) was used as a nontoxic, environmentally relevant dispersant with defined composition to disperse seven types of carbonaceous and boron nitride NMs, including multiwall carbon nanotubes, graphene, boron nitride nanotubes, and hexagonal boron nitride flakes, with various physicochemical characteristics. AA’s biocompatibility was confirmed by examining AA effects on viability and growth of two model microorganisms (the protozoan Tetrahymena thermophila and the bacterium Pseudomonas aeruginosa). Using 400 mg·L−1 AA, comparably stable NM (200 mg·L−1) stock dispersions were obtained by 30-min probe ultrasonication. AA non-covalently interacted with NM surfaces and improved the dispersibility of NMs in water. The dispersion stability varied with NM morphology and size rather than chemistry. The optimized dispersion protocol established here can facilitate preparing homogeneous NM dispersions for reliable exposures during microbial toxicity testing, contributing to improved reproducibility of toxicity results.

Effect of Ultrasound Probe Homogenization to Improve Sucrose Recovery from Sugar Factory Products

Event Abstract Back to Event Effect of Ultrasound Probe Homogenization to Improve Sucrose Recovery from Sugar Factory Products Marsha R. Cole1* and William B. Morris1 1 Louisiana Tech University, United States Abstract: Maximizing sugar recovery from bagasse and final molasses is economically important to sugar mills. On average, approximately 20-40 lb sucrose per ton of crushed cane is lost to the molasses and bagasse each year. Evaluating that sucrose loss in terms of the amount of cane crushed in Louisiana in 2016, approximately 128,000–250,000 tons of sucrose was left unrecovered and $76-152 millions of profitable dollars were untapped. This is largely due to increases in massecuite viscosity (molasses + sucrose crystals) that limits molasses exhaustion and sucrose recovery. This presents a critical need for technologies to improve sucrose recoveries from final molasses for the sugar industry to be more profitable. This research investigated whether the use of probe ultrasonication technology can improve the viscosity of final C molasses obtained from two Louisiana sugar mills (LSM 1 and LSM 2). As expected, sonication (3 – 10 min, 60% amplitude) improved the viscosity of both LSM 1 and LSM 2 samples as temperature increased from 40°C to 60°C. Upon comparing the effects of sonication to the nontreated control, the viscosity for LSM 1 improved by 6.3, 21.2, 14.9, and 11.0% at 25, 40 (factory storage temperature), 50, and 60°C (factory flowing temperature), respectively. For LSM 2, mean improvements in viscosity between the nontreated control and sonicated samples were 32.6, 23.1, 29.0, and 39.7% at 25, 40, 50, and 60°C, respectively. Results indicate that sonication shows potential to improve molasses handling at temperatures at or below 40°C by improving flowability and viscosity. Complementary ATR-IR confirmed that viscosity improvements were attributable to reductions in hydrogen bonding between polar impurities. More studies are on-going to determine whether sonication affected the hydrogen bonding between the processing or natural impurities in the molasses and if their molecular weight distributions were reduced. Acknowledgements American Sugar Cane League Alma Sugar Plantation Enterprise Plantation Keywords: Sucrose recovery, Molasses, Sonication, Sugar manufacture, Viscosity, Sugar boiling, Sugar yield Conference: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference , Orlando, Florida, United States, 17 Sep - 20 Sep, 2018. Presentation Type: Oral Presentation Topic: Analytical Chemsitry Citation: Cole MR and Morris WB (2019). Effect of Ultrasound Probe Homogenization to Improve Sucrose Recovery from Sugar Factory Products. Front. Chem. Conference Abstract: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference . doi: 10.3389/conf.fchem.2018.01.00032 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 Oct 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. Marsha R Cole, Louisiana Tech University, Ruston, United States, cole@latech.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Marsha R Cole William B Morris Google Marsha R Cole William B Morris Google Scholar Marsha R Cole William B Morris PubMed Marsha R Cole William B Morris Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Skin targeting of curcumin solid lipid nanoparticles-engrossed topical gel for the treatment of pigmentation and irritant contact dermatitis

