Institute Center for Physical Sciences and Technology, Lithuania
Synthesis and advanced applications of TiOx based nanostructures
Since 2017 SimonasRamanavicius is a PhD student at State Research Institute Center for Physical Sciences and Technology, Lithuania. All his career as a researcher is devoted to the synthesis of various metal oxide based nanostructures and to finding application for those structures. As a researcher, Simonas has valuable experience and passion to share knowledge with other colleagues. He attended as a presenter at international conferences in the USA and Europe. As an active young scientist in 2019, he was nominated for the fellowship by Lithuania Research Council. Besides working in laboratory Simonas actively participates in Research and Research-Enterprise projects, where he applies his knowledge for nanotechnologybased solutions. The ongoing project is related to the development of metal oxidebased sensors for the determination of gases.
Statement of the Problem: Titanium dioxide (TiO2) is a very versatile material, which has a wide range of practical applications. It can be used in the design of sensors, biosensors, solar cells, waste water treatment systems, etc.Titanium oxide application areas especially depend on phase and crystal structure composition, surface morphology, band gap. Due to this fact, there is a high interest in the synthesis of new titanium oxide structures with new properties in order to extend its application. Thus, there is a high demand for a simple and efficient method for the production of new titanium oxide based materials with a desirable and easily controllable properties [1,2]. One of the ways to change TiO2characteristics is based on the formation of defective structures of titanium oxide (TiOx, where x<2).
Methodology & Theoretical Orientation:
In this work, hydrothermal synthesis was applied for the formation of nonstoichiometric TiOx with easily controllable characteristics.In order to prove the formation of TiOx, electron paramagnetic resonance (EPR) and X-ray diffraction (XRD) analysis methods were employed. Ellipsometry was used to measure the thickness and band gaps of the films.
Band gaps of synthesized structures varies from less than 3,2 eV to 1,29 eV depending on the oxide composition. The modelling was used for calculations the porosity of layers showing that porosity is nearly 80%, which could be very important for the application of these products in the gas sensing.
Conclusion & Significance:
In this research, nonstoichiometric TiOx thin films and nanoparticles were formed. Synthesized structures had exclusive characteristics such as high porosity and narrow bandgap. The narrow band gap is a great advantage due to the fact, that some characteristics of TiO2 noticed under UV light can occur in visible light illumination of TiOx structures.
Universidad de La Laguna, Spain
Magnetic nanoparticles and Nanoscale Metal-Organic Frameworks: advanced sorbents for sample treatment in determining small molecules of environmental interest
The collaborative behavior exhibited by the combination of Magnetic Metal-Organic Frameworks (MMOFs), containing a core of magnetite and shell of MOFs is related to the magnetic properties of nanomagnetite and the contribution from MOFs. Nano MOFs properties combines interesting properties for many applications in sample treatment such as high BET surface area, tunable pore size, and ratio pore to volume. Nano MOFs as sorbents for dispersive solid phase extraction of small molecules in sample posses several interesting attributes, such as high cargo loading capacity, ease of post-modification, tunable size and shape. Magnetic nano Fe-BTC was synthesized, the MMOFs was formed by a core of nanomagnetite and shell of Iron(III) metal–trimesic acid (BTC). Techniques such as scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy, were used to characterize the MMOFs sorbent. The new material was tested and applied as sobrbent for magnetic dispersive solid-phase extraction (DSPE) of small molecules related to pharmaceuticals uses such as fibrates (bezafibrate, clofibric acid, clofibrate, gemfibrozil, and fenofibrate) and dyes from triarylmethanes family from different type of water samples. Magnetic nano MOFS as sorbents present interesting properties, such as high loading capacity and selectivity for the tested small molecules making MMOFs excellent candidates as sorbents for determination of small molecules of environmental interest.
Acknowledgements This work has received financial support from MINECO (Spain) through projects Ref. MAT2014-57465-R and MAT2017-89207-R.
MIIT, Universiti Kuala Lumpur (UniKL), Malaysia
Ternary Flip-Flop based on Carbon Nanotube Field Effect Transistor
Dr. Soheli Farhana has completed her PhD in engineering from International Islamic University Malaysia and postdoctoral fellowship from International Islamic University Malaysia, Malaysia. She was the visiting researcher at ONE Lab, MIT, MA, USA. She has published several articles in reputed journals and has been serving as an editorial board member of reputed journals. Dr. Farhana is also serving as the committee member in several conferences. She is the reviewer of IEEE Transaction on Power Electronics and some relevant journal in Springer publication. Currently, Dr. Farhana is working as a visiting research professor at MIIT, UniKL, Kuala Lumpur, Malaysia. Her current research interests include Nanostructure materials, Nano-Electronics, Electrochemical properties of nanostructure and Nano Biosensor.
The scaling of current CMOS technology to nanoscale range leads to various critical challenges and reliability issues which will considerably reduce the potential of CMOS technology for high performance applications in near future. To handle these issues, such as electron tunneling through short channels and thin insulator films, variations in device structure and doping, increased leakage currents and high power dissipation towards new alternatives to replace bulk CMOS technology. Carbon nano tube field effect transistor (CNTFET) could be one promising and superior alternative, due to its resemblance with MOSFET in terms of intrinsic attributes and also due to its various superior characteristic. In CNTFET, the carrier velocity is almost double due to high mobility on account of ballistic transport operation with 1-D band structure than that of MOSFET.
This work shows a potential design of ternary circuits based on carbon nanotube transistors (CNTFETs) technology. Ternary logic is a promising alternative to the design of binary logic circuits; so it is possible to obtain simplicity and energy efficiency in the digital circuits design, namely, interconnections and chip area. Two types of ternary synchronous and asynchronous Flip-Flop is designed based on CNTFETs, which can be extended to the desired bits using the proposed Flip-Flop. Simulation results using SPICE CNTFET model demonstrate that the proposed ternary circuits consume significantly lower power and delay are 0.26µW and 177.7pS. Therefore, the reported results show that the presented CNTFET based ternary Flip-Flop design achieved great improvement in term of speed and power. Flip-Flip is used extensively as basic storage element in all kinds of digital systems.
Michigan State University, USA
Synergistic effect of post-deformation annealing on the micro-mechanical behavior of Zn-Mg hybrids processed by High-Pressure Torsion
Boehlert’s research interests include materials engineering; materials sciences; metallurgy; electron backscatter diffraction; intermetallics electron microscopy; metal matrix composites; titanium alloys and composites; mechanical behavior. His research group is concentrating on understanding the deformation behavior of hexagonal close packed metals, in particular, titanium zinc, and magnesium alloys, for a range of applications including the biomedical industry.
