Concentration Of Nanoparticles Research Articles

Synthesis of spherical and rods-like titanium oxide nanoparticles (TiO2 NPs) and evaluation of their cytotoxicity towards colon cells in vitro.

Titanium oxide nanoparticles (TiO2 NPs) are currently used as ingredients in medicines and sunscreens. Unfortunately, recent information about TiO2 NPs indicates their undesirable biological effect on colon cells. Therefore, the aim of this work was to synthesize and evaluate the physicochemical characterization of spherical (TiO2 NSs) and rods-like (TiO2 NRs) NPs, followed by assessment their cytotoxicity. For this purpose, both normal colon epithelial cells (CRL-1790) and cancerous colon cells (SW480) were used. Scanning transmission electron microscopy (STEM) showed that TiO2 NSs with a diameter of ≈10nm and TiO2 NRs with the size of the longer axis ≈25nm and shorter axis ≈3nm were obtained. Based on the selected area electron diffraction (SAED) patterns, it was found that crystalline phases were obtained for both TiO2 NPs. The UV-Vis spectra showed no contamination of TiO2 NPs. Zeta potential values were 9.7mV and 3.1mV for NSs and NRs, respectively. Cytotoxicity of TiO2 NPs was assessed using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium) test for various concentration of NPs. The cytotoxic effect for both TiO2 NPs was visible for concentration of 75μg/ml (for CRL-1790) and 50μg/ml (for SW480) and higher, and it did not depend on the shape. Moreover, both types of TiO2 NPs (in higher concentration) induce the generation of reactive oxygen species (ROS) in cells cultured with these NPs. Holotomographic microscopy studies showed increased cellular uptake of TiO2 NPs by SW480. The obtained results for the synthesized TiO2 NPs are a promising prospect for their use in biomedical application.

Single and combined chronic toxicity of cadmium and titanium dioxide nanoparticles in Aquarana catesbeiana (Anura: Ranidae) tadpoles.

The rising production and improper disposal of titanium dioxide nanoparticles (TiO2 NPs) into aquatic systems present considerable environmental challenges, especially when these particles interact with other contaminants such as cadmium (Cd). Thus, the current study aimed to evaluate the potential toxic effects on the gills, chondrocranium, body growth, and mortality of Aquarana catesbeiana tadpoles. The tadpoles were exposed to environmentally relevant concentrations of TiO2 NPs (10 µg L-1), and CdCl2 (10 µg L-1), both individually and in combination, for 30 days (chronic exposure), along with a control group. Our results indicate that the co-exposure to TiO2 NPs and Cd induced a higher mortality rate. In the gills, TiO2 NPs led to epithelial simplification, while Cd exposure resulted in stratified epithelium formation. Additionally, there were notable changes in the index of degenerative alterations for the co-exposed group and the overall organ index for the groups exposed to Cd and the mixture. The viscerocranium showed significant malformations in the ceratobranchials and reticular processes, indicating the mixture's toxicological potential during the skeletal system's development. Morphometric analysis also revealed reduced body length and abnormal body ratios in tadpoles from the co-exposure group. In conclusion, TiO2 NPs and Cd, both alone and in combination, exhibit toxicological effects in A. catesbeiana tadpoles, indicating a potential ecological risk associated with releasing these contaminants into aquatic environments.

Comparative investigation of structural properties and biological applications of chemical and biogenic synthesis of zirconium dioxide (ZrO2) nanoparticles using Passiflora edulis.

