Publications by Year: 2016

Zhou Y, Layani M, Boey FYC, Sokolov I, Magdassi S, Long Y. Electro-Thermochromic Devices Composed of Self-Assembled Transparent Electrodes and Hydrogels. Adv. Mater. Technol. (Weinheim, Ger.)Advanced Materials Technologies (Weinheim, Germany). 2016;1 (5) :n/a.
Kamyshny A, Magdassi S. Microencapsulation., in Encycl. Surf. Colloid Sci. (3rd Ed.). Vol 6. CRC Press ; 2016 :4636 - 4648.Abstract
Microencapsulation is a process by which a gas, liq., or solid material (core) is packaged inside capsules of a second material (shell), which protects and isolates the core material from the surrounding environment and adjusts its properties in accordance with requirements. In other words, a microcapsule (MC) is a reservoir contg. an active substance surrounded by a membrane (typically made of a natural or synthetic polymer). MCs are spherical or irregular particles in the size range from 50 nm to a few hundred micrometers; the most widely used are capsules of micron size (capsules smaller than I mm are often classified as nanocapsules, and capsules larger than 1000 mm are called macrocapsules or beads). Com. MCs typically have a diam. between 3 and 800 mm. In this entry we focus on the manufg. methodologies and mechanisms of microencapsulation, including evaluation of the nature and properties of core and shell ingredients. Current and potential applications of MCs in various fields of chem. and life sciences, as well as in related industries, will also be presented. [on SciFinder(R)]
Ke Y, Balin I, Wang N, Lu Q, Tok AIY, White TJ, Magdassi S, Abdulhalim I, Long Y. Two-Dimensional SiO2/VO2 Photonic Crystals with Statically Visible and Dynamically Infrared Modulated for Smart Window Deployment. ACS Appl. Mater. InterfacesACS Applied Materials & Interfaces. 2016;8 (48) :33112 - 33120.Abstract
Two-dimensional (2D) photonic structures, widely used for generating photonic band gaps (PBG) in a variety of materials, are for the 1st time integrated with the temp.-dependent phase change of VO2. VO2 possesses thermochromic properties, whose potential remains unrealized due to an undesirable yellow-brown color. A SiO2/VO2 core/shell 2D photonic crystal is demonstrated to exhibit static visible light tunability and dynamic near-IR (NIR) modulation. Three-dimensional (3D) finite difference time domain (FDTD) simulations predict that the transmittance can be tuned across the visible spectrum, while maintaining good solar regulation efficiency (ΔTsol = 11.0%) and high solar transmittance (Tlum = 49.6%). The color changes of VO2 films are accompanied by NIR modulation. This work presents a novel way to manipulate VO2 photonic structures to modulate light transmission as a function of wavelength at different temps. [on SciFinder(R)]
Halevi O, Jiang H, Kloc C, Magdassi S. Additive manufacturing of micrometric crystallization vessels and single crystals. Sci. Rep.Scientific Reports. 2016;6 :36786.Abstract
We present an all-additive manufg. method that is performed at mild conditions, for the formation of org. single crystals at specific locations, without any photolithog. prefabrication process. The method is composed of two steps; inkjet printing of a confinement frame, composed of a water sol. electrolyte. Then, an org. semiconductor soln. is printed within the confinement to form a nucleus at a specific location, followed by addnl. printing, which led to the growth of a single crystal. The specific geometry of the confinement enables control of the specific locations of the single crystals, while sepg. the nucleation and crystal growth processes. By this method, we printed single crystals of perylene, which are suitable for the formation of OFETs. Moreover, since this method is based on a simple and controllable wet deposition process, it enables formation of arrays of single crystals at specific locations, which is a prerequisite for mass prodn. of active org. elements on flexible substrates. [on SciFinder(R)]
Pajor-Swierzy A, Farraj Y, Kamyshny A, Magdassi S. Air stable copper-silver core-shell submicron particles: Synthesis and conductive ink formulation. Colloids Surf., AColloids and Surfaces, A: Physicochemical and Engineering Aspects. 2016 :Ahead of Print.Abstract