Heterostructured metals have attracted increasing interest because of their unique capability to overcome the strength-ductility trade off typically observed in engineering materials. Here, a new strategy for synthesizing heterostructured Zn-Mg hybrids is proposed via high-pressure torsion (HPT) followed by post-deformation annealing (PDA). Experimental results indicate a transition from a relatively homogenous nanograined structure after HPT, to a heterogeneous microstructure consisting of a bimodal grain size distribution with Mg2Zn11 and MgZn2intermetallic nanoprecipitates upon subsequent PDA. This led to a simultaneous increase in hardness and strain rate sensitivity. Close inspection of the strain hardening capability revealed that Zn-Mg HPT-processed hybrids followed a three regime behavior during plastic deformation. This mechanical response is suggested due to the activation of multiple strengthening mechanisms, including grain refinement, in-situ precipitation, and back-stress strengthening associated to geometrically necessary dislocations. Overall, the observed correlation suggests that the thermo mechanical processing can be tailored to obtain the desired hardening response across a HPT sample. This knowledge is expected to be transferable to other metal hybrid systems, thereby providing a means to design microstructures suitable for task-specific applications. Some of the targeted applications for this nanotechnology are biodegradable stents and implants.
Daura Refinery, Iraq
Supercritical Fluids as Reaction Media for Scalable Production of Carbon Nanomaterials
We have demonstrated scalable and selective synthesis of carbon nanotubes (CNTs), carbon nanofibers (CNFs), and onion-like carbons (OLCs) in a batch reactor using supercritical fluids (SCFs) as reaction media. The process utilizes toluene and alcohols (ethanol, propanol, and butanol) as carbon precursors in combination with ferrocene. Growth with supercritical toluene at 600 °C in the absence of water yields large diameter CNTs while introduction of 92.5 mmol/L of water enhances product yield by 50%, promoting formation of smaller diameter CNTs and decorating the exterior surface of CNTs with Fe nanoparticles. At 400 and 500 °C, in the absence of water, supercritical toluene produces mainly OLCs and CNFs, respectively. For alcohols, a gradual evolution of the morphology of nanocarbons forms from mainly OLCs to tube-like structures as the ratio of C/O atoms increases, possibly due to a decrease in the tendency of graphitic sheets to minimize their energies by curling into onion-like structures as chain length increases. This study provides a framework for utilizing SCF reaction media in a batch reactor to achieve scalable and selective growth of different nanocarbons and nanocarbon–metal nanocomposites
University of South Africa, South Africa
Synthesis, Functionalization, and characterization of Mesoporous silica nanoparticles for targeted Curcumin Delivery to Cancer Cells
In the fight against cancer, development of multifunctional drug carriers that can encapsulate, transport, and specifically release the drugs to cancer cells in an active and stimuli-responsive way is very important. In this study, mesoporous silica nanoparticles were successfully synthesized, functionalized with alginate and chitosan and bonded with folic acid. Curcumin loading, in-vitro drug release in phosphate buffered saline and acetate buffers, in vitro cytotoxicity assay, intracellular uptake and drug internalization by living cells were investigated. The as synthesized MSN particles were highly monodisperse with a hydrodynamic diameter of 639.9 nm. Layer-by-layer coating of MSN by polyelectrolytes and conjugation of folic acid were confirmed by TGA and the zeta potentials. High drug encapsulation efficiency and loading capacity of 53% and 2.3% were achieved at pH 5.5. In-vitro drug release confirmed absence of curcumin release at blood pH of 7.4 while an initial burst release was observed at acidic pH followed by a sustained curcumin release over 36 hours. MTT assay showed the biocompatibility of the drug carrier while confocal laser scanning microscopy confirmed the hyper uptake and internalization of the multifunctional drug carrier. Exposure of free curcumin, drug-loaded carrier with and without folic acid, to the surface of HeLa cells before and after folic acid blocking, showed the efficient folic acid receptor assisted drug internalization by the tumour cells. The investigation offered a route to fabrication of biocompatible, pH-responsive, tumour-specific drug carriers with sustained drug delivery. Further investigations of the in-vivo tumour efficacy of the developed carrier are underway.
The effect of Nano Graphene on the milling Process of Nano Composite
This paper studies the different content of Nano Graphene Oxide in to fracture properties (stress intensity factors and energy release rates)of nanocomposites of thermosetting polymer EPON 862 and its nano-graphene reinforced counterparts. Extremely low (0.2 and 0.3) weight percent Nano-graphene specimens were dispersed in EPON 862 matrix. Tensile tests were conducted under universal testing machine and using displacement control significant enhancement in fracture toughness and energy was about 23% and 22 % respectively and also the content more than 0.15 wt% (Weight percent ) had defection in to the desired mechanical results . in order to visualize and understand the mechanism of crack and fracture and energy and enhance these behavior result of Electron Microscopy (SEM) have been used and studied . Evidence of crack deflection due to increased surface roughness, NGO specimens pullout and plastic deformation of the matrix causing filler-matrix debonding, was observed. And also the effect of machining process and damage over this process and the role of machining and hole over the micro cracks using SEM analyzed and results discussed in this paper .
Ben-Gurion University of the Negev, Israel
The Role of Membrane Technology in Sustainable Wastewater
Gideon completed his graduate studies in the Technion-Israel Institute of technology. After completing his studies he went for a post doc position. After completing his post doc he joined Ben-Gurion University of the Negev. He worked on water issued in dry regions in the Blaustein Institute for Desert research. Currently he moved gradually form irrigation to water quality problems, which led him to nanotechnology. Current research deals with modeling of water systems combined with nanotechnology, optimization and application of operation research methods.
There is a growing need for extra waters in water-stressed areas including most countries in the Mediterranean Basin and the semiarid southwestern United States and Africa. The effect of effluent quality and the operating parameters such as transmembrane pressure, retardate and recirculation flow rates and fouling (clogging) aspects on productivity of a membrane system are discussed. This work is based on relatively large field experiment consisting of an hybrid nanotechnology system, at an area of about 0.6 hectares and lasted close to five years. Different crops were raised every year in same plots of abbot 200 m2. The effects of water quality, expressed mainly by the Electrical Conductivity (EC) and some relevant biological parameters of the effluent were monitored. Clogging of the membrane system was monitored as well. A preliminary economic analysis was conducted, examining the effects of water energy consumption due to fouling and the costs affecting the efficiency of the effluent applied for irrigation.