Irritant contact dermatitis (ICD) and hyperpigmentation are the problems associated with skin. Topical curcumin (CUR) although effective in hyperpigmentation and ICD, is a challenging molecule due to low-solubility. Encapsulation of CUR into solid lipid nanoparticles (SLNs) makes it amenable to topical dosing as their small size promotes its penetration into the skin. CUR-SLNs were prepared using Precirol ATO5 and Tween-80 by probe ultrasonication method. Further, CUR-SLNs were incorporated into Carbopol gel and investigated for ex-vivo skin permeation, skin deposition and skin irritation studies. The potential of CUR-SLN gel was checked against hyperpigmentation through the inhibition of tyrosinase enzyme. It was further evaluated for possible effects on ICD using BALB/c mice. The optimized CUR-SLN showed the particle size of 51 nm and 93% EE. Ex vivo permeation of CUR-SLN gel exhibited controlled drug release up to 24 h, similarly in vitro drug deposition studies showed potential for skin targeting. In vitro tyrosinase inhibition assay indicates that the formulated gel has potential in skin depigmentation. The gel also confirmed proficient suppression of ear swelling and reduction in skin water content in the BALB/c mouse. Thus, the CUR-SLN gel would be a safe and effective alternative to conventional vehicles for treatment of ICD and pigmentation.

On the Development of Hierarchical Nanostructures of Graphene-Zinc antimonate as Inexpensive Electrode Materials for Supercapacitors

Supercapacitor performance of hybrid nanostructure (graphene-zinc antimonate) was explored, in which the 2D graphene and 1D zinc antimonate nanostructures were prepared by probe ultrasonication and precipitation methods respectively and the nanocomposites were fabricated in two different weight ratios by simple homogenous magnetic stirring method. Crystal structure, vibrational modes and synergistic interactions were studied through XRD, SAED and Raman spectral investigations. Morphology and interatomic features were viewed through FESEM and HRTEM investigations. Optical absorption, band gap and emission properties were analyzed through UV-DRS and PL studies and the fabricated nanostructure can anchor as charge trappers and charge recombination inhibitors. XPS spectral studies were confirmed the chemical composition of respective elements as well as chemical interactions between two different quantum nanostructures. The electrochemical tests were carried out using CV, GCD and EIS measurements. The fabricated nanostructures exhibit EDLC behavior with a maximum specific capacitance of 228.57F/g and 1470.25F/g at a current density of 1A/g in 1M H2SO4 electrolyte that was obtained due to the synergistic interaction between graphene and ZSO nanorods and non-aggregation effect. Cycling tests were measured at a current density of 5A/g for 2000 charge/discharge cycles and the prepared composite nanostructure exhibits a better electrochemical stability which was supported by AC impedance studies. These diversified properties make the hybrid nanostructures as an efficient electrode material in supercapacitors.

A study of the main factors affecting the performance of self-sensing concrete

Concrete sensors, which are manufactured by mixing conductive fibres (such as carbon nanotubes (CNTs)) with concrete, are one of the most significant and economical types of sensor. Two main factors affecting the performance of concrete sensors are the amount of CNTs and the quality of their dispersion in the mixture with regard to the combined effects of the surfactant composition and CNTs dispersed with different levels of energy. The goal of this research was to evaluate the effects of the main parameters affecting concrete sensor performance using various criteria (sensitivity of the sensor, standard deviation of the prediction error, repeatability, cross-correlation and hysteresis) in both static and dynamic loading regimes. Dynamic criteria such as sensitivity, internal repeatability, cross-correlation and hysteresis showed that the energy levels for the dispersion of CNTs have a greater effect on improving sensor performance than the amount of CNTs. On the contrary, the repeatability indicated that the amount of CNTs has a greater effect on sensor performance than the dispersion quality (energy level) of the CNTs. On the whole, the sensor produced with 0·15 wt% (by weight of cement) CNTs, superplasticiser and sodium dodecyl sulfate as a surfactant using the maximum energy level (ultrasonic bath for 2 h and 90 min of probe's ultrasonication) offered the best performance both in the static and dynamic load regimes.

Improved yeast delivery of fluconazole with a nanostructured lipid carrier system.

