Reproductive toxicity of manganese dioxide in forms of micro- and nanoparticles in male rats

Background: Manganese Dioxide (MnO2) has long been used in industry, and its application has recently been increasing in the form of nanoparticle. Objective: The present study was an attempt to assess the effects of MnO2 nanoparticles on spermatogenesis in male rats. Materials and Methods: Micro- and nanoparticles of MnO2 were injected (100 mg/kg) subcutaneously to male Wistar rats (150 ± 20 gr) once a week for a period of 4 weeks, and the vehicle group received only normal saline (each group included 8 rats). The effect of these particles on the bodyweight, number of sperms, spermatogonia, spermatocytes, diameter of seminiferous tubes, testosterone, estrogen, follicle stimulating factor, and the motility of sperms were evaluated and then compared among the control and vehicle groups as the criteria for spermatogenesis. Results: The results showed that a chronic injection of MnO2 nanoparticles caused a significant decrease in the number of sperms, spermatogonia, spermatocytes, diameter of seminiferous tubes (p < 0.001) and in the motility of sperms. However, no significant difference was observed in the weight of prostate, epididymis, left testicle, estradiol (p = 0.8) and testosterone hormone (p = 0.2). Conclusion: It seems that the high oxidative power of both particles was the main reason for the disturbances in the function of the testis. It is also concluded that these particles may have a potential reproductive toxicity in adult male rats. Further studies are thus needed to determine its mechanism of action upon spermatogenesis

Multifunctional Micro- and Nanoparticles – Quo vadis ?

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64930/1/105_ftp.pd

Transfer of Individual Micro- and Nanoparticles for High- Precision 3D Analysis Using 360° Electron Tomography

A versatile approach is demonstrated, providing a general routine for an extensive and advanced 3D characterization of individually selected micro- and nanoparticles, enabling the combination of complementary and scale-bridging techniques. Quintessential to the method is the transfer of individual particles onto tailored tips using a conventional scanning electron microscope equipped with a suitable micromanipulator. The method enables a damage- and contamination-free preparation of freestanding particles. This is of significant importance for applications addressing the measurement of structural, physical, and chemical properties of specifically selected particles, such as 360° electron tomography, atom probe tomography, nano X-ray tomography, or optical near-field measurements. In this context, the method is demonstrated for 360° electron tomography of micro-/macroporous zeolite particles with sizes in the micrometer range and mesoporous alpha-hematite nanoparticles exhibiting sizes of 50–100 nm, including detailed pre- and postcharacterization on the nanoscale.“Deutsche Forschungsgemeinschaft” (DFG) within the framework of the SPP 1570 (project DFG SP 648/4-3 “3D analysis of complex pore structures using ET and high-resolution TEM”) and the research training group GRK 1896 (“In situ Microscopy with Electrons, X-rays and Scanning Probes”) as well as through the Cluster of Excellence “Engineering of Advanced Materials” at the Friedrich-Alexander-Universität Erlangen-Nürnberg (Germany)FIBJulian Losche

Plasma Assisted Generation of Micro- and Nanoparticles

In this research, the peculiarities of micro- and nanoparticles generation are considered. Two techniques of micro- and nanoparticles' formation using electric arc and underwater discharge plasma sources are proposed. Molybdenum oxide crystals were deposited on side surface of the bottom electrode (anode) of the free-burning discharge between metallic molybdenum electrodes. Friable layer of MoO3, which consists of variously oriented transparent prisms and platelets (up to few hundreds of $mu;m in size), was formed by vapor deposition around the electrode. In the second technique, plasma of the underwater electric spark discharges between metal granules was used to obtain stable colloidal solutions with nanoparticles of 20-100 nm sizes

Formation of Bioactive-Carrier Hollow Solid Lipid Micro- and Nanoparticles

In recent years, bioactive lipids (e.g., carotenoids, phytosterols, and tocopherols) have attracted a lot of interest to develop health and wellness promoting foods and beverages. However, bioactive lipids are water-insoluble and degrade easily during processing and storage, making their addition into foods and beverages challenging. The main objective of this thesis was to develop a novel green process to form bioactive lipid-carrier hollow solid lipid micro- and nanoparticles using supercritical carbon dioxide (SC-CO2). Specific objectives were to develop hollow solid lipid micro- and nanoparticles using SC-CO2 technology, and to load the hollow solid lipid micro- and nanoparticles with essential oil to develop food grade free-flowing powder antibacterial. Hollow solid lipid micro- and nanoparticles were formed from fully hydrogenated soybean oil (FHSO) using a novel process based on atomization of CO2-expaneded lipid. Hollow spheres (d50%= 278 nm) were obtained using 50 µm nozzle diameter and 200 bar expansion pressure. Shell thickness of the particles decreased with increasing pressure and nozzle diameter. Polymorphism of the particles changed from β to α by decreasing the nozzle diameter. Melting point of FHSO decreased from 69 °C to 57 °C above 120 bar in CO2, and onset melting temperature of the particles was 50 °C due to nanosize. Peppermint essential oil was successfully loaded into the hollow particles using the same process to develop food grade antibacterials. The highest loading efficiency of 47.5% was achieved at 50% initial essential oil concentration at 50 µm nozzle diameter and 200 bar expansion pressure. The release of the loaded essential oil depended on initial essential oil concentration, which was affected by the physical strength of the solid lipid shell. Essential oil-loaded particles obtained at 50% initial essential oil concentration caused 3 log decrease in growth of Pseudomonas fluorescens compared to 2 log decrease with free essential oil. Hollow solid lipid micro- and nanoparticles are promising bioactive-carriers with high loading capacity. Solid lipid shell protects the loaded bioactive from environmental conditions, and provides slow release. The free-flowing powder makes handling and storage convenient, and the simple and clean process makes the scaling up more feasible. Advisor: Ozan N. Ciftc

