University of Belgrade, Serbia
Ferro electric properties of BiFeO3 ceramics with cation substitutions at Bi-site (La3+, Eu3+) and Fe-site (Nb5+, Zr4+)
Dr. Aleksandar Radojkovic is a senior research fellow at the Institute for Multidisciplinary Research, University of Belgrade. he as worked Senior Research Fellow at, Institute for Multidisciplinary Research in 2022. Research Fellow, Institute for Multidisciplinary Research in 2014. Research Assistant, Institute for Multidisciplinary Research in 2010.His Education Ph.D. in Materials science, Faculty of Technology and Metallurgy, University of Belgrade, Dissertation title: “Properties of yttria doped barium cerium oxide ceramics as an electrolyte for solid oxide fuel cells”.in 2014He Studied BSc in Norwegian language and Scandinavian literature, Faculty of Philology, the University of Belgrade in 2004He studied MSc in Inorganic Chemical Engineering, Faculty of Technology and Metallurgy, the University of Belgrade in 2003His research interest is Proton conductivity and electrical properties of BaCeO3-based materials and their application in solid oxide fuel cells; Synthesis and characterization of multiferroic BiFeO3, using doping and codoping as a strategy for tailoring its ferroelectric and magnetic properties; Development of hybrid composites based on biopolymers and metal oxides as environmentally safe pesticides.
BiFeO3 is one of few multiferroic perovskites that exhibits both magnetic and ferroelectric properties at room temperature. However, it is also distinguished by high leakage current, low remnant electric and magnetic polarization, and high electric coercive field. These features keep it away from any practical use in electronics. Therefore, many attempts have been done to improve the properties of BiFeO3 by Bi- or Fe-site doping or by both. Previous investigations suggest that doping with Nbat Fe-site can positively affect the magnetic behavior of BiFeO3 and decrease the leakage current.
In this study, a variety of cation substitutions at Bi-site (La3+, Eu3+) and Fe-site (Nb5+, Zr4+) were examined with the aim to investigate their possible synergism and benefit for the ferroelectric properties. The role of the cations with higher valence is to suppress the formation of structural defects during syntheses, such as oxygen and bismuth vacancies. These defects are responsible for high leakage currents, and consequently, low breakdown voltages characteristic of the pure BiFeO3. On the other hand, rare-earth cations at the Bi-site usually enable densification of the ceramics in a wider range of temperatures, preventing bismuth loss and formation of defects and secondary phases during sintering. However, do pant concentrations above 10–15mol% may give rise to transition from polar, rhombohedral (R3c) to non-polar, orthorhombic (Pnma) symmetry.
The carefully selected compositions of doped BiFeO3 were synthesized by a simple hydro-evaporation method. The ceramics samples were characterized using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and polarization techniques, including leakage current measurements. Although it was shown that the introduction of Nb5+or Zr4+decreased the leakage current, they surprisingly deteriorated the ferroelectric properties even at concentrations as low as 1 mol%. This effect was more pronounced for the samples containing Nb. On the contrary, both La3+ and Eu3+(incorporated at the Bi-site) improved the ferroelectric properties as their concentrations increased, whereby the La-doped samples exhibited higher remnant electric polarization at observed electric fields. The highest remnant electric polarization of31.9 µC/cm2at 150 kV/cm, was measured for Bi0.85La0.15Fe0.998Zr0.002O3, indicating the synergetic effect of La3+ and Zr4+, which is limited to very low Zr4+concentrations.
Vajresh Kumar N
Indian Institute of Science, India
Functionalization of Fiber Bragg Grating Using Different Coating Methods
Optical fiber gratings have gone through an improved growth of development in the current years in track with the observation of narrow-band reflection in the photosensitive core region of silica optical fiber which is Germanium or boron-doped. Fiber Bragg grating is a periodic modulation of the refractive index along with the core of a photosensitive fiber. The refractive index changes are made by exposing the fiber to the interference pattern of Ultraviolet light. FBGs are less sensitive to refractive index (RI) variations of the external medium as the fiber is covered by cladding, limiting the application of FBGs being used in biological and chemical sensing applications. The surface of the e-FBG is modified with functionalized coatings based on the target to detect the change in RI using different coating techniques and different nanomaterials such as AgNP, AuNP, etc., and is characterized. This sensing probe can be used in different biological sensing applications.