A nanotechnology system consisted of hollow fiber membrane was in operation. In front of the Reverse Osmosis (RO) system another component of Ultrafiltration (UF) was installed. The effluent outcome of the UF system was the feed for the RO system. It allowed removing both the pathogens and the suspended matter at the UF stage and the dissolved solids (salts) at the RO components. Different combination of UF and RO effluent were used for irrigating different crops each season. Different methods and policies were examined just to keep the membranes clean, and to allow a smooth performance.
Nanotechnology application to wastewater experiment was conducted under field conditions. Results indicate the options of salt removal and the effects on yields. No doubt that further experiments are required to verify the contributive effects of salts removal.
Aalto University, Finland
Enhancing the performance of all-copper redox flow batteries by ion exchange membranes
Cristina Flox currently works at Aalto University, developing new materials for Redox Flow Batteries (RFB), especially, copper-based electrolytes. She research is focused in the designing of nanomaterials for electrodes, new electrolytes formulations as well as innovative tools for predicting the ageing (i.e. failure mode) of RFB batteries. Her expertise is in the field of energy storage devices like supercapactiors, solid-state lithium-ion batteries, CO2 reduction and semisolid flow batteries.
Stationary energy storage systems have increased in relevance over the past decade because of their important role in grid-scale applications, enabling the integration of intermittent renewable energy (wind and solar); smart-grid integration (decentralized electricity), and electrical supply in remote areas. Redox flow batteries have become an effective solution and promising candidate due to their flexibility design (decoupled of energy and power); high efficiency and long cycle life. Due to their outstanding features, the state of the art contains a large variety of chemistries. For instance, the most developed and commercially available system is all-vanadium due to the low cross-contamination between both compartments, leading to excellent long-term stability. Nevertheless, the practical implementation of this mature technology has been hampered due to their high-cost of vanadium-based electrolytes, proving to be a critical factor for the widespread commercialization.
In this framework, copper redox flow batteries provide an attractive solution since its reduced cost (USD$ 7.4 Kg-1) in comparison with vanadium (USD$ 23.5 Kg-1). Moreover, copper is a non-toxic and an abundant metal with annual production capacity of up to 20 million tones. Another important feature is the high solubility of the copper in water (up to 3M), leading to energy density values comparable to vanadium redox flow batteries. In spite of aforementioned merits, the technology present several drawbacks. In particular, their performance above 20 mAcm-2 decline in terms of the cell capacity and energy efficiency due to the permeation of copper (II) species from the positive to negative side. In order to overcome this problem, the study of several membranes with outstanding selectivity features will be presented. Finally, the state of-the-art of the technology will be discussed in terms of economic and technological point of view, demonstrating their feasibility towards a real energy-storage solution.
Tarbiat Modares University, Iran
Characterization of high performance rubber composites
Gholamhossein Liaghat holds a PhD, and MSc from the UMIST Manchester, UK and BSc from Shiraz University in Mechanical Engineering. Before joining to Kingston University as visiting professor in 2012, he has been working for Tarbiat Modares University, Tehran, Iran (1990-present). He acts as Postgraduate Research Director (PGRC), and Head of the Applied Mechanics Engineering group. He had taught in UG and PG programs in School of Mechanical Engineering since 1990. He directed more than 115 MSc and 30 PhD projects and so far he completed supervision of 25 PhDs. His work experience includes a professorship at Tarbiat Modares University, as well as several visiting professor appointments at Kingston University. He has led a number of research projects in the area of Impact mechanics and High speed metal forming. He contributed about 114 papers and 4 books to the open press.
This study aims to investigate the static and high strain rate behavior of a rubber panel reinforced with fillers. To achieve a rubber compound with desirable properties, several ingredients are added to natural Rubber. Variation in compound ingredients alters the mechanical properties of rubber panels. One of the most important ingredient in rubber compound is the reinforcement. Carbon black is a common filler which act as a reinforcement and added to rubber formulations to improve mechanical properties. Rubber and the reinforcing filler(s), develop strong interactions that lead to the development of a structured material. To investigate the effect of compound ingredients specially the reinforcement, two types of rubber panel have been prepared and the behavior of rubber under static and high strain rates loads have been evaluated. It was found that deformation characteristics of the rubber are highly strain rate sensitive. It was concluded that the usage of carbon black results in a markedly higher energy absorption capacity in a variety of strain rates. The higher energy absorption was observed in higher loading of carbon black. The results are presented, discussed and commented upon.
Universidad del Valle, Colombia
Evaluation of human-structure-damper interaction in a grandstand
Modern civil structures are often prone to human induced vibrations. In particular, sport venues are subject to anthropic loads that can produce excessive vibrations and compromise structural service ability. The effectiveness of passive control systems for the reduction of vibrations in these structures is limited as the dynamic properties of the structure change due to crowd loads and human-structure interaction effects. Hence, a semi-active system is proposed for reducing human induced vibrations. This paper describes the implementation of a Pressurized Tuned Liquid Column Damper with a semi-active control (SA-PTLCD) strategy on a grandstand-type steel structure. The structure has a mass of 1000 kg while that of the PTLCD is 27 kg. The structure was excited both with sine sweeps using an electromagnetic shaker that has an active mass of 1.3% the mass of the structure, and with the coordinated jumping of upto five people with a total mass of 34% of that of the structure. Overall, the smart device had an exceptional performance for the different excitations and occupancy levels considered. For the case of five people jumping at the natural frequency of the structure, the SA-PTLCD reduced the peak acceleration to 41% of that of the structure without the control system.
Universidad del Valle, Colombia
Experimental evaluation of unbonded carbon and polyester fiber reinforced elastomeric seismic isolators
The base isolation system is one of the most used technologies implemented around the world to protect human lives and reduce damage of buildings during earthquakes. However, this system is rarely used in developing countries, such as Colombia, due to their high costs. The development of isolation bearings with local technology eliminates importation costs of these devices, which is the principal obstacle for its massive implementation in Colombia. This paper presents the experimental evaluation of low-cost seismic isolators for low-rise buildings, which represents over 70% of the construction projects in Colombia. Two types of high damping rubber matrix unbonded isolators without lead core were studied. Two different fibers were employed for the reinforcement of the bearings, carbon and polyester. Reduced-scale prototypes were manufactured and tested under simultaneous compression and shear loads, according to FEMA450 specifications. Results show similarity between vertical and horizontal stiffness and damping for the two isolators, both satisfying the minimum design values required. Finally, taking into account that the price of the polyester fiber is five times less than the carbon one, this is the alternative with higher potential to be implemented as a low-cost seismic isolation system in Colombia.