Despite the growing trends in the number of patients at risk for invasive fungal infections, management with current antifungal agents results in complications due to changes in the epidemiology and drug susceptibility of invasive fungal infections. In the present research fluconazole-loaded nanostructured lipid carriers were prepared using probe ultrasonication techniques and investigated the efficacy of the optimal formulation on a large number of Candida species. The morphology of the obtained nanostructured lipid carriers was characterized by transmission-electron microscopy. The minimum inhibitory concentrations (MIC) for the new formulations against strains of Candida were investigated using the Clinical and Laboratory Standards Institute document M27-A3 and M27-S4 as a guideline. The fluconazole-loaded nanostructured lipid carriers presented a spherical shape with a mean diameter, zeta potential and entrapment efficiency of 126.4±15.2nm, -35.1±3.0mV, and 93.6±3.5%, respectively. The drug release from fluconazole-loaded nanostructured lipid carriers exhibited burst-release behavior at the initial stage followed by sustained release over 24h. Using a new formulation of fluconazole led to a significant decrease in MICs for all Candida groups (P<0.05). Furthermore, C. albicans isolates showed more susceptibility to fluconazole-loaded nanostructured lipid carriers than C. glabrata and C. parapsilosis (P<0.05). The MIC50 drug concentration was obtained as 0.0625, 0.031 and 0.25μg/ml for fluconazole-resistant strains of C. albicans, C. glabrata, and C. parapsilosis, respectively. In conclusion, a novel delivery system which can be used as part of a strategy to improve the antifungal activity of fluconazole against various Candida strains with different susceptibilities to conventional formulations of fluconazole was evaluated.

Efficacy of nano- and microemulsion-based topical gels in delivery of ibuprofen: an in vivo study

Aim: Nanoemulsion has shown many advantages in drug delivery systems. In this study, for the first time, analgesic and anti-inflammatory properties of a nanomelusion of almond oil with and without ibuprofen was compared with corresponding microemulsion and commercial topical gel of the drug using formalin and carrageenan tests, respectively.Method: Almond oil (oil phase) was mixed with Tween 80 and Span 80 (surfactants), and ethanol (co-surfactant) and them distilled water (aqueous phase) was then added to the mixture at once. Prepared nanoemulsions were pre-emulsified into a 100 ml beaker using magnet/stirrer (1000 rpm). Then, using a probe ultrasonicator (Hielscher UP400s, Hielscher, Ringwood, NJ) the nanoemulsions were formed.Results: The optimised nanoemulsion formulation containing 2.5% ibuprofen, showed improved analgesic and anti-inflammatory effects compared with commercial product and corresponding microemulsion product containing 5% ibuprofen (i.e. twice the content of ibuprofen in the nanoemulsion) in vivo. The nanoemulsion preparation showed superior analgesic activities during chronic phase. Also, it decreased the inflammation from the first hour, while the microemulsion and the commercial product started to show their anti-inflammatory effects after 2 and 3 h, respectively.Conclusion: Our finding suggests that the size of the emulsion particles must be considered as an important factor in topical drug delivery systems.

Graphite Nanoplatelet Modified Epoxy Resin for Carbon Fibre Reinforced Plastics with Enhanced Properties

A simple approach to deliver graphene or graphite nanoplatelets (GNPs) into carbon fibre reinforced plastic (CFRPs) to enhance the multifunctional properties of carbon/epoxy laminates was demonstrated. GNPs improved the typically low interlaminar mechanical, thermal, and electrical properties of CFRPs after direct vacuum infusion of GNP doped resin obtained via in situ exfoliation by three-roll milling (TRM). Compared to high shear mixing or probe ultrasonication, TRM produces higher shear rates and stresses to exfoliate and finely disperse GNP particles within an epoxy matrix. This environmentally friendly and industrial scalable process does not require the use of solvents, additives, or chemical treatments. The flexural modulus and interlaminar shear strength (ILSS) of CFRPs was increased by 15% and by 18%, respectively, with the addition of 5 wt.% in situ exfoliated GNP in the doped epoxy resin. Out-of-plane electrical and thermal conductivity, at the same filler content, were, respectively, improved by nearly two orders of magnitude and 50%.

Skin targeting of resveratrol utilizing solid lipid nanoparticle-engrossed gel for chemically induced irritant contact dermatitis.