Keywords: Fiber Bragg grating, coating techniques, nanoparticles, functionalization,
Tarbiat Modares University, Iran
Oocyte Characterization Using Microfluidic Channel
Dr. Davood Fathi received a B.Sc. degree in the field of electronic engineering from Amirkabir University of Technology, Tehran, Iran, in 1990, and an M.Sc. degree in the field of biomedical engineering from Sharif University of Technology, Tehran, Iran, in 1994. After a couple of years working in the industry, he worked toward a Ph.D. degree between 2006-2009 in the field of nanotechnology with the Nanoelectronic Center of Excellence, Thin Film and Photonics Research Laboratory, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran.
Dr. Fathi has joined in 2010 as a member of the faculty of the Department of Electrical and Computer Engineering, Tarbiat Modares University (TMU), Tehran, Iran.
He has been the reviewer for more than 20 international journals including IEEE, OSA, Elsevier, Springer, John Wiley, and so on.
His current research interests include Nanoelectronics; Nanotechnology; Nanophotonics and Optoelectronics; Nano-biotechnology; Nano-microfluidics; Biosensors; Solar Energy.
He is also the author or co-author of more than 85 scientific journal and conference papers in various fields of Nanoelectronics, Nanotechnology, and Photonics.
Dr. Fathi is currently an Associate Professor in his department.
He has supervised more than 40 M.Sc. students and 5 Ph.D. students. One Ph.D. student and 3 M.Sc. students are currently working on an interdisciplinary topic of oocyte evaluation based on the design and fabrication of nano-micro fluidic systems.
He has been selected as an invited or keynotes speaker for several international conferences such as CCET-2022, CCT-2022, Nanotechnology 2022, Microfluidics 2022, Material Chemistry 2022, and so on.
Oocyte development is largely dependent on its mechanical properties. Cell mechanics control the outcome of cell division. In recent years, various techniques such as micropipette aspiration (MPA) and optical tweezers are being used to measure the mechanical properties of membranes. The traditional MPA systems, however, have low throughputs and limited potential for automation and require bulky infrastructures. These methods have been used to investigate the mechanical characteristics of single cells including the elastic and viscoelastic properties, etc. In MPA methods, by applying a specific suction pressure, the cell aspirates into a micropipette. The amount of aspirated surface into the pipette is then recorded and measured using an electron microscope over time. During the aspiration, any leakage between the cell and the micropipette needle causes an error in the measurement of suction pressure. Due to the complexity of pressure measurement, the accuracy of the results largely depends on the skill of the user of the equipment. Furthermore, surface water evaporation and bubbles in the micropipette lead to errors in measuring the applied pressure. Although the aspiration force is applied to the entire oocyte volume, since the direction of the applied pressure is random, the average values for the measured mechanical characteristics of the entire cell are considered. On the other hand, these techniques are generally labor-intensive and time-consuming, typically involving a difficult process of manipulation.
Microfluidic channels have been developed in the past two decades for various biomedical applications, due to advantages such as real-time analysis, system integration, transparency for direct optical access, labor, precise control, lower cost, and reduced space. Furthermore, microfluidic channels can be integrated with other techniques and can enhance traditional cell analysis methods. Biological cell analysis and characterization can be performed based on the shape, size, and deformability of single cells in microfluidic chips. Various methods have been applied for microfluidic single-cell trapping including hydrodynamic trapping, dielectrophoresis trapping, chemical trapping, gel trapping, magnetic trapping, acoustic trapping, laser trapping, etc.
In this lecture, I present a new method for designing and manufacturing microfluidic channels in order to measure and evaluate the mechanical properties of mouse oocytes. The proposed process has the advantages of high accuracy and fast and easy operation. In our proposed technique, the oocytes are trapped in a specific channel, as shown in Fig. 1.
Although the designed and manufactured structure has microfluidic dimensions, in the design and analysis of the structure, knowledge and software environment in the field of nanotechnology and nanoelectronics have been used.
University of Pisa, Italy
Nanoplastics toxic to plants Early evidence and concerns
Carmelina Spanò joins the University of Pisa as a researcher in the Department of Biology. She received a degree in Biological Sciences from the University of Pisa, cum laude, and the title of Ph.D. in Agricultural Biology. She has held many courses in plant physiology (Plant Biochemistry, Plant Biotechnology, Plant Physiology, Transgenesis in plants, and currently Strategies of resistance in plants). Her primary research interests have been in plant response to abiotic stressors in laboratory-controlled conditions, with a particular interest in studying oxidative stress and antioxidant response in plants under different physiological or stress conditions. In the last decade, her interest has turned to the study of the effects of nanomaterials on plants. In her free time, she practices tai chi and brisk walking, and reads many novels, especially detective stories; she is also fond of jazz music.