Formation of Bioactive-Carrier Hollow Solid Lipid Micro- and Nanoparticles

In recent years, bioactive lipids (e.g., carotenoids, phytosterols, and tocopherols) have attracted a lot of interest to develop health and wellness promoting foods and beverages. However, bioactive lipids are water-insoluble and degrade easily during processing and storage, making their addition into foods and beverages challenging. The main objective of this thesis was to develop a novel green process to form bioactive lipid-carrier hollow solid lipid micro- and nanoparticles using supercritical carbon dioxide (SC-CO2). Specific objectives were to develop hollow solid lipid micro- and nanoparticles using SC-CO2 technology, and to load the hollow solid lipid micro- and nanoparticles with essential oil to develop food grade free-flowing powder antibacterial. Hollow solid lipid micro- and nanoparticles were formed from fully hydrogenated soybean oil (FHSO) using a novel process based on atomization of CO2-expaneded lipid. Hollow spheres (d50%= 278 nm) were obtained using 50 µm nozzle diameter and 200 bar expansion pressure. Shell thickness of the particles decreased with increasing pressure and nozzle diameter. Polymorphism of the particles changed from β to α by decreasing the nozzle diameter. Melting point of FHSO decreased from 69 °C to 57 °C above 120 bar in CO2, and onset melting temperature of the particles was 50 °C due to nanosize. Peppermint essential oil was successfully loaded into the hollow particles using the same process to develop food grade antibacterials. The highest loading efficiency of 47.5% was achieved at 50% initial essential oil concentration at 50 µm nozzle diameter and 200 bar expansion pressure. The release of the loaded essential oil depended on initial essential oil concentration, which was affected by the physical strength of the solid lipid shell. Essential oil-loaded particles obtained at 50% initial essential oil concentration caused 3 log decrease in growth of Pseudomonas fluorescens compared to 2 log decrease with free essential oil. Hollow solid lipid micro- and nanoparticles are promising bioactive-carriers with high loading capacity. Solid lipid shell protects the loaded bioactive from environmental conditions, and provides slow release. The free-flowing powder makes handling and storage convenient, and the simple and clean process makes the scaling up more feasible. Advisor: Ozan N. Ciftc

In-vivo magnetic resonance imaging of hyperpolarized silicon particles

Silicon-based micro and nanoparticles have gained popularity in a wide range of biomedical applications due to their biocompatibility and biodegradability in-vivo, as well as a flexible surface chemistry, which allows drug loading, functionalization and targeting. Here we report direct in-vivo imaging of hyperpolarized 29Si nuclei in silicon microparticles by MRI. Natural physical properties of silicon provide surface electronic states for dynamic nuclear polarization (DNP), extremely long depolarization times, insensitivity to the in-vivo environment or particle tumbling, and surfaces favorable for functionalization. Potential applications to gastrointestinal, intravascular, and tumor perfusion imaging at sub-picomolar concentrations are presented. These results demonstrate a new background-free imaging modality applicable to a range of inexpensive, readily available, and biocompatible Si particles.Comment: Supplemental Material include

Micro and nanoparticles of native and modified cassava starches as carriers of the antimicrobial potassium sorbat

Cross-linked and/or acetylated cassava starches were synthesized and characterized. The acetylation increased the water retention capacity and the solubility in water while the higher level of cross-linking produced the opposite effect on starch. Native (NCS) and acetylated cassava starches (ACS) were used to generate starch micro- and nanoparticles by the dialysis technique.The nanoparticle fraction was around 1.8 g 100 g1 and 12 g 100 g1 (starch dry basis) for NCS and ACS, respectively. The nanoparticle sizes were around 23?255nm with zeta potential extending from 4 to 44mV, while the microscopic fractions ranged 5?87mm. In addition, the capacity of particles to support potassium sorbate (KS) was tested. NCS and ACS particles supported a similar quantity of KS (1400 ppm) and the presence of antimicrobial decreased the particle size for NCS. The precipitation in ethanol technique was also used to generate microparticles where the particles generated from acetylated starches were smaller (8?58mm) than those from native ones (30?227 mm). The KS content that these particles could incorporate was around 2020 ppm. The applied technique modulated the average dimension of the particles obtained, as well as the antimicrobial retention capacity. These innovative materials could bepotentially helpful for shelf life extension by the contribution to the KS stabilization to be incorporated in the bulk of food products.Fil: Alzate Calderón, Paola Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; ArgentinaFil: Zalduendo, María Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gerschenson, Lia Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; ArgentinaFil: Flores, Silvia Karina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Universidad de Buenos Aires; Argentin