Irritant contact dermatitis (ICD) is a chronic and relapsing skin disease with severe eczematous lesions. Despite its growing prevalence, therapeutic treatments remain limited. Long-term topical corticosteroid treatment can induce skin atrophy, hypopigmentation, and increase in transepidermal water loss. An innovative dermal treatment is essential to reduce the side effects of corticosteroids. Topical resveratrol (RES), although effective for ICD, is a challenging molecule due to low solubility and poor bioavailability. The objective of this work was to build RES-loaded solid lipid nanoparticles (RES-SLNs) with skin targeting. For this purpose, RES-SLNs were prepared using the probe ultrasonication method utilizing Precirol ATO 5 and Tween 20. The RES-SLNs were evaluated for particle size, entrapment efficiency (EE), and transmission electron microscopy (TEM) studies. Further, RES-SLNs were incorporated into Carbopol gel and investigated for ex vivo skin permeation, deposition study on human cadaver skin, and finally skin irritation study on New Zealand White rabbits. It was further assessed for possible beneficial effects on ICD using BALB/c mice. RES-SLN showed mean size below 100nm and 68-89% EE. TEM studies confirmed spherical particles in the nanometer range. An ex vivo study of RES-SLN-loaded gel exhibited controlled drug release up to 24h; similarly, in vitro drug deposition studies showed potential of skin targeting with no skin irritation. RES-SLN gel confirmed competent suppression of ear swelling and reduction in skin water content in the BALB/c mouse model of ICD when compared to marketed gel. Thus, the formulated RES-SLN gel would be a safe and effective alternative to conventional vehicles for treatment of ICD.

Optimisation of asymmetric flow field-flow fractionation for the characterisation of nanoparticles in coated polydisperse TiO2 with applications in food and feed

ABSTRACTTitanium dioxide (TiO2) has various applications in consumer products and is also used as an additive in food and feeding stuffs. For the characterisation of this product, including the determination of nanoparticles, there is a strong need for the availability of corresponding methods of analysis. This paper presents an optimisation process for the characterisation of polydisperse-coated TiO2 nanoparticles. As a first step, probe ultrasonication was optimised using a central composite design in which the amplitude and time were the selected variables to disperse, i.e., to break up agglomerates and/or aggregates of the material. The results showed that high amplitudes (60%) favoured a better dispersion and time was fixed in mid-values (5 min). In a next step, key factors of asymmetric flow field-flow fraction (AF4), namely cross-flow (CF), detector flow (DF), exponential decay of the cross-flow (CFexp) and focus time (Ft), were studied through experimental design. Firstly, a full-factorial design was employed to establish the statistically significant factors (p < 0.05). Then, the information obtained from the full-factorial design was utilised by applying a central composite design to obtain the following optimum conditions of the system: CF, 1.6 ml min–1; DF, 0.4 ml min–1; Ft, 5 min; and CFexp, 0.6. Once the optimum conditions were obtained, the stability of the dispersed sample was measured for 24 h by analysing 10 replicates with AF4 in order to assess the performance of the optimised dispersion protocol. Finally, the recovery of the optimised method, particle shape and particle size distribution were estimated.

The studies of PLGA nanoparticles loading atorvastatin calcium for oral administration in vitro and in vivo

A biodegradable poly(lactic-co-glycolic acid) loading atorvastatin calcium (AC) nanoparticles (AC-PLGA-NPs) were prepared by probe ultrasonication and evaporation method aiming at improving the oral bioavailability of AC. The effects of experimental parameters, including stabilizer species, stabilizer concentration and pH of aqueous phase, on particle size were also evaluated. The resultant nanoparticles were in spherical shape with an average diameter of 174.7 nm and a narrow particle size distribution. And the drug loading and encapsulation efficiency were about 8% and 71%, respectively. The particle size and polydispersion were almost unchanged in 10 days. The release curves of AC-PLGA-NPs in vitro displaying sustained release characteristics indicated that its release mechanisms were matrix erosion and diffusion. The pharmacokinetic study in vivo revealed that the Cmax and AUC0-∞ of AC-PLGA-NPs in rats were nearly 3.7-fold and 4.7-fold higher than that of pure atorvastatin calcium suspension. Our results demonstrated that the delivery of AC-PLGA-NPs could be a promising approach for the oral delivery of AC for enhanced bioavailability.