Non-toxic fluorescent silica Nanoparticles for observation of the living cell
Herein we report a novel synthesis yielding monodisperse fluorescent silica nanoparticles (SiNPs), with Fluorescein or Rhodamine-B incorporated within the core. Our nanoparticles are characterized by excellent photo-bleaching resistance. Illuminationwith a monochromatic laser light (wavelength λ=561 nm and power=38 mW), via continuous wave method, of a nanoparticle sample causes the loss of only 33% of the nanoparticles’ fluorescence intensity during 60 hours of illumination. This result is particularly important in bioimaging techniques, resulting in higher stability times and the possibility of use of lower SiNPs concentrations when performing measurements.
Moreover, our nanoparticles are non-toxic and highly biocompatible. A decline in cell vitality was not observed when Hela cells were incubated with PEG-coated silica nanoparticles containing Rhodamine-B. Nanoparticles were uptaken and remained in cells during following generations. Cells maintained high viability and proliferation potential for at least 14 generations after exposure. Due to their low cytotoxicity our PEG-coated silica nanoparticles are suitable for use in living cells and microorganisms.
Good solubility in aqueous environments is another important advantage of the presented nanomaterial. The described nanoparticles are characterized by prolonged stability, which exceeds 6 months at room temperature in aqueous solutions. The lack of toxic, commonly used stabilizers, such as azides, is especially beneficial in case of biological, biochemical and medical research.
These qualities of the nanoparticles make them potentially suitable for various biological and medical applications.
Fig. 1. Wide-field phase contrast and epifluorescence microscope pictures of
Masaryk University, Czech Republic
Interaction of Black Phosphorus (phosphorene) with smallmolecules and peptidesin MALDI TOF MS
Mr. Govinda Mandal, a resident of Mahottari, Nepal,graduated his B. Sc. in Microbiology from Tribhuvan University, Nepal and M. Sc. in Pharmaceutical Chemistry from HNB Garhwal University, India. He has more than 8 years of experience in Pharmaceutical Industries. He worked from basic analyst to higher Quality Management level (QC Manager, HOD). Presently, he is studying his PhD at Department of Chemistry, Faculty of Science, Masaryk University, A14/326-Kamenice 753/5, 625 00 Brno, Czech Republic.
Statement of the Problem:Black phosphorus (BP) represents the most stable allotrope (Fig. 1)withunique physico-chemical properties and with highnumber of bio-medical applications1.We have shown previously that phosphorusis an effective calibrant for MS analysis of complex biological samples2. In MALDI TOF MS, the BP selectively increases the ionization of some peptides3, 4. This phenomenon is not sufficiently explained so far. Here we address the mechanism of such altered ionization by combining BP and model peptide mixtures or relevant low mass molecules, such ascis-platinum and/or ruthenium complex ([RuClCp(mPTA)2](OSO2CF3)2).
Methodology & Theoretical Orientation:UV-Visible spectra were measured using UVmini-1240 Spectrophotometer, Shimadzu.Mass spectra were recorded (5 Hz frequency, pulsed width 3 nanoseconds) usingAXIMA CFR (nitrogen laser 337 nm, reflector), Kratos Analytical Ltd. The laser energy was selected from 0 to 180 a.u. (arbitrary units).Analyses were carried out in linear/reflectron positive/negative ion modes.
Findings:We studied adsorption of small peptidesand other low mass molecules like cis-platinum or Ru-complexon BP or on its single layer i.e. phosphorene (an analogue of graphene) surface.We found that BP interacts with different molecular moieties and affects the desorption energy. We propose, that such molecular interactions may be useful for more specific ionization and selective enrichment of the mass spectra with otherwise hardly ionizable molecular species. BP-
mediatedcommon MALDI matrices are promising materials for MS-based biotyping applications, ranging from metabolomics discrimination to complex bio-industrial scenarios, such as cell culture quality control5.
In summary, selective interactions of BP alter the ionization of peptides and other low mass molecules, and these phenomena may allow for more sensitive/selective MS detection. The BP-mediatedchanges depend on molecular structure of the partner compound, e.g. on number of aromatic rings or degree of saturation, areresulting in altered ionization in MALDI TOF MS.
Fig. 1: Structures of some phosphorus allotropes
Donghua University, China
Improving permeability, stability, and compatibility in the chemo-sensor and applied in bio-imaging
Octavinyl-polyhedral oligomeric silsesquioxane (OV-POSS) with amine-containing poly acryl amide (OV-POSS co-poly (acryl amide)) give a new fluorescent polymeric chemo sensor with fully water solubility. It shows better selectivity for Fe3+ in water solution over a wide detection range (pH=4-10). The incorporation of Fe 3+ to OV-POSS co-poly (acryl amide) results in a significant with fluorescence enhancement in water solution over other metal ions. Moreover, it was found that the system possesses low-cytotoxic, good permeability, high stability, and compatibility. Hence, it can be applied in bio-image successfully with bright blue fluorescent. Additionally, visible color change to the naked-eye from colorless to bright yellow can be observed directly when Fe3+ was added into chemo-sensor OV-POSS co-poly (acryl amide) compared with other metal ions.
Gediminas Technical University, Lithuania
Ultra-small methionine-capped Au0/Au+ nanoparticles as efficient drug against most dangerous bacteria
Mr. Rokas Zalneravicius received his B degree in Bioengineering at Vilnius Gediminas technical university in 2013 and Magna cum laude M degree in Chemistry of nanomaterials at Vilnius university in 2015. In 2017, he received Theodor Grotthuss memorial stipend for the academic achievement. He is currently pursuing his PhD degree at the Center for physical sciences and technology, Department of electrochemical material sciences, Laboratory of nanostructures in Vilnius, Lithuania. His research interest include antimicrobial surfaces and materials, catalysis, nanomaterials and 2D nano-composites for sensing applications.