We report on the synthesis of copper-silver core-shell (Cu@Ag) particles with about 1 μm-diam. Cu core coated with a thin (∼20 nm) silver shell, for application in printed electronics as low cost conductive ink. The process is based on using the environmentally friendly sodium formaldehyde sulfoxylate dehydrate as a reducing agent for copper ions and two types of polymeric stabilizers (nonionic PVP and anionic PAA). The formation of core-shell particles is followed by transmetallation reaction on the surface of the Cu particles, where copper atoms function as the reducer for silver ions. Characterization of the submicron particles by SEM, EDS and XRD confirm the core-shell structure. The resulting Cu@Ag particles enable overcoming a major challenge in copper ink, their rapid oxidn. in air. It was found that ink formulations based on propylene glycol as the liq. vehicle and contg. a silicone based wetting agent possesses the optimal characteristics (wetting, sintering) for printing on a glass substrate. To obtain conductive metallic structures, thermal sintering of metallic patterns was used. The Cu@Ag coating are stable to oxidn. for at least 6 mo at room temp., and also during sintering process which is carried out at temps. up to 250 °C. The cond. of Cu@Ag coatings after sintering at 250 °C was high, 16% of that for bulk copper. [on SciFinder(R)]
Bera RK, Mhaisalkar SG, Mandler D, Magdassi S. Formation and performance of highly absorbing solar thermal coating based on carbon nanotubes and boehmite. Energy Convers. Manage.Energy Conversion and Management. 2016;120 :287 - 293.Abstract
A major component of solar thermal systems is the solar absorber, which converts light into heat. We report on achieving high absorptance, excellent adhesion, and high thermal stability of carbon nanotube-based black coatings by applying a layer of Boehmite (AlOOH) on top of the carbon nanotube (CNT) film by soln.-processed spray deposition. The CNT layer made-up by spraying, functions as an absorbing layer and the AlOOH serves as an anti-reflecting and protecting film. The anti-reflecting property of AlOOH layer effectively increases the absorptance of CNT coating by decreasing the reflectance. The effect of the thickness of AlOOH layer on the absorptance, adhesion, and thermal stability of the resulting CNT/AlOOH coating was investigated. The CNT/AlOOH coating with optimized thickness of AlOOH layer shows very high absorptance (α) of 0.975. The adhesion of the coating is in the range of 95-100% with significant increase of thermal stability. This new approach is expected to open new possibilities for fabricating low-cost, highly efficient and thermally stable solar-thermal devices which are based on simple coating processes. [on SciFinder(R)]
Misra RK, Aharon S, Layani M, Magdassi S, Etgar L. A mesoporous-planar hybrid architecture of methylammonium lead iodide perovskite based solar cells. J. Mater. Chem. AJournal of Materials Chemistry A: Materials for Energy and Sustainability. 2016 :Ahead of Print.Abstract
We report a hybrid mesoporous-planar architecture of methylammonium lead iodide perovskite based solar cells, to combine the benefits of both the mesoporous and planar architectures in a single device. A mesoporous-TiO2 grid was fabricated on a compact TiO2 layer, through a self-assembly process based on directional wetting, providing regions with and without mesoporous-TiO2, followed by perovskite deposition and back contact evapn. (hybrid cells). The hybrid cells showed up to 10.7% power conversion efficiency (PCE) as compared to 13.5% and 6.3% for their mesoporous and planar counterparts, resp. Interestingly, the hybrid cells are found to show a short circuit c.d. (Jsc) as high as the Jsc of the mesoporous TiO2 based cells and proved to conserve the c.d. even in the absence of mesoporous-TiO2 from planar parts of the hybrid cells. The cells showed the best fill factor as compared to their mesoporous and planar counterparts. The areal variation in the meso to planar ratio has also been realized by changing the grid size to demonstrate the effect of the architecture on the cell performance. Charge extn. measurements have been used to obtain insight into the recombination inside different solar cells architectures. The hybrid cell structure emerged as a novel promising design for perovskite solar cells. [on SciFinder(R)]
Lu Q, Liu C, Wang N, Magdassi S, Mandler D, Long Y. Periodic micro-patterned VO2 thermochromic films by mesh printing. J. Mater. Chem. CJournal of Materials Chemistry C: Materials for Optical and Electronic Devices. 2016 :Ahead of Print.Abstract
VO2 has garnered much attention in recent years as a promising candidate for thermochromic window applications due to rising awareness about energy conservation. However, the trade-off between improving the luminous transmittance (Tlum) and solar modulation ability (ΔTsol) limits the commercialization of VO2-based smart windows. Four major nanostructuring approaches were implemented to enhance both Tlum and ΔTsol, namely nanocomposites, nanoporous films, biomimetic moth-eye structures and anti-reflection coating (ARC) multilayers. This work demonstrates a novel approach that fabricates periodic, micro-patterned structures of VO2 using a facile screen printing method. The micro-patterned structure is able to favorably transmit visible light without sacrificing high near-IR modulation, and the patterned film shows improved Tlum (67% vs. 60%) and ΔTsol (8.8% vs. 6.9%) compared with continuous films. By varying the thickness, periodicity and solid concn., this approach can give a ΔTsol of 14.9% combined with a Tlum of 43.3%, which is comparable, if not superior to, some of the best reported results found using other approaches. [on SciFinder(R)]