Over the last decade, the environmental and wellness cost of antibiotic drug resistance to the societies have been astounding and require urgent attention Metal oxide nanomaterials have been achieved a pull-on deal with its entire applications in biological and photocatalytic applications. The present study conducts a comparative investigation on chemical and biogenic synthesis of zirconium dioxide (ZrO2) nanoparticles aimed at enhancing their efficacy in their applications. The plant extract of Passiflora edulis act as a reducing and capping properties offering a sustainable and eco-friendly alternative. ZrO2 nanoparticles have drawn a lot of scrutiny owing to their potential uses in numerous fields, including medicine and environmental remediation. Thereby produced ZrO2 nanoparticles were synthesized by employing sustainable techniques, and their successful production and their uses were confirmed by characterization by XRD, FTIR, UV-visible spectroscopy, SEM, EDAX, PL, TEM, XPS, TGA and Raman spectroscopy. The zirconia nanoparticles synthesized using chemical and green methods exhibited ultraviolet-visible (UV-Vis) absorption maxima at 221 and 224nm, respectively, demonstrating their synthesis. X-ray diffraction research revealed that the nanoparticles possess a tetragonal shape, with mean particle sizes of 11nm and 7nm, respectively. The synthesized ZrO2 nanoparticles (ZrO2 and Ext-ZrO2) exhibited inhibitory effects against Gram-positive strains (Bacillus subtilis and Staphylococcus aureus) and Gram-negative germs (Escherichia coli and Pseudomonas aureus), with zones of inhibition measuring (12, 8mm), (8, 11mm), (12, 15mm), and (7, 12mm) correspondingly. The antitumor activity of ZrO2 and Ext-ZrO2 was assessed using human colon cancer cells (HT29). The MTT assay was employed to assess the cytotoxicity of ZrO2 nanospheres on the HT-29 cell line at various concentrations (7.5, 15.6, 31.2, 62.5, 125, 250, and 500μg/ml). The HT29 cell line exhibits a reduction in cell viability from 96% to 34% when the concentration of ZrO2 nanoparticles escalates. The photocatalytic activity of ZrO2 and Ext-ZrO2 exhibited absorbance deterioration at around 445nm, resulting in the discoloration of Rh B dye under UV light irradiation after 100min, achieving maximal degradation rates of 96% and 99%, respectively. Consequently, the synthesized ZrO2 and Ext-ZrO2 may be utilized in antibiotic formulation, pharmaceutical sectors, and photocatalysts.

Influence of metal particles shape on direct current voltage electric properties of nanofluids

It is widely recognized that the application of nanoparticles has the potential to improve the dielectric properties of transformer oil. Nevertheless, there is a scarcity of studies that have utilized pure nanofluids, and in practical applications, it is inevitable for transformer oil to become contaminated. Therefore, this study conducted tests to investigate how the shape and size of metal contaminants impact the dielectric performance of Fe3O4 nanofluids. The findings from the levitation voltage test indicate that as the size and diameter of the particle increase, the levitation voltage value measured also increases, and conversely. Moreover, a higher concentration of nanoparticles leads to a higher measured levitation voltage value. On the other hand, the breakdown voltage test results demonstrate that larger and sharper particles result in lower measured breakdown voltage values, and vice versa. The simulation outcomes regarding electric field distribution reveal that larger and sharper particles correspond to higher measured electric field values, while the opposite is true for smaller and less sharp particles.

Differential effect of cerium nanoparticles on the viability, redox-status and Ca2+-signaling system of cancer cells of various origins.

The present study aims to understand the molecular mechanism underlying the therapeutic effect of cerium nanoparticles (CeNPs) in oncology. Cancer cells were treated with different concentrations of pure nanocerium of different sizes synthesized by laser ablation. Due to the not insignificant influence of surface defects and oxygen species on the ROS-modulating properties of cerium nanoparticles, the nanoparticles were not coated with surfactants or organic molecules during synthesis, which could potentially inhibit a number of pro-oxidative effects. Reactive oxygen species (ROS) production, expression of genes encoding redox-status proteins, selenoproteins and proteins regulating cell death and endoplasmic reticulum stress (ER-stress) were investigated as indicators of the molecular mechanism of cancer cell death. Studies were conducted on the effects of cerium nanoparticles on the Ca2+ signaling system of cancer cells of different origins. Mouse fibroblasts (L-929cell line) were used as non-cancerous ("normal") cells for which a whole series of experiments were performed, and a comparative analysis of the effects of nanoceria. It was found that 75nm-sized cerium nanoparticles did not affect the redox-status and ROS production of cancer cells. In fibroblast cells, however, this nanoparticle diameter led to a deterioration of the cellular redox status and ROS production in a wide range of nanoparticle concentrations. Larger nanoparticles (100nm-sized and 160nm-sized), on the other hand, showed a different effect on cancer cells of different origins. In mouse fibroblast L-929cells, however, 100nm-sized or 160nm-sized CeNPs acted in a high concentration range to disrupt mitochondrial membrane potential and activate early apoptosis. High concentrations of CeNPs were required to increase ROS production, reduce redox-status and induce apoptosis in human A-172 glioblastoma cells compared to the hepatocellular carcinoma cell line HepG2 and the breast cancer cell line MCF-7. In the A-172 glioblastoma cells, ER-stress was also not activated and their Ca2+ signaling system was activated by a significantly higher concentration of CeNPs, which could also contribute to the formation of tolerance of this cancer cell line to nanoceria. The Ca2+ signaling system of mouse fibroblasts was found to be highly sensitive to activation by nanoceria and the cells produced Ca2+ signals with higher amplitude compared to A-172 and MCF-7cells.