It is commonly accepted that contrary to silver, gold in the metallic state is highly stable, biocompatible, and not cytotoxic even in the nanoparticulated size. Au nanoparticle antimicrobials render the grafted drug molecules, such as ampicillin, peptides or zwitterionic ligands. On the other hand, antimicrobial behavior of gold ions is well-known, has been widely investigated, and well-reviewed in Djuran and Glišic papers. According to the some recent reports, Au0 NPs reduced down to the nanocluster size, e.g. ≤2.0?nm in diameter, may also exhibit the antimicrobial activity against some fungi and bacteria strains. For example, Zheng et al. synthesized and tested 6-nm sized Au0 NPs and ≤2.0-sized gold nanoclusters both templated and protected with the 6-mercaptohexanoic acid. Although these NPs possessed quite similar surface zeta-potential, a remarkable antimicrobial efficacy has been established just for nanoclusters against S. aureus and E. coli killing roughly from 95 to 96 % of their population. Besides, it was concluded that the antimicrobial effect is not derived from the surface ligand and its content. On the contrary, Zhang et al. reported that cationic ligands of gold NPs contributed to their antimicrobial activity. This effect has been attributed to the strong ionic interaction with the bacteria indicating that positively charged ligand molecules of Au NPs are responsible for the bacteria membrane permeability increase.
Inspired by these works, in this study, we synthesized and tested ultra-small gold and gold-functionalized magnetite NPs comprised of Au0/Au+ for possible inactivation of multi-drug resistant bacteria. To the best of our knowledge, the antimicrobial behavior of ultra-small gold NPs stabilized with the amino acid has not been investigated against the most dangerous microorganism such as methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, and Salmonella enterica. For comparison, the antimicrobial efficacy of the magnetite NPs decorated with Au0/Au+ species were also tested.
Jay Robert Laceda
Polytechnic University of the Philippines, Philippines
Synthesis of nanocomposite based on impregnated bimetallic nanoparticles on activated carbon for adsorption of cadmium(ii) in aqueous solution
In this study , bimetallic Copper-Nickel nanoparticles impregnated on activated carbon (CuNiAC)nanocomposites was synthesized using sodium citrate as reducing agent and Poly(vinyl) alchohol as stabilizer. It was characterized using Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The synthesized CuNiACnanocomposites has the size range of 21-71 nm of impregnated nanoparticles and was used as the adsorbent for removal of Cadmium (II) in aqueous solution. The adsorption of Cadmium (II) in aqueous solution using CuNiACnanocomposites and commercial activated carbon was carried out so as to comparatively evaluate the effectiveness of both adsorbent for the purpose of removing Cadmium (II) from aqueous solution. The adsorption experiment performed indicated the suitability of using the synthesized CuNiACnanocomposites compared to the commercial activated carbon (AC) having the maximum percentage removal of 49.75 % in its highest dosage compared to the 21.57% removal percentage obtained by AC’s highest dosage. In terms of contact time the CuNiAC has the highest removal percentage which is about 13. 35% compared to 11.0 % removal percentage obtained by AC. This improved removal percentage of R20CuNiAC can be associated with the presence of additional adsorption sites provided by nanoparticles and presence of other functional groups on CuNiACnanocomposites as detected by Fourier transform infrared spectroscopy.
State Research Institute Center for Physical Sciences and Technology, Lithuania
Functionalization of iron oxide-based magnetic nanoparticles with gold shells
PhD student Agn? Mikalauskait? graduated from the Master of Science in Nanomaterial Chemistry and started Ph.D. in Chemistry in direction 03. During this period, the results of the master’s studies and doctoral studies were summarized and published in 5 scientific publications in Web-of-sci magazines with a citation index. Average index of quoted articles > 2.0. Also, the results of the last 3 years of research work have been presented at 9 international conferences, of which 5 orals in France, Germany, Lithuania and 4 stands in Lithuania. Scientific qualification upgrading in international schools related to the doctoral program: Portugal, VII Hands-on Course in Sample Preparation Using Nanoparticles for Proteomics. June 27-29, 2017 (4 days), BASF Summer School in Germany, 133rd International Summer Course August 21-26, 2017 Duration (week) and 1-month internship in Italy, Modena, Modena University of Reggio Emilia, Faculty of Physics and Nanosciences, Prof. The Marco Affronte Laboratory, which has been trained to characterize the objects of research, equipment for the detection of highly qualified magnetic properties.
This chapter is aimed at reviewing the methods reported to date for covering of magnetic iron oxide-based nanoparticles (NPs) with gold species and shells have found numerous applications in the recent nanomedicine as biocompatible materials for magneto hyperthermia, photothermal therapy, fluorescent and computed tomography imaging. Furthermore, through coating of magnetic NPs with gold their chemical and colloidal stability can be significantly improved allowing constructing a versatile platform for further NPs functionalization with antibodies, drugs, aptamers, and fluorescent agents.
Various studies have established the fact that a direct coating of magnetic NPs via electroless deposition using typical reducers such as sodium borohydride or citric acid is frequently problematic due to formation of gold crystallites in the solution bulk. To overcome this drawback, several methods for deposition of gold directly or through the intermediate layer onto the surface of magnetic NPs have been proposed during past 15 years. However, the reported approaches are mainly devoted to covering of magnetite (Fe3O4) and hematite (?-Fe2O3). Therefore, our recent findings dealt with these and other iron oxide-based, e.g. cobalt ferrite, NPs are presented in more detail. Contrary to the previous works reported the formation of continuous Au0 nanoparticulate shells, we succeed in the decoration of magnetic NPs with numerous Au0/Au+ quantum dots (QDs) contributing to their prospective future applications. In addition to presentation of reported to date gold deposition techniques, an attempt was made to discuss shortly the possible application trends of these core-shelled NPs.
Recently, gold-shelled iron oxide-based NPs are widely used for biological treatments and medical investigations because of their super paramagnetic behavior, non toxicity, chemical stability in various fluids and biocompatibility as well as capability to interact with the specific ligands, such as proteins, antibodies, drugs, nucleic acids, etc. Taken together, uniformly sized gold-coated magnetic NPs possess a great potential for tumors detection, anticancer therapy, immunogenicity and analytical sensing. Besides, the attached gold due to collective oscillation of free electrons in a continuous band structure can demonstrate crystallite size dependent plasmonic resonance band sensitive to the microenvironment. As a matter of a collective magnetic and optical behavior, a variety of new applications of gold-coated magnetic NPs were reported during the past decade.
Figure 1. TEM images of the CoFe2O4@Au NPs (a) and gold products remaining after CoFe2O4@Au NPs etching in the HCl (1:1) solution for thinner (c) and thicker (d) shells. In (b) the SAED spectrum taken from the scope of gold-coated cobalt ferrite NPs.
University of Technology, Iran
First principle study of the magnetic properties of interstitial Co in graphene nanosheet
Mahmoud Jafari is an associate professor of physics at K. N. Toosi University of Technology. His PhD has been done in condensed matter physics at University of Picardy Jules Verne in France (1991). His research interests are in the area of material science, in particularly computational study of physical properties of nanomaterial and 2D materials such as carbon and graphene. In addition his interests work on fuel cell and biomaterial has been started.