Plastics are used in many industrial sectors and in several everyday life products. The extensive use and the poor attention to their disposal and recycling are causing the production of massive amounts of waste, with possible global contamination of environmental matrices. As known, plastics are not biodegradable and remain in the environment for long periods undergoing aging processing with fragmentation into smaller pieces, up to micro (less than 5 mm) and nano (less than 100 nm) particles dimension, the smaller fractions being of specific concern. The possible entry of these particles into the food chain through plants represents a problem to deal with to improve food safety for humans and animals. To investigate the interactions between these particles and plants, we used a multidisciplinary approach in which seeds of the model crops Allium cepa L. and Oryza sativa L. were treated with different concentrations of polystyrene nano plastics (PS-NPS), chosen as model particles, as polystyrene is among the six more used plastics, widely diffused in all the terrestrial environments including agro-ecosystems. Under short-term conditions, phytotoxicity, genotoxicity, and cytotoxicity effects were assessed during germination and the early stages of seedling growth. Thanks to our integrated approach it was possible to highlight that PS-NPS can impair seed germination and seedling growth. They can be taken up by the root and translocated to the above-ground part of seedlings, even entering inside cells, where their presence is associated with ultra structural damages and genotoxicity. A different concentration/localization of main oxidative stress markers has been recorded, along with the induction of an enzymatic antioxidant response. Our results suggest that damages detected could be due not only to changes in the production/diffusion of oxidative stress markers but also to a possible direct effect of PS-NPS, able to overcome plant cell barriers. Further studies under long-term conditions, with a particular focus on the edible parts of the plant, will be useful to better clarify the impact on the environment and health of nano plastics, but their ability, even in short-term experiments, to enter inside crop plants, and possibly into the food chain is a matter of considerable concern.
Shirley Priscilla Onkani
Vaal University of Technology, South africa
Comparative study of the Photodegradation of Chloramphenicol under visible LED irradiation using pristine and Ag doped TiO2 and ZnO photocatalysts
Onkani Shirley Priscilla studied Chemistry at the Vaal University of Technology, South Africa, and graduated with an MTech in 2020. She has joined Prof. Fanyana's research group at the Nanotechnology, Catalysis, and Organic Chemistry Laboratory since 2016. Currently pursuing a Ph.D. in inorganic chemistry and environmental focus on the removal of emerging organic pollutants at the same institution and under the same supervision. She has so far published one research article in a peer-reviewed journal (J.Environ Manage). She has also mentored two undergraduate research projects and has four years of work experience in industry and academia.
Unregulated discharge of antibiotics has become a global concern for water pollution, of which Chloramphenicol known as an emerging pollutant is the pollutant study herein. This work describes a comparative study of the degradation of chloramphenicol (CAP) in an aqueous solution using pristine and Ag-doped semiconductor photocatalysts obtained from TiO2 and ZnO. Varying weight percentages (2.5, 5, and 7.5 wt. %) of Ag nanoparticles were doped on the semiconductor photocatalysts via the sol-gel method and then calcined at 500? for 3h. The pristine and Ag-doped semiconductor photocatalysts were characterized using UV-Vis, diffuse reflectance spectroscopy (UV-DRS), photoluminescence spectroscopy (PL), Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM). These techniques confirmed the successful synthesis of the pristine and Ag-doped materials. The photocatalytic activities of all materials used for the degradation of CAP were carried out under LED visible light irradiation for 2h; and the effects of various operating parameters (such as doping agent Ag, catalyst loading, pH, and pollutant concentration) were also investigated. The result showed that enhanced CAP degradation in Ag-doped in comparison to the pristine materials was most suitable for CAP degradation, especially at low pollutant concentrations. The effect of pH on the CAP degradation was very versatile, depending on the catalyst introduced in the solution. Lower loadings of the photocatalysts were usually more effective for CAP degradation and the degradation trend in TiO2 was 5 wt. % Ag doped > 7.5 wt. % Ag doped > 2.5 wt. % Ag doped > Pristine, while it was 2.5 wt. % Ag doped > 5 wt. % Ag doped > 7.5 wt. % Ag doped > Pristine in the ZnO.
Indian Institute of Science, India
Immobilized functionalized silver nanoparticles to detect Chromium in water.
A simple yet effective way to detect chromium, one of the major water contaminants by using Tartaric acid-functionalized silver nanoparticles immobilized on the surface of etched Fiber – Bragg grating sensors (e-FBG). The target analyte and functionalized nanoparticle could be further confirmed by performing UV-Visible spectroscopic analysis while the structure of the coating surface could be analyzed by SEM imaging.figure1 provides an insight into the working principle of the developed sensor. The limit of detection(LOD) falls well within the permissible range. The sensitivity and linearity of the sensor show promising signs of developing into a field-deployable unit.