Graphene oxide-enhanced photothermal therapy: laser parameter optimization and temperature modeling for hela cancer cell mortality.

Photothermal therapy, in which a laser is an effective tool, is a promising method for cancer treatment. Laser parameters, including power, irradiation time, type of laser radiation (continuous or chopped), and the concentration of the photothermal agent, can affect the efficiency of this method. Therefore, this study investigated and compared the effects of different laser parameters on the efficiency of photothermal treatment for cervical cancer, which is the fourth most prevalent cancer in women. In addition, we investigated the properties of graphene oxide (GO) synthesized as a photothermal agent under laser radiation, and its effectiveness in achieving the desired therapeutic temperature. This study examined and compared the effects of temperature, nanoparticle concentration, irradiation time, and laser power to understand their impact on heat transfer. The toxicity of graphene oxide at different concentrations in HeLa cancer cells was also evaluated. These results demonstrated low toxicity, particularly after 24h, with approximately 10% toxicity. The study explored mortality under laser irradiation at various powers and time intervals using continuous and chopped beam irradiation. In addition, a model for temperature prediction using a regression tree was presented. Finally, the combined photothermal effects of graphene oxide and laser irradiation were investigated. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test results reveal significant effects, with a mortality rate of 90% in continuous radiation with a concentration of 0.3mg/ml and 75% in chopped beam irradiation with concentrations of 0.3 and 0.4mg/ml. A regression tree model was developed to predict temperature changes based on the GO concentration, laser power, and irradiation time, providing valuable insights for optimizing photothermal therapy parameters. Statistical analysis showed that the combined effect of graphene oxide with continuous laser irradiation was more effective than chopped-beam laser irradiation. However, the chopped-beam irradiation method is expected to cause less damage to surrounding tissues. These findings indicate that photothermal therapy with graphene oxide, chopped, and continuous laser irradiation can potently treat HeLa cancer cells and pave the way for further exploration of targeted cancer treatments.

Mathematical modeling of electroosmotic flow and thermal transport in stenotic tapered arteries using finite difference method

This study investigates the electroosmotic flow and thermal transport of nanofluids, specifically aluminum oxide and titanium dioxide, within tapered arteries with stenosis. Using the finite difference method (FDM), we modeled the flow dynamics and heat transfer mechanisms under the assumption of low Reynolds numbers and mild stenosis. The study focuses on the effects of nanoparticle volume fraction, heat absorption parameters, and electroosmotic forces on blood flow, velocity profiles, and temperature distribution. Results show that increasing nanoparticle concentration and heat absorption significantly reduce flow velocity, particularly in divergent artery geometries. Additionally, the inclusion of electroosmotic effects enhances heat transfer, while the Grashof number influences central velocity. These findings offer valuable insights into optimizing nanoparticle-based therapeutic interventions for cardiovascular treatments, providing a framework for enhancing drug delivery systems and improving the efficacy of heat-based therapies. The study’s outcomes could lead to improved diagnostic tools and therapeutic strategies for managing cardiovascular diseases.