Portnoy E, Polyak B, Inbar D, Ben-Hur T, Ekstein D, Kenan G, Rai A, Wehrli SL, Roberts TPL, Bishara A, et al. Tracking inflammation in the epileptic rat brain by bi-functional fluorescent and magnetic nanoparticles. NanomedicineNanomedicine : nanotechnology, biology, and medicine. 2016;12 (5) :1335 - 45.Abstract
Correct localization of epileptic foci can improve surgical outcome in patients with drug-resistant seizures. Our aim was to demonstrate that systemically injected nanoparticles identify activated immune cells, which have been reported to accumulate in epileptogenic brain tissue. Fluorescent and magnetite-labeled nanoparticles were injected intravenously to rats with lithium-pilocarpine-induced chronic epilepsy. Cerebral uptake was studied ex vivo by confocal microscopy and MRI. Cellular uptake and biological effects were characterized in vitro in murine monocytes and microglia cell lines. Microscopy confirmed that the nanoparticles selectively accumulate within myeloid cells in the hippocampus, in association with inflammation. The nanoparticle signal was also detectable by MRI. The in vitro studies demonstrate rapid nanoparticle uptake and good cellular tolerability. We show that nanoparticles can target myeloid cells in epileptogenic brain tissue. This system can contribute to pre-surgical and intra-surgical localization of epileptic foci, and assist in detecting immune system involvement in epilepsy.[on SciFinder (R)]
Zarek M, Layani M, Cooperstein I, Sachyani E, Cohn D, Magdassi S. 3D Printing of Shape Memory Polymers for Flexible Electronic Devices. Adv. Mater. (Weinheim, Ger.)Advanced Materials (Weinheim, Germany). 2016;28 (22) :4449 - 4454.Abstract
The authors describe a general and facile method based on 3D printing methacrylated macromonomers to fabricate shape memory objects that can be used in flexible and responsive elec. circuits. Such responsive objects can be used in fabrication of soft robotics, minimal invasive medical devices, sensors, and wearable electronics. The use of 3D printing overcomes the poor processing characteristics of thermosets and enables complex geometries that are not easily accessible by other techniques. [on SciFinder(R)]
Pawar AA, Saada G, Cooperstein I, Larush L, Magdassi S, Jackman JA, Tabaei SR, Cho N-J. High-performance 3D printing of hydrogels by water-dispersible photoinitiator nanoparticles. Sci AdvScience advances. 2016;2 (4) :e1501381.Abstract
In the absence of water-soluble photoinitiators with high absorbance in the ultraviolet (UV)-visible range, rapid three-dimensional (3D) printing of hydrogels for tissue engineering is challenging. A new approach enabling rapid 3D printing of hydrogels in aqueous solutions is presented on the basis of UV-curable inks containing nanoparticles of highly efficient but water-insoluble photoinitiators. The extinction coefficient of the new water-dispersible nanoparticles of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) is more than 300 times larger than the best and most used commercially available water-soluble photoinitiator. The TPO nanoparticles absorb significantly in the range from 385 to 420 nm, making them suitable for use in commercially available, low-cost, light-emitting diode-based 3D printers using digital light processing. The polymerization rate at this range is very fast and enables 3D printing that otherwise is impossible to perform without adding solvents. The TPO nanoparticles were prepared by rapid conversion of volatile microemulsions into water-dispersible powder, a process that can be used for a variety of photoinitiators. Such water-dispersible photoinitiator nanoparticles open many opportunities to enable rapid 3D printing of structures prepared in aqueous solutions while bringing environmental advantages by using low-energy curing systems and avoiding the need for solvents.[on SciFinder (R)]
Banin U, Magdassi S, Shemesh S, Halivni S, Vinetsky Y.; 2016. Patterns of fluorescent seeded nanorods.Abstract
The invention provides novel means for fabricating patterns and objects comprising nanorods, while reducing inter-particle interaction. [on SciFinder(R)]
Cai P, Layani M, Leow WR, Amini S, Liu Z, Qi D, Hu B, Wu Y-L, Miserez A, Magdassi S, et al. Bio-Inspired Mechanotactic Hybrids for Orchestrating Traction-Mediated Epithelial Migration. Adv. Mater. (Weinheim, Ger.). 2016;28 (16) :3102 - 3110.Abstract