The aim of the present study was to investigate the magnetic properties of interstitial Co in graphene nanosheet. The calculations have been performed in the framework of density functional theory and the GGA approximations within Quantum Espresso package. Our results show that the adding Co impurity, change the electronic and magnetic properties of this structure. The magnetic properties of this structure depend on the Co atom, which will be attained the magnetic metal or magnetic semiconductors. According to this calculation, the magnitude of the magnetic moment measured for Co impurity is 1.11 Bohr Magneton.
Universidade Federal de Santa Maria, Brazil
Poly (beta--caprolactone) nanoparticles with pH-responsive behavior improved the in vitro antitumor activity of methotrexate
Methotrexate (MTX, 2,4-diamino-N10-methyl-folic acid) is a cytotoxic drug with the competitive inhibition of dihydrofolate-reductase as pharmacological target. As this drug inhibits a key cellular function, its cytotoxic activity is not specific towards neoplastic cells and, consequently, the therapy often causes severe side effects. In this context, the conjugation of the active molecule to a nanostructured delivery system is a promising approach to achieve a more efficient antitumor therapy. Moreover, on account of pH differences between cancerous (~pHe 6.6 e 5.4) and healthy (pH 7.4) tissues, the design of pH-sensitive systems at micro/nano scale can be used to improve tumor-targeted drug delivery. Therefore, the main objective of this research was to prepare nanoparticles (NPs) based on the polymer poly (ε-caprolactone) (PCL) and with the nonionic surfactant poloxamer 407 as formulation stabilizer, as a carrier for the antitumor drug methotrexate. In addition, the biological properties of the proposed nanocarriers were evaluated using different in vitro cell models. The conjugation of the lysine-based amphiphile, 77KL, to the NP matrix was the approach used to reach a formulation responsive to pH variations. The NPs showed mean hydrodynamic diameter and drug entrapment efficiency of 178.5 nm and 20.52%, respectively. Improved formulation stability was achieved after lyophilization. Drug nanoencapsulation was also able to protect MTX from photodegradation induced by UVA and UVC radiation. The hemolysis assay was applied to study the pH-sensitive membrane-lytic activity and hemocompatibility of the NPs. The PCL-NPs appeared to be hemocompatibles and, owing to its pH-sensitivity, showed membrane-lytic behavior upon reducing the pH value of surrounding media to 5.4, which is characteristic of the endosomal compartments. Likewise, these pH-responsive NPs released MTX slightly faster at pH 5.4 than at physiological conditions. This NP feature might be a promising approach to achieve a greater and more specific drug release in cancer cells, thanks to its likely capacity to respond to the pH gradients existing in tumor tissue and intracellular compartments. The in vitro antitumor assays, using MTT and NRU as viability endpoints, demonstrated that MTX-loaded PCL-NPs have higher antiproliferative activity than free drug in MCF-7 cells and, to a lesser extent, in HepG2 cells. Noteworthy is that this same behavior was also markedly observed at mildly acidic conditions (pH 6.6), characteristic of the tumor microenvironment. Therefore, the overall results evidenced the pH-responsive properties of the designed nanocarrier, together with its greater in vitro cytotoxic activity compared to the non-associated drug, suggesting, thus, that this nano-based formulation could be promising for an innovative and more efficient antitumor therapy.
Acknowledgements: Capes-Print Financial code 001; CNPq for the Grant 401069/2014-1 and for the Postdoc fellowship.
Masaryk University, Czech Republic
Laser Ablation Synthesis (LAS) of Ge-Sb, Ge-Te and Sb-Teclusters
Mr. FeiHuang completed his bachelor's degree in 2011 and then he worked in an oil company for three years. He continued to pursue a master's degree and graduated in 2017 from Xi'an Shiyou University,Xi'an,China. Presently, he is PhD student at Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A14, 62500 Brno, Czech Republic.
Statement of the problem:Germanium-Antimony-Tellurium (GST) is one of the most important phase-change-memory material.The Ge2Sb2Te5 bulk material has been studied by using mass spectrometry in our laboratory an recent detailed review of this phase change non-volatile memories is available. Here, we deal with the binaries (Ge-Sb, Ge-Te, Sb-Te) forming the ternary GST system. Laser ablation synthesis (LAS) can efficiently generate clusters from the mixture of elements and simultaneous use of a Time-Of-Flight (TOF) mass spectrometer (MS)determines the clusters composition. The methodology has already been shown to be a powerful method to study the formation of various clusters from inorganic compounds, glasses and/or mixtures.
The aim of this work is to use mass spectrometry following in details the formation of the binary clusters during LASin order to cover wide concentration ranges and to contribute further to the knowledge of these materials.
Methodology & Theoretical Orientation:The formation of binary GemSbn, GemTeo, and SbnTeo clusters generated by LAS from binary Ge-Sb, Ge-Te, and Sb-Te mixtures of elements was studied and stoichiometry of clusters was determined (cf. Fig.1). Structure of individual clusters generated from a mixture of elements was discussed.
Findings: i) LASwas found as a suitable method to generate binary clusters of GST material components. ii) Via computer modeling complicated isotopic patterns of clusters can be resolved, iii) Composition of clusters might represent partial structural fragments of the phase-change material. The results enable to understand structural motifs of the GST materials and the findings obtained can contribute to the proposal of new, more efficient phase-change memory materials.
Fig.1 Scheme of MS analysis
Angel Jimenez Chavez
National Autonomous University of Mexico, Mexico
B19 parvovirus-like particles as a delivery system of neoepitopes to prime cellular immunity against triple negative breast cancer
Angel Jimenez is an experimental biologist who has specialized in the search for new treatments for cancer, showing a special interest in the relationship between the immune system and cancer. He is currently studying his doctorate at the National Autonomous University of Mexico, focuses on the production and characterization of parvovirus B19 virus-like particles assembled in cell-free environment as antigen delivery systems to dendritic cells in lymph nodes for personalized immunotherapies, using a murine model of triple negative breast cancer.