3D nanocomposites of β-TCP-H3BO3-Cu with improved mechanical and biological performances for bone regeneration applications

Recently, 3-D porous architecture of the composites play a key role in cell proliferation, bone regeneration, and anticancer activities. The osteoinductive and osteoconductive properties of β-TCP allow for the complete repair of numerous bone defects. Herein, β-TCP was synthesized by wet chemical precipitation route, and their 3-D porous composites with H3BO3 and Cu nanoparticles were prepared by the solid-state reaction method with improved mechanical and biological performances. Several characterization techniques have been used to investigate the various characteristics of fabricated porous composites. SEM and TEM studies revealed the porous morphology and hexagonal sheets of the β-TCP for the composite THC8 (82TCP-10H3BO3-8Cu). Moreover, the mechanical study showed excellent compressive strength (188 MPa), a high Young’s modulus (2.84 GPa), and elevated fracture toughness (9.11 MPa.m1/2). An in vitro study by MTT assay on osteoblast (MG-63) cells demonstrated no or minimal cytotoxicity at the higher concentration, 100 µg/ml after 24 h and it was found a more pronounced result at 20 µg/ml on increasing the concentration of Cu nanoparticles after incubating 72 h. The THC12 composite showed the highest antibacterial potency exclusively against B. subtilis. S. pyogene, S. typhi and E. coli. at 10 mg/ml, indicating its potential effectiveness in inhibiting all of these pathogens. Genotoxicity and cytotoxicity tests were also performed on rearing Drosophila melanogaster, and these findings did not detect any trypan blue-positive staining, which further recommended that the existence of composites did not harm the larval gut. Therefore, the fabricated porous composites THC8 and THC12 are suitable for bone regrowth without harming the surrounding cells and protect against bacterial infections.

Studies on biological activities with effect of temperature on curry and neem leaves nanoparticles

Curry and neem leaves nanoparticles were designed to estimate the biological activities such as conductivity, pH-values, transmission percent, concentration and temperature. An experiment was carried out based on diffusion method. Results show that hydrogen ion concentration (pH) for the distilled water was neutral (7.0), the average pH-value of CU (7.44) and NE (7.42).The results indicated that the neem and curry leaves nanoparticles shown nearly same pH- value. It implies that antacid potentials present which will be caused by biological infective resistance to human beings. This kind of activity in general found to be rheumatic reluctance for many orthopedically pains. Significant differences were found with the effect of temperature, conductivity, concentration and pH-values of the curry and neem leaves nanoparticles. Concentration of the neem nanoparticles increases the conductivity also increases but the concentration of the curry leaves nanoparticles increases the conductivity will show interweave. It indicates that conductivity levels were responsible for the biological activity of the sample and positive significant (p<0.05) relationship between the conductivity of the curry and neem leaves nanoparticles.

Incidental nanoparticle characterisation in industrial settings to support risk assessment modelling.

Research on nanoparticle (NP) release and potential exposure can be assessed through experimental field campaigns, laboratory simulations, and prediction models. However, risk assessment models are typically designed for manufactured NP (MNP) and have not been adapted for incidental NP (INP) properties. A notable research gap is identifying NP sources and their chemical, physical, and toxicological properties, especially in real-world settings. This work aims to provide insights into the release and physico-chemical properties of INP while contributing to improving models for INP release. INP release was evaluated through a case study in a ceramic tile firing facility, where aerosol (10nm - 10μm) properties were determined. The Control Banding (CB) Nanotool model was applied to test outputs based on provided input parameters. RESULTS: demonstrate the constant generation and release of INP during tile firing, with NP concentrations up to 68711/cm³ and mean diameters of 37nm, with 95% smaller than 100nm. Particle morphology was mostly spherical, suggesting nucleation from precursor gases as the main formation mechanism. INP chemical composition was driven by primary ceramic components, while trace elements like Ni and Ti exhibited size-dependent patterns. In vitro cell viability tests indicated low to medium cytotoxicity of PM2 aerosols, decreasing human alveolar epithelial cell viability in a concentration-dependent manner. Applying the risk model with varying input parameters revealed that the risk level (RL) based on severity scores decreased when aerosol size distribution data were used, illustrating the model's sensitivity to input variables. We conclude on the need for comprehensive experimental datasets to support risk assessment models and achieve effective risk management strategies in real-world scenarios.