A platform of mechanotactic hybrids is established by projecting lateral gradients of apparent interfacial stiffness onto the planar surface of a compliant hydrogel layer using an underlying rigid substrate with microstructures inherited from 3D printed molds. Using this platform, the mechanistic coupling of epithelial migration with the stiffness of the extracellular matrix (ECM) is found to be independent of the interfacial compositional and topog. cues. [on SciFinder(R)]

Cai G, Darmawan P, Cui M, Wang J, Chen J, Magdassi S, Lee PS. Highly Stable Transparent Conductive Silver Grid/PEDOT:PSS Electrodes for Integrated Bifunctional Flexible Electrochromic Supercapacitors. Adv. Energy Mater. 2016;6 (4) :n/a.Abstract

Silver grids are attractive for replacing indium tin oxide as flexible transparent conductors. This work aims to improve the electrochem. stability of silver-based transparent conductors. A silver grid/PEDOT:PSS hybrid film with high cond. and excellent stability is successfully fabricated. Its functionality for flexible electrochromic applications is demonstrated by coating one layer of WO3 nanoparticles on the silver grid/PEDOT:PSS hybrid film. This hybrid structure presents a large optical modulation of 81.9% at 633 nm, fast switching, and high coloration efficiency (124.5 cm2 C-1). More importantly, an excellent electrochem. cycling stability (sustaining 79.1% of their initial transmittance modulation after 1000 cycles) and remarkable mech. flexibility (optical modulation decay of only 7.5% after 1200 compressive bending cycles) is achieved. A novel smart supercapacitor is presented that functions as a regular energy-storage device and simultaneously monitors the level of stored energy by a rapid and reversible color variation even at high current charge/discharge conditions. The film sustains an optical modulation of 87.7% and a specific capacitance of 67.2% at 10 A g-1 compared to their initial value at a c.d. of 1 A g-1. The high-performance silver grid/PEDOT:PSS hybrid transparent films exhibit promising features for various emerging flexible electronics and optoelectronic devices. [on SciFinder(R)]