Keywords: Chromium detection, silver naoparticle,functionalization, e-FBG.
AlFaisal University, Saudi Arabia
Upconversion Nanoparticle-Mediated Optogenetics as a Potential Therapy for Epilepsy
Monica Alexander-Sylvester is an American and Saudi-licenced general practitioner working at a private primary care center in Riyadh, Saudi Arabia. She is heavily involved in neuroscience research, specifically in the application of nanomedicine. The application of nanomedicine to the drug delivery of neurological diseases is one of her main interests. Currently, her focus is on the treatment of epilepsy using optogenetics. Optogenetics has several limitations that can be addressed with the promise of nanoparticles.
Optogenetics has revolutionized a new era of effective and targeted control over neural function. Combining both optics and genetics allows neurons to be controlled over specific spatial and temporal activity. However, it is limited since visible light cannot penetrate deeper brain structures. Upconversion nanoparticles (UCNPs) will up-convert lower-energy photons into one high-energy photon by absorbing the penetrable near-infrared (NIR) light and emitting wavelength-specific visible light, which will result in the manipulation of overexcited neurons. To overcome these limitations, we propose using a non-toxic nanocomposite (Fe3O4-PEG/rGO). Using the Fe3O4-PEG/rGO nanocomposite has the dual effect of delivering the NpHR Optogene and UCNPs to inhibit targeted excitatory neurons within the Temporal Lobe, consequently dampening seizures.
Sharif University of Technology, Iran
The investigation of photocatalytic properties ofNi0.8CO0.2/Zn0.4Cd0.6S/g-C3N4as a nano-photocatalystfor pollutants, degradation, andH2 generationbywater splitting
Fatemeh Sousani joined the department of material science and engineering of the Shariff University of Technology as a doctoral candidate in September 2020. Her doctoral thesis is entitled “the performance improvement of H2 production via water splitting with NixCo1-x/ZnxCd1−xS/g-C3N4 nano hybrid photocatalysts” under the supervision of Prof.SayedKhatiboleslam Sadrnezhaad and Dr. Parvin Abachi. She received her master’s degree in 2017. She worked on the design of the germanium–carbon antireflection coatings. She had also a research project to investigate the thermal stability properties of germanium-carbon coatings. The results of her master’s thesis were published in reputable ISI journals.
Graphitic carbon nitride (g-C3N4) is a promising metal-free visible-light photocatalyst due to its strong visible light response, high thermal and chemical stability, and available low-cost raw materials. This substance has gained significant attention for the degradation of pollutants and photocatalytic water splitting for H2 production under visible light. Nevertheless, due to the relatively large band-gap, low charge-carrier mobility, and thus limited effective use of sunlight, the photocatalytic hydrogen evolution efficiency of pristine g-C3N4is still unfavorable. Several strategies, such as morphological control of g-C3N4, creating heterojunctions with semiconductors, and doping with other elements have improved its photocatalytic efficiency. This study's aim is to improve the photocatalytic performance of g-C3N4for degradation of pollutants and hydrogen evolution by creating Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4 nano-photocatalyst that makes it more effective under visible-light irradiation. Here, Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4nano-photocatalyst is produced via a facile hydrothermal and chemical reduction method. Then, the morphology, structural, optical, and photocatalytic properties of the nanohybrid were characterized by field emission scanning electron microscope (FE-SEM), X? ray diffraction (XRD), Brunauer–Emmett–Teller (BET), UV? vis diffuse reflectance absorption spectra (DRS) and photoluminescence (PL). With the formation of Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4, the bandgap energy of the g-C3N4 decreases from 3.01 to 2.77 eV, and the absorption edge increases from 412 to 448 nm. The Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4absorption edge is located between g-C3N4 and Zn0.4Cd0.6S and has a stronger visible light absorption compared to g-C3N4 and Ni0.8Co0.2/Zn0.4Cd0.6S in the range of 410 to 620 nm. The performance of the Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4nano-photocatalyst in the removal of methylene blue (MB)from an aqueous solution can be used as a basis for its proper performance for water splitting and H2 production too. Photocatalytic degradation of methylene blue in an aqueous solution was carried out under an LED lamp (100 W, 400-700 nm) illumination for 120 min. It was found that the degradation efficiency of methylene blue was 96% within this period. Thus, the Ni0.8Co0.2/Zn0.4Cd0.6S/g-C3N4nano-photocatalyst can act as a potential photocatalytic material for the degradation of pollutants and production of hydrogen under visible light.