Chitosan-Based Zinc Oxide and Silver Nanoparticles Coating on Postharvest Quality of Papaya

The study aimed to investigate the effects of chitosan-based zinc oxide and silver nanoparticles coating on physicochemical properties of papaya and to optimize nanoparticles concentrations for extending its postharvest shelf life. The experiment was conducted in February, 2022 at the Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Kathmandu, Nepal, using a Completely Randomized Design (CRD) with nine treatments and three replications. The treatments consisted of different concentrations (50 ppm, 100 ppm, 150 ppm, and 200 ppm) of either Zinc oxide and silver nanoparticles, along with a control. Zinc oxide and silver nanoparticles were synthesized from banana peel extract and the average crystalline sizes were found to be 22.30nm and 4.46nm, respectively. Fruits were dipped in 1.5% (w/v) chitosan with 50–200 ppm of zinc oxide and silver nanoparticles and then stored at ambient temperature (14±1.6°C) and ~75% RH. The nanoparticles coatings slowed changes in total soluble solids (TSS) and total titratable acidity (TTA), delaying ripening. Treated fruits showed reduced physiological loss in weight and maintained firmness better than control, with firmness decreasing to 4.79 kg in untreated fruits compared to 7.35 kg in coated fruits on 18th day of storage. Coated fruits retained more ascorbic acid, and the storage life increased by 8 and 9 days with 150 and 200 ppm treatments, respectively. However, consumer preference declined for concentrations above 150 ppm. Thus, 100–150 ppm chitosan-based zinc oxide/silver nanoparticles are found to be effective for extending shelf-life and maintaining physiochemical characteristics of papaya. However, its residual and health-related dimensions need to be extensively studied before its commercial application. SAARC J. Agric., 22(2): 181-196 (2024)

Antibacterial Activity and Characterization of CaO Nanoparticles Synthesized from Eggshell

Introduction: With an average crystallographic size of 8.67 nm, we studied the antibacterial properties of CaO nanoparticles against microorganisms. The CaO NPs used in this study were synthesized using a simple soft chemical method. Methods: To assess antibacterial activity, three methods were employed: the live count (LC) method, the agar cup method, and the minimum inhibitory concentration (MIC) approach. The CaO nanoparticles used in this study were produced using a simple soft chemical method. Results: TEM study revealed that the application of nanoparticles disrupted the cell walls of pathogens. Conclusion: We can conclude from this work that the lethal effect rises with CaO nanoparticle concentration. According to this research, CaO NPs seem like a good option for creating novel antibacterial drugs that are more effective against infections. The dose amount may be used in therapeutic settings. Considering this, the application of CaO nanoparticles as antibacterial agents could result in effective in vivo experiments.

Extraction of lignin from Duabanga grandiflora and its valorization for nanocomposite development with enhanced mechanical and UV shielding properties

Abstract In this study, we report on extracting lignin (EL) from Duabanga grandiflora (Khukon), an untapped wood source, and its transformation into nano-lignin (NL) to create durable and thermally stable composites. Utilizing ultrasonication, we synthesized spherical lignin nanoparticles with an average size of 8 nm, as verified by High-Resolution Transmission Electron Microscopy (HRTEM). These nanoparticles were integrated into a polyvinyl alcohol (PVA) and guar gum (GG) matrix, resulting in PVA-GG-nano-lignin (PGNL) composites. Polyvinyl alcohol (PVA)-Guar gum (GG) nanocomposite films containing various contents of lignin nano-particles (1, 2 and 3 wt%) were formulated by a simple solvent cast method and cross-linked by adding borax. Addition of 1wt% lignin nanoparticles brought in the composite films with 29.8MPa tensile strength and 139.3% elongation at break. Compared to PVA-GG-lignin (PGL) composites, the PGNL composites exhibited a 59.4% increase in tensile strength and enhanced elongation at break and good thermal degradation properties. Notably, the PGNL composite films were transparent but could shield 99.9% of the UV-A (320-400 nm) and UV-B (280-320 nm) radiations, marking a significant advancement in UV protective materials. Our innovative use of Duabanga grandiflora-derived nano-lignin in a dual-polymer network not only underscores the potential of renewable resources in high-performance applications but also aligns with the principles of a circular bioeconomy by offering a sustainable solution for effective UV protection.