Development and assessment of ceria–propylene glycol nanofluid as an alternative to propylene glycol for cooling applications

Spherical, crystalline ceria nanoparticles of 18–25nm were synthesized from cerium nitrate precursor. The dispersion of as-synthesized ceria nanoparticles in propylene glycol was achieved through extended probe ultrasonication for 14h, leading to ceria–propylene glycol nanofluids. The influence of nanoparticle concentration (0–1vol.%) and temperature on viscosity and thermal conductivity of ceria–propylene glycol nanofluids were investigated. Our data indicate that the higher thermal conductivity enhancement at elevated temperatures (18.8% at 80°C for 1vol.% nanofluid) can be attributed to the particle clustering and Brownian-motion induced microconvection. Ceria nanoparticles interact with propylene glycol leading to disturbance in hydrogen bonding network prevalent in propylene glycol. This resulted in lower viscosity of 0.5vol.% and 1vol.% ceria–propylene glycol nanofluids than propylene glycol over a wide range of temperatures. The heat absorption by ceria–propylene glycol nanofluids under transient, natural convective heat transfer conditions increased with ceria nanoparticle concentration. Hence ceria–propylene glycol nanofluids are suitable for cooling applications.

Time to overcome fluconazole resistant Candida isolates: Solid lipid nanoparticles as a novel antifungal drug delivery system

Antifungal therapy results in complications in management due to changes in the patterns of epidemiology and drug susceptibility of invasive fungal infections. In this study, we prepared fluconazole-loaded solid lipid nanoparticles (FLZ-SLNs) and investigated the efficacy of the optimal formulation on fluconazole (FLZ)-resistant strains of several Candida species. FLZ-SLN was produced using probe ultrasonication techniques. The morphology of the obtained SLNs was characterized by field emission scanning electron microscopy. The minimum inhibitory concentrations for the new formulations against fluconazole-resistant strains of Candida were investigated using CLSI document M27-A3. The FLZ-SLNs presented a spherical shape with a mean diameter, zeta potential and entrapment efficiency of 84.8nm, −25mV and 89.6%, respectively. The drug release from FLZ-SLNs exhibited burst release behaviour at the initial stage (the first 30min) followed by a sustained release over 24h FLZ-resistant yeast strains behaved as susceptible strains after treatment with FLZ-SLNs (≤8μg/ml). The MIC50 drug concentrations were 2μg/ml, 1μg/ml and 2μg/ml for FLZ-resistant strains of Candida albicans, Candida parapsilosis and Candida glabrata, respectively. In this study, we evaluated novel delivery systems for combating Candida strains that exhibit low susceptibility against the conventional formulation of FLZ as a first-line treatment.

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate films with low conductivity and low acidity through a treatment of their solutions with probe ultrasonication and their application as hole transport layer in polymer solar cells and perovskite solar cells

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) has been widely used as the hole transport material in optoelectronic devices. To avoid the cross talk among different crossbars, PEDOT:PSS with low conductivity is required. It thus has a high loading of the non-conductive PSSH. The PSSH-to-PEDOT weight ratio is 6 for Clevios P VP Al 4083 that is the most popular polymer as the hole transport layer. However, the acidic PSSH brings severe problems to the device stability and performance. Here, PEDOT:PSS solutions with low acidity can be prepared through a facile treatment of PEDOT:PSS solution by probe ultrasonication. Two grades of PEDOT:PSS, Clevios PH1000 and Clevios P, with a PSSH-to-PEDOT weight ratio of 2.5 were treated by probe ultrasonication. The ultrasonication can lower the viscosity and the colloidal sizes of PEDOT:PSS solutions and conductivity of PEDOT:PSS films. The pH value of probe-ultrasonicated Clevios P was 2.12, higher than that (1.77) of pristine Clevios P VP Al 4083. The ultrasonication-treated PEDOT:PSS solutions were used as hole transport layer in polymer solar cells and perovskite solar cells. The photovoltaic performances of these solar cells are comparable to that of control devices employing Clevios P VP Al 4083 PEDOT:PSS as the hole transport layer.

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes.

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G' bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy.

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G' bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy.

A highly efficient noble metal free photocatalytic hydrogen evolution system containing MoP and CdS quantum dots.