Statement of the Problem: Triple negative breast cancer (TNBC) continues to be a major health problem which lacks molecular targets for therapy. The neoepitopes may represent a viable option for the induction of antitumor immune responses in TNBC. When used in the form of peptides or RNA neoepitopes have shown to be capable of inducing immune responses associated with improved clinical responses, nevertheless, limitations such as low immunogenicity and induction of tolerance remain. Virus-like particles (VLPS) of parvovirus B19 may be used as an alternative antigen delivery system. In this work, we designed and evaluated the therapeutic effect of chimeric B19 VLPs with multiple neoepitopes of the 4T1 cell line in the 4T1-induced breast cancer model.Methodology: Balb/c mice of 6-8 weeks with breast tumors received 4 therapeutic immunizations with chimeric VLPs, native VLPs, vehicle, or VLPs plus adjuvant; and tumor growth, lung macro-metastasis and specific immune responses were evaluated. Findings: Our results showed that therapeutic administration of multi-epitope chimeric-VLPs with and without adjuvant were able to significantly delay the tumor growth with respect to the vehicle and the native VLPs, chimeric VLPs significantly decreased the number of macro-metastasis in the lung in mice immunized. The analysis of the cell populations showed a decrease of the MDSC in the groups co-administered with the adjuvant, moreover, specific responses of CD8 and CD4 T lymphocytes towards the neoepitopes were induced in inguinal node. Besides, these CD8 T lymphocytes were positive to the production of granzyme B. Our results show that the use of VLPs-B19 as a delivery system of neoepitopes can induce specific cellular responses able to impact tumor growth and lung macro-metastasis in vivo, so they could be a good option as delivery system for antigens in personalized immunotherapy.
Universidad de La Laguna, Spain
Surface Structure of Graphene Oxide: a tunable platform for removal of compounds of environmental interest
The chemically modified surface of graphene provides interesting opportunities for tuning adsorption properties. It is well-known the increasing concern about the vulnerability of water resources and water supplies worldwide, due to the presence pf organic and inorganic contaminants. Especially, with respect to so called, ermerging contaminants. In this study, materials derived from its surface chemical modification were characterized, tested for its capacity to remove and/or for adsorption of different kind of wastewater contaminants such as heavy metals, azodyes and pharmaceutical compounds (diclofenac, gemfibrozil, bezafibrate and clofibrate). The importance of temperature, pH, ionic strength, and ionic strength in uptaking of contaminats on the graphene oxide materials were studied. A discussion of possible interactions justifying the partitioning of analytes to the GO is included, considering not only the analytes’ physicochemical characteristics, aqueous environment, and chemical modification of the surface.
Universidad del Valle, Colombia
Experimental characterization of a seismic isolator prototype with recycled rubber for the mitigation of structures’ risk
During the past decades, in the field of civil engineering new techniques for the design of earthquake-resistant structures have developed; an example of this is seismic isolation, in which earthquake’s energy is absorbed through devices (seismic isolators), diminishing its impact on the structure and further damages. Nowadays, the commonly used devices for this purpose are the SREIs, Seismic Rubber Elastomeric Isolators, that due to their weight and composition, they have a high cost in countries where they are not fabricated or tested, limiting its implementation to large-scale and special-use projects. As a solution to this, the UFREIs, Unbounded Fiber Reinforced Elastomeric Isolators, have been developed, that given to their lightness, they can be used without being connected to the structure itself, which significantly reduces its cost. On the basis of the for egoing, considering that Colombia is not yet a producer of isolators, during this research, reduced-scale prototypes of UFREIs were developed; in which instead of using natural-based rubber for the matrix, recycled rubber derived from tires was used. The research was divided into four phases, in the first one, the process of extraction of the tire's rubber was defined. The second phase was a process of mechanic characterization of the rubber since there’s a wide diversity of it depending on the different producing brands in the market. Based on the results, the adequate model of tires for the construction of UFREIs was identified. The third phase consisted on the construction of the prototypes, defining the design of the mold and the constructive method. During the last phase, the prototypes were subjected to monotonic compression tests determining their mechanical properties. From the results, it was possible to verify that the vertical stiffness obtained is suitable for use in low-height residential projects, which, given the high volume of construction of these projects in Colombia, would guarantee a massive use of the developed devices, besides giving a solution to an environmental problem of the country.
Keltouma Ait Aissa
CNRS and Université d’Orléans, France
Doping effect of fluorine and chlorine ions implantation on structural and microstructural properties of 2-dimensional tungsten disulfide (WS2)
The remarkable research effort has become known as the transition to the metal of dichalcogenide (TMD). They include tungsten disulfide (WS2) and molybdenum disulfide (MoS2) both with lamellar structure. However, WS2 is thermally more stable and then presents a larger operating temperature range. WS2 also allows an adjustable band gap in 1.4-2.1 eV range. The band gap is both material structure and number of layers dependent. Pristine WS2 is p-type doping due to sulfur vacancies. To achieve electronic devices such as photodiode, n-type doping is fundamental. In this work we have studied structural, microstructural and morphological properties of tungsten disulfide (WS2) thin films before and after 100 keV F and 180 keV Cl2+ ion implantation with a fluence of 1014 ions in both cases. WS2 films were synthesized by vapor phase sulfurization of tungsten films on SiO2/Si substrates using thermal chemical vapor deposition (TCVD). After ion-implantation of WS2 films with Cl2+ and F ions, a new peak attributed to the effect of Cl2+ and F dopant was appeared around 172 cm-1 by Raman spectroscopy. In addition, the (002) peak for Cl2+ ion implantation and the (002) peak shift related F ions were confirmed by the XRD analysis. The microstructural analysis by TEM shows that presence the defect in the ws2 film after Cl2+ doping. This technique of implantation can be used to reduce the burden of WS2 film.
RMIT University, Australia., Australia
Metal-Organic-Frameworks as non-viral delivery vehicle for gene therapy in prostate cancer cells
Arpita Poddar has her expertise in the biological uses of metal-organic-frameworks and is passionate about their applications in cancer biology. Her PhD is focused on gene delivery, and she specializes in DNA encapsulation, storage, protection and cellular delivery using MOFs. The work of her thesis has resulted in the formulation of a viable, physiologically stable and facile non-viral gene delivery system with MOFs as alternatives to commercially available cationic lipids which simultaneously open novel avenues for cancer gene therapy.
Prostate Cancer (PC) is the second leading cause of cancer death in males. Due to anatomy of the organ and physiology of the disease, gene therapy for PC is extremely promising in preliminary clinical trials. However, intra-cellular delivery of genes for gene therapy is still at early stages and calls for additional technological breakthroughs to realise its full potential. Although viruses are powerful delivery systems (vectors), they raise important safety concerns which severely limit their applications in clinical settings. Non-viral vectors are safer, non-immunogenic, inexpensive, can carry large quantities of DNA and have easy modifications. However, current non-viral vectors have given conflicting results and, up to 2018, only 0.24% of research was carried out on non-viral vectors. The lack of proper non-viral systems is thus a critical aspect that needs to be addressed for successful gene therapy.