3D convective flow in a hybrid nanofluid filled bi-truncated-pyramid equipped with adiabatic cylinders

This study consists of an investigation of the 3D convective flow of hybrid nanofluids (HNFs) within a bi-truncated pyramid equipped with adiabatic cylinders, with a focus on the enhancement of natural convection (NC) heat transfer (HT). The use of HNFs, which is based on the combination of two different nanoparticles (NPs), provides improved thermal conductivity and stability, and leads to significant advantages in thermal management systems. Numerical simulations based of the FEM were performed to analyze the effects of Rayleigh number (Ra), nanoparticle volume fraction (φ), and cylinders size (D) on the heat transfer and fluid flow (FF) within the pyramid. The results showed that at higher Ra and nanoparticle concentrations a significant enhancement of the HT occurs, and the average Nusselt number (Nua) was increased by up to 23% at a Ra = 106 and φ = 0.045. Concerning the adiabatic cylinders, it was found that the optimal cylinder diameter is D = 0.15, (balance between flow disturbance and heat transfer rate). The outputs of the current study are valuable in the optimization of the hybrid nanofluid applications for advanced thermal management solutions.

Performance and emissions of diesel engine combustion lubricated with Jatropha bio-lubricant and MWCNT additive

Vegetable oil-based lubricants, modified through transesterification and epoxidation, present a sustainable alternative to mineral lubricants for transport and industrial use. This study evaluates epoxidized jatropha oil (EJA) enhanced with multi-walled carbon nanotubes (MWCNT) as a bio-lubricant for compression ignition engines. MWCNT, dispersed in EJA using an ultrasonic probe sonicator with Triton X-100 as a surfactant, was tested at nanoparticle concentrations from 0.5 to 2 wt%. Engine performance and emission characteristics were assessed using SAE 20W40, EJA, and EJA-MWCNT in a four-stroke diesel engine. Results showed that EJA with 2 wt% MWCNT reduced friction power by 39.13% compared to SAE 20W40 and decreased brake specific energy consumption by 6.11%, while lowering emissions of hydrocarbons, carbon monoxide, and smoke. These findings highlight EJA-MWCNT as a promising lubricant for diesel engines, enhancing efficiency and reducing pollutants, making it a viable eco-friendly substitute for diminishing petroleum resources.

Optimization of exogenous CeO2 nanoparticles on Pak choi (Brassica rapa L. var. chinensis) to alleviate arsenic stress