We report the construction of a highly efficient noble metal free photocatalytic hydrogen (H2) evolution system using CdS quantum dots as the light absorber and metallic MoP as the cocatalyst. MoP can be prepared by a facile temperature programmed reduction method and small clusters of MoP nanoparticles sized 10-30 nm were obtained by probe ultrasonication. The effect of synthesis conditions on the electrocatalytic and photocatalytic H2 evolution activity of MoP was investigated. The highest H2 evolution rate of 1100 μmol h(-1) can be achieved by the optimized system under visible light (λ≥ 420 nm), which is comparable to that when Pt was used as the cocatalyst. A high quantum efficiency of 45% is obtained at 460 nm irradiation.

Device level optimization of poly(vinylidene fluoride-trifluoroethylene)–zinc oxide polymer nanocomposite thin films for ferroelectric applications

Polymer nanocomposite was prepared using poly(vinylidene fluoride-trifluoroethylene) and zinc oxide (ZnO) nanopowder, which are ferroelectric in nature. Nanocomposite was prepared in various concentrations(0.2, 0.4, 0.8, and 1 wt. %) using probe ultra-sonication, followed by spin coating and annealing at 120 °C for 2 h to improve the formation of β-phase. Metal-ferroelectric-metal capacitor was fabricated using this optimized thin film as a ferroelectric layer. Device level optimization was carried out by polarization-electric field (P-E) hysteresis studies of this film, which shows polarization enhancement of composite. Various characterization techniques like atomic force microscopy, Fourier transform infra-red spectroscopy (FT-IR), Differential scanning calorimetry, and X-ray diffraction were used to study the β-phase formation of nancomposite. The capacitance–voltage (C-V) and current-voltage (I-V) characteristics were studied through varying frequency and temperature. C-V measurements show an increase of 79% in the capacitance of polymer nanocomposite, which can be used for the fabrication of ferroelectric devices.

Kinetic removal of Cr6+ by carboxymethyl cellulose-stabilized nano zerovalent iron particles

Carboxymethyl cellulose (CMC) was used in the chemical reduction method for producing dispersible nano zerovalent iron (nZVI) particles served as reactive, mobile and convenient adsorbent. CMC-stablized nZVI particles at CMC:Fe2+ = 0.0034 molar ratio were characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy assisted with probe ultrasonication dispersing tool. FTIR depicted that the CMC monomers were adsorbed onto nZVI particles primarily through carbonyl head groups via monodentate bonding. The botryoidally clusters were the predominant morphology of CMC-stablized nZVI particles under SEM observation. Those spherical particles were evenly dispersed at sizes less than 100 nm under TEM analysis. nZVI particles stabilization with CMC (at CMC:Fe2+ molar ratio of 0.0050) prevented the aggregation and resulted in high catalytic reactivity observed at pseudo-first order constant value, K1 of 0.0196 min-1 for Cr6+ removal in contaminated aqueous. This study demonstrates that CMC-stablized nZVI particles has the potential to become an effective agent for in-situ subsurface environment remediation.

Spiral assembly of amphiphilic cytarabine prodrug assisted by probe sonication: Enhanced therapy index for leukemia

In order to overcome the drawbacks of cytarabine (Ara-C), such as low lipophilicity as well as short plasma half-life and rapid inactivation, a new derivative of Ara-C was designed by incorporation into the non-toxic material, oleic acid (OA), obtaining an amphiphilic small molecular weight prodrug (OA-Ara). By a simple amidation reaction, OA-Ara was synthesized successfully with a yield up to 61.32%. It was for the first time to see that the novel prodrug molecules could assemble into the unexpectedly spiral assembly under probe ultrasonication in aqueous solution. The oil/water partition coefficient (Ko/w) and the permeability of cell membrane of the prodrug were significantly increased compared with Ara-C molecules. In addition, OA-Ara molecules were stable in various pH solutions and artificial digestives, which indicated that it could be administrated orally. Cell viability assay showed that the prodrug displayed much higher antiproliferative effect against K562 and HL60 cells due to its improvement of the lipophilicity and penetrability of cell membrane. These findings demonstrate the feasibility of utilizing structural modification to broaden the clinic application of Ara-C and thus provide an effective new therapeutic alternative for leukemia.