Portnoy E, Vakruk N, Bishara A, Shmuel M, Eyal S, Magdassi S, Golenser J. Indocyanine Green Liposomes for Diagnosis and Therapeutic Monitoring of Cerebral Malaria. Theranostics. 2016;6 (2) :167 - 76.Abstract

Cerebral malaria (CM) is a major cause of death of Plasmodium falciparum infection. Misdiagnosis of CM often leads to treatment delay and mortality. Conventional brain imaging technologies are rarely applicable in endemic areas. Here we address the unmet need for a simple, non-invasive imaging methodology for early diagnosis of CM. This study presents the diagnostic and therapeutic monitoring using liposomes containing the FDA-approved fluorescent dye indocyanine green (ICG) in a CM murine model. Increased emission intensity of liposomal ICG was demonstrated in comparison with free ICG. The Liposomal ICG's emission was greater in the brains of the infected mice compared to naive mice and drug treated mice (where CM was prevented). Histological analyses suggest that the accumulation of liposomal ICG in the cerebral vasculature is due to extensive uptake mediated by activated phagocytes. Overall, liposomal ICG offers a valuable diagnostic tool and a biomarker for effectiveness of CM treatment, as well as other diseases that involve inflammation and blood vessel occlusion.[on SciFinder (R)]

Cai G, Darmawan P, Cui M, Chen J, Wang X, Eh AL-S, Magdassi S, Lee PS. Inkjet-printed all solid-state electrochromic devices based on NiO/WO3 nanoparticle complementary electrodes. Nanoscale. 2016;8 (1) :348 - 357.Abstract

Nanostructured thin films are important in the fields of energy conversion and storage. In particular, multi-layered nanostructured films play an important role as a part of the energy system for energy saving applications in buildings. Inkjet printing is a low-cost and attractive technol. for patterning and deposition of multi-layered nanostructured materials on various substrates. However, it requires the development of a suitable ink formulation with optimum viscosity, surface tension and evapn. rate for various materials. In this study, a versatile ink formulation was successfully developed to prep. NiO and WO3 nanostructured films with strong adhesion to ITO coated glass using inkjet printing for energy saving electrochromic applications. We achieved a high performance electrochromic electrode, producing porous and continuous electrochromic films without aggregation. The NiO film with 9 printed layers exhibits an optical modulation of 64.2% at 550 nm and a coloration efficiency (CE) of 136.7 cm2 C-1. An inkjet-printed complementary all solid-state device was assembled, delivering a larger optical modulation of 75.4% at 633 nm and a higher CE of 131.9 cm2 C-1 among all solid-state devices. The enhanced contrast is due to the printed NiO film that not only performs as an ion storage layer, but also as a complementary electrochromic layer. [on SciFinder(R)]

Yeshua T, Lehmann C, Hubner U, Azoubel S, Magdassi S, Campbell EEB, Reich S, Lewis A. Nanodrawing of Aligned Single Carbon Nanotubes with a Nanopen. Nano Lett. 2016;16 (3) :1517 - 1522.Abstract

Single-walled carbon nanotubes (SWCNTs) are considered pivotal components for mol. electronics. Techniques for SWCNT lithog. today lack simplicity, flexibility, and speed of direct, oriented deposition at specific target locations. In this paper SWCNTs are directly drawn and placed with chem. identification and demonstrated orientation using fountain pen nanolithog. (FPN) under ambient conditions. Placement across specific elec. contacts with such alignment is demonstrated and characterized. The fundamental basis of the drawing process with alignment has potential applications for other related systems such as inorg. nanotubes, polymers, and biol. mols. [on SciFinder(R)]

Cai G, Darmawan P, Cui M, Wang J, Chen J, Magdassi S, Lee PS. Supercapacitors: Highly Stable Transparent Conductive Silver Grid/PEDOT:PSS Electrodes for Integrated Bifunctional Flexible Electrochromic Supercapacitors. Adv. Energy Mater. 2016;6 (4) :n/a.