Arsenic (As) is a regulated hazardous substance that persists in the environment, causing issues related to environmental health, agriculture, and food safety. Cerium oxide nanoparticles (CeO2 NPs) are emerging sustainable solutions for alleviating heavy metal stress. However, their effectiveness and optimization for foliar application in reducing As stress, especially in Pak choi, has not been reported yet. Hence, this study aims to examine the effects of foliar application of CeO2 NPs (75,000,000, 150,000,000, and 300,000,000 ng/L) on the growth, nutrient availability, and antioxidant enzymatic activities of Pak choi plants under As stress. The findings showed that foliar application of 75,000,000 ng/L CeO2 NPs significantly increased shoot length (77.32%), root length (80.98%), and number of leaves (80.23%) as compared to control without NPs. The lowest dose of CeO2 NPs (75,000,000 ng/L) increased antioxidant enzyme activities such as peroxidase (86.10%), superoxide dismutase (81.48%), and catalase (52.07%), while significantly reducing malondialdehyde (44.02%), hydrogen peroxide (34.20%), and electrolyte leakage (43.53%). Furthermore, foliar application of 75,000,000 ng/L CeO2 NPs significantly increased the content of zinc (81.02%), copper (56.99%), iron (88.04%), manganese (68.37%), magnesium (76.83%), calcium (61.16%), and potassium (84.91%) in leaves when compared to control without NPs. The same trend was observed for shoot and root nutrient concentrations. Most importantly, 75,000,000 ng/L CeO2 NPs foliar application significantly reduced shoot As (45.11%) and root As (20.89%) concentration compared to control, providing a reassuring indication of their potential to reduce As concentration in plants. Our study’s findings are of utmost importance as they indicate that lower concentrations of foliar-applied CeO2 NPs can be more effective in enhancing crop nutrition and reducing heavy metals than higher concentrations. This article is intended to present critical issues of As contamination in agricultural soils, which imposes substantial risks to crop productivity and food security.

Gadolinium oxide nanoparticles as a multimodal contrast enhancement agent for pre-clinical proton imaging

Orthotopic tumor models in pre-clinical translational research are becoming increasingly popular, raising the demands on accurate tumor localization prior to irradiation. This task remains challenging both in x-ray and proton computed tomography (xCT and pCT, respectively), due to the limited contrast of tumor tissue compared to the surrounding tissue. We investigate the feasibility of gadolinium oxide nanoparticles as a multimodal contrast enhancement agent for both imaging modalities. We performed proton radiographies at the experimental room of the Trento Proton Therapy Center using a MiniPIX-Timepix detector and dispersions of gadolinium oxide nanoparticles in sunflower oil with mass fractions up to 8wt%. To determine the minimum nanoparticle concentration required for the detectability of small structures, pCT images of a cylindrical water phantom with cavities of varying gadolinium oxide concentration were simulated using a dedicated FLUKA Monte Carlo framework. These findings are complemented by simulating pCT at dose levels from 80 mGy to 320 mGy of artificially modified murine xCT data, mimicking different levels of gadolinium oxide accumulation inside a fictitious tumor volume. To compare the results obtained for proton imaging to x-ray imaging, cone-beam CT images of a cylindrical PMMA phantom with cavities of dispersions of oil and gadolinium oxide nanoparticles with mass fractions up to 8wt% were acquired at a commercial pre-clinical irradiation setup. For proton radiography, considerable contrast enhancement was found for a mass fraction of 4wt%. Slightly lower values were found for the simulated pCT images at imaging doses below 200 mGy. In contrast, full detectability of small gadolinium oxide loaded structures in xCT at comparable imaging dose is already achieved for 0.5wt%. Achieving such concentrations required for pCT imaging inside a tumor volume inin-vivoexperiments may be challenging, yet it might be feasible using different targeting and/or injection strategies.

Zinc-doped hydroxyapatite loaded chitosan gelatin nanocomposite scaffolds as a promising platform for bone regeneration

The advancement in the arena of bone tissue engineering persuades us to develop novel nanocomposite scaffolds in order to improve antibacterial, osteogenic, and angiogenic properties that show resemblance to natural bone extracellular matrix. Here, we focused on the development of novel zinc-doped hydroxyapatite (ZnHAP) nanoparticles (1, 2 and 3 wt%; size: 50-60 nm) incorporated chitosan-gelatin (CG) nanocomposite scaffold, with an interconnected porous structure. The addition of ZnHAP nanoparticles decreases the pore size (∼30 µm) of the CG scaffolds. It was observed that with the increase in the concentration of ZnHAP nanoparticles (3 wt%) in CG scaffolds, the swelling ratio (1760% ± 2.0%), porosity (71% ± 0.98%) and degradation rate (35%) decreased, whereas mechanical property (1 MPa) increased, which was better as compared to control (CG) samples. Similarly, the high deposition of apatite crystals especially CG-ZnHAP3nanocomposite scaffold revealed the excellent osteoconductive potential among all other scaffolds. MC3T3-E1 osteoblastic cells seeded with CG-ZnHAP nanocomposite scaffolds depicted better cell adhesion, proliferation and differentiation to osteogenic lineages. Finally, the chorioallantoic membrane (CAM) assay revealed better angiogenesis of ZnHAP nanoparticles (3 wt%) loaded CG scaffolds supporting vascularization after 7th day incubation in the CAM area. Overall, the results showed that the CG-ZnHAP3nanocomposite scaffold could be a potential candidate for bone defect repair.