The work presented employs the use of metal-organic-frameworks (MOFs) as non-viral vectors for the delivery of genes to PC cells. MOFs are a new class of porous hybrid materials in nanotechnology composed of metal ions and organic bridging ligands. They are emerging as promising platforms for therapeutic delivery, bioimaging and biosensing due to their high drug loadings, biodegradability, and versatile functionality. The study investigates the synthesis of different kinds of MOFs that show minimal/no cellular toxicity and can be synthesized under non-toxic and physiological conditions. We show that ZIF-8 MOFs can successfully encapsulate not just short chain nucleic acids, but entire gene sets in a one pot synthesis step based on biomimetic mineralization to form DNA@ZIF-8 conjugates. The results signify the use of MOFs to deliver intact genes to PC cells in a non-cytotoxic manner with gradual release; characteristics which are essential for a suitable gene therapy delivery system.
Schematic representation of plasmid DNA genes (plGFP) encapsulated in ZIF-8 MOF
University of Cartagena, Colombia
Elimination of Cypermethrin using Fe-TiO2 nanoparticles supported on coconut palm spathe using a solar flat plate photoreactor
- High Fe+3 concentration generates TiO2 catalyst poisoning.
- Coating and doping of TiO2 impact negatively on its photocatalytic performance.
- Coating with nanoparticles allows to eliminate separation processes.
Cypermethrin (Class II, moderately dangerous) causes human health problems related to immunosuppression, hormonal alteration, diminished intelligence, reproductive anomalies and cancer. In the studies carried out in this area, only 0.1% of the pesticide used reaches the target pest and 99.9% is dispersed in the environment through routes such as runoff and erosion, leaching, drainage and discharges of pesticide production plants.
TiO2 nanoparticles were synthesized by the method of Green Chemistry assisted by ultrasound using aqueous extract of lemon grass (Cymbopogon citratus) and modified with Fe+3 atoms by means of Chemical Impregnation, while the immobilization of the nanoparticles on Coconut palm spathe was carried out through the Doctor Blade technique. The concentration of cypermethrin was determined after 12000 J/m2 of accumulated radiation from GC-MS, the powder materials was characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM) image and selected area electron diffraction (SAED), Raman spectroscopy, Cathodoluminescence, Photoluminescence, Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometry of diffuse reflectance and BET surface area, while composite materials (coconut palm spathe/catalyst) were analyzed through Scanning electron microscopy (SEM).
3. Results and discussion
The XRD pattern shows ten distinct peaks at 2θ = 25.61°, 37.8°, 38.10°, 48.47°, 54.24°, 55.36°, 62.99°, 69.20°, 70.59°, 75.47° in the XRD pattern of Fe3+ doped TiO2 and undoped nanopowders are consistent with anatase (101), (103), (004), (200), (105), (211), (204), (116), (220) and (107) lattice planes (JCPDS No. 21-1272).
The surface morphology and particle size (size distribution) of the pure (Fe:Ti=0) photocatalyst were further analyzed by TEM, it’s evident from these images that the synthesized nanoparticles were agglomerated, and their shapes were quasi-nanospheres. The optical properties of TiO2 and Fe-TiO2 were separately detected by ultraviolet- visible diffuse reflection spectrometer (UV–Vis DRS). The absorption edge of the Fe-TiO2 in comparison to undoped TiO2 is extended greatly toward the visible light. The absorption edge is more extended to the visible light with the increasing of the Fe concentration, which is induced by the electron transition from Fe3d orbitals to TiO2 conduction band (CB). In N2 physical adsorption-desorption study, it was observed that the prepared TiO2 and Fe-TiO2 possess mesoporous surface as the isotherms are of Type IV and with typical H3 hysteresis loop according to the IUPAC convention, it indicates that TiO2 sample contain non-rigid aggregates of plate-like or slit shaped pores with a contribution of micropores and mesopores.
Results obtained for the photocatalytic degradation of Cypermethrin using nanomaterials suspended and immobilized, as well as the respective soft adsorption and photolysis. The molar ratios higher than Fe:Ti (Fe:Ti=0.075 and Fe:Ti=0.1) and the immobilization of nanoparticles on the spathe of coconut palm biomaterial generate a decrease in the percentages of elimination.
The immobilization of nanoparticles on coconut palm-based biomaterial using the resin applied in this study brings two important advantages from an economic and environmental point of view.
Seyedeh Fatemeh Shamekhi
Tarbiat Modares University, Iran
Chitosan coated alginate nanoparticles for oral sustained delivery of liraglutide
Dr. Fatemeh Shamekhi has her expertise in encapsulation methods and optimization techniques of corating components for oral drug delivery. She had her specific focus on nanostructures and their characterization methods as well as their behavior through simulated gastrointestinal tract condition (in vitro models).
She has extensive experience in the academic field which extends to more than 10 years.She is currently a Lecturer at Azad University. She earned her Ph.D. degree in Nano-biotechnology from TarbiatModaresUniversity in 2018. Her master degree was in Enzyme Biotechnology from University Putra Malaysia. She published many peer-reviewed papers in Scopus indexed journals with impact factor as well as conference papers.
Chitosan coated calcium-alginate nanoparticles were developed for oral sustained delivery of liraglutide. The concentrations effect of coating constituents including sodium alginate, calcium chloride, and chitosan on the particle size was studied based on response surface methodology. The beads were characterized by dynamic light scattering (DLS), scanning and transmission electron microscopy (SEM, TEM) as well as Fourier transform infrared spectroscopy (FTIR). The diameter of the formed beads was most dependent on the coating technique and alginate concentration. The spherical particles of up to 100?nm diameter were developed for the optimum composition of alginate 0.5%, chitosan 0.5% and calcium chloride 0.5% in the volume ratio of 2:0.5:1. In- vitro release studies in simulated gastrointestinal conditions were carried out in a sequential technique and the amount of drug release was found to be 43.2% after 8?h. The MTT results on human intestinal cell line Caco-2 revealed more than 100% cell viability after 24 hours for blank nanoparticles and up to 68.05% viability enhancement compared to the free drug in 0.3 mg concentration. The results of this study demonstrated that chitosan coated alginate nanoparticles hold promise as a potential natural biodegradable polymer-based oral carrier of liraglutide for better management of diabetes.