Optimizing bioconvective heat transfer with MHD Eyring–Powell nanofluids containing motile microorganisms with viscosity variability and porous media in ciliated microchannels

Purpose This paper aims to optimize bioconvective heat transfer for magnetohydrodynamics Eyring–Powell nanofluids containing motile microorganisms with variable viscosity and porous media in ciliated microchannels. Design/methodology/approach The flow problem is first modeled in the two-dimensional frame and then simplified under low Reynolds number and long wavelength approximations. The numerical method is used to examine the impact of thermal radiation, temperature-dependent viscosity, mixed convection, magnetic fields, Ohmic heating and porous media for velocity, temperature, concentration and motile microorganisms. Graphical results are presented to observe the impact of physical parameters on pressure rise, pressure gradient and streamlines. Findings It is observed that the temperature of nanofluid decreases with higher values of the viscosity parameter. It is absolutely in accordance with the physical expectation as the radiation parameter increases, the heat transfer rate at the boundary decreases. Nanoparticle concentration increases by increasing the values of bioconvection Rayleigh number. The density of motile microorganisms decreases when bioconvection Peclet number is increased. The velocity of the nanofluid decreases with higher value of Darcy number. With increase in the value of bioconvection parameter, the flow of nanofluid is increased. Originality/value The bioconvective peristaltic movement of magnetohydrodynamic nanofluid in ciliated media is proposed. The non-Newtonian behavior of the fluid is described by using an Eyring–Powell fluid model.

Effect of administration of nanoparticles of human chorionic gonadotropin on testicular hemodynamics, testicular volume, testicular echotexture, and circulating testosterone and nitric oxide in pubescent goat bucks under heat stress conditions

The current study investigated the effect of a single administration of human chorionic gonadotropin hormone (hCG) and its nanoparticles (NPs) on testicular hemodynamics using Doppler ultrasonography, testicular volume, testicular echotexture (PIX), and circulating testosterone and nitric oxide (NO) in pubescent goat bucks during summer months. Fifteen Baladi goats were divided into three groups (5 in each) and subjected to a single intramuscular administration of one ml of physiological saline ( control group), one ml containing 500 IU of hCG (hCG group) or one ml containing 125 IU of hCG NPs (hCG NPs group). Testicular hemodynamics assessment was done just before administration (0 h), and at 2, 4, 6, 24, and daily till 7 days after administration. Testicular volume and PIX were measured and analyzed by B-mode ultrasonography and computer analysis software. Testosterone and NO concentrations were measured using commercial kits. Results revealed significant decreases (P ˂0.05) in Doppler indices values (resistance index and pulsatility index) especially at 24 h in the hCG group (0.314 ± 0.01, 0.382 ± 0.01, respectively) compared with the hCG NPs group (0.428 ± 0.01, 0.567 ± 0.02, respectively), and the control group (0.464 ± 0.006, 0.64 ± 0.01, respectively). There were significant increases (P < 0.001) in testicular volume, PIX, testosterone, and NO concentrations in hCG NPs and hCG groups compared to the control group. There were no significant differences between the hCG NPs and hCG groups (P ˃ 0.05) in testicular volume and PIX, while testosterone significantly increased in the hCG group compared to the hCG NPs group and NO was significantly increased in the hCG NPs group compared to the hCG group. In conclusion, a single administration of hCG or its NPs improved testicular vascularization, testicular volume, and circulating testosterone and NO in pubescent goat bucks. So, hCG NPs could be recommended for improving the reproductive performance of goat bucks under heat-stress conditions.