Publications by Year: 2015

2015
Ratner N, Mandler D. Electrochemical detection of low concentrations of mercury in water using gold nanoparticles. Anal ChemAnalytical chemistry. 2015;87 (10) :5148 - 55.Abstract
The electrochemical detection of mercury in aqueous solutions was studied at glassy carbon (GC) and indium-tin oxide (ITO) electrodes modified by gold nanoparticles (Au NPs). Two methods of modification were used: electrochemical reduction of HAuCl4 and electrostatic adsorption of Au NPs stabilized by citrate. We found that the Au NPs modified surfaces yielded higher sensitivity and sharper and more reproducible stripping peaks of Hg as compared with the bare electrodes. The effect of the modification by Au NPs on the stripping potential was examined. Interestingly, the stripping of Hg on GC and ITO modified by Au NPs occurred at the same potential as on bare GC and ITO, respectively. Only the full coverage of ITO by either electrochemically deposited Au for a long time or by vapor deposition, shifted the stripping potential more positive by ca. 0.4 V to that observed on a bare Au electrode. These and further experiments led us to conclude that the Au NPs served as nucleation sites for the deposition of Hg, whereas the GC or ITO are superior for the stripping of mercury. Hence, a combination of well-defined Au NPs on ITO or GC were found ideal for the electrochemical detection of Hg. Indeed, we achieved a remarkable detection limit of 1 μm·L(-1) of Hg using an ITO surface modified by electrostatically adsorbed Au NPs.[on SciFinder (R)]
Peled Y, Krent E, Tal N, Tobias H, Mandler D. Electrochemical determination of low levels of uranyl by a vibrating gold microelectrode. Anal ChemAnalytical chemistry. 2015;87 (1) :768 - 76.Abstract
In this work we report the sensitive electroanalytical detection of uranium(VI) in aqueous solutions. Uranium commonly exists in aqueous solutions in the form of its oxo ion, uranyl (U(VI)O2(2+)). The detection of uranyl has been accomplished by us through its deposition upon reduction by two electrons to the insoluble UO2 using a bare disk gold macroelectrode and anodic stripping voltammetry (ASV). This gave an unsatisfactory detection limit of ca. 1 × 10(-5) M uranyl. Moreover, the evolution of hydrogen bubbles blocked the electrode surface as a result of water reduction at negative deposition potential (-0.7 V vs Ag/AgCl). The application of a 25 μm diameter Au microwire electrode on which UO2 precipitated at negative potential (-1.2 V) improved substantially the detection limit. Further improvement was accomplished by vibrating the microwire working electrode, which increased the amounts of UO2 deposition due to decreasing the diffusion layer. The effect of the vibrating amplitude and frequency on the electroanalytical response was studied and optimized. Eventually, a detection limit of ca. 1 × 10(-9) M uranyl was achieved using a 5 min deposition time, -1.2 V deposition potential, and vibrating the electrode at frequency of 250 Hz and amplitude of 6 V.[on SciFinder (R)]
Ratner N, Mandler D. Correction to Electrochemical Detection of Low Concentrations of Mercury in Water Using Gold Nanoparticles. Anal ChemAnalytical chemistry. 2015;87 (14) :7492.
Teodorescu F, Rolland L, Ramarao V, Abderrahmani A, Mandler D, Boukherroub R, Szunerits S. Electrochemically triggered release of human insulin from an insulin-impregnated reduced graphene oxide modified electrode. Chem Commun (Camb)Chemical communications (Cambridge, England). 2015;51 (75) :14167 - 70.Abstract
An electrochemical insulin-delivery system based on reduced graphene oxide impregnated with insulin is described. Upon application of a potential pulse of -0.8 V for 30 min, up to 70 ± 4% of human insulin was released into a physiological medium while preserving its biological activity.[on SciFinder (R)]
Gdor E, Shemesh S, Magdassi S, Mandler D. Multienzyme Inkjet Printed 2D Arrays. ACS Appl Mater InterfacesACS applied materials & interfaces. 2015;7 (32) :17985 - 92.Abstract
The use of printing to produce 2D arrays is well established, and should be relatively facile to adapt for the purpose of printing biomaterials; however, very few studies have been published using enzyme solutions as inks. Among the printing technologies, inkjet printing is highly suitable for printing biomaterials and specifically enzymes, as it offers many advantages. Formulation of the inkjet inks is relatively simple and can be adjusted to a variety of biomaterials, while providing nonharmful environment to the enzymes. Here we demonstrate the applicability of inkjet printing for patterning multiple enzymes in a predefined array in a very straightforward, noncontact method. Specifically, various arrays of the enzymes glucose oxidase (GOx), invertase (INV) and horseradish peroxidase (HP) were printed on aminated glass surfaces, followed by immobilization using glutardialdehyde after printing. Scanning electrochemical microscopy (SECM) was used for imaging the printed patterns and to ascertain the enzyme activity. The successful formation of 2D arrays consisting of enzymes was explored as a means of developing the first surface confined enzyme based logic gates. Principally, XOR and AND gates, each consisting of two enzymes as the Boolean operators, were assembled, and their operation was studied by SECM.[on SciFinder (R)]
Liu L, Yellinek S, Tal N, Toledano R, Donval A, Yadlovker D, Mandler D. Electrochemical co-deposition of sol-gel/carbon nanotube composite thin films for antireflection and non-linear optics. J. Mater. Chem. CJournal of Materials Chemistry C: Materials for Optical and Electronic Devices. 2015;3 (5) :1099 - 1105.Abstract
Sol-gel/carbon nanotube (CNT) nano-composite films were electrochem. deposited by applying a neg. potential to a conducting substrate, i.e. indium tin oxide (ITO) and an Ag grid printed on polyethylene terephthalate (PET). The deposition is driven by the local pH rise on the cathode that catalyzes the formation of sol-gel films. The latter serve as a binder and trap for CNTs. The deposition can be well manipulated by the deposition potential and time, and the film can be selectively electrodeposited on the conductive parts of Ag grids printed on PET from an optimized dispersion. The thickness, transmittance, morphol. and hydrophilicity of the films are characterized by profilometry, spectrophotometry, SEM (SEM) and water contact angle, resp. It is further revealed that the electrodeposited sol-gel/CNT composite films have non-linear optical properties and exhibit pronounced antireflective performance (specular reflection < 0.5%) over a visible to long-wave IR range, allowing their potential application as optical materials. [on SciFinder(R)]
Steele TWJ, Mandler D.; 2015. Electroactive bioadhesive compositions.Abstract
The present invention relates to electrochem. initiated bioadhesive compns. comprising biocompatible polymers contg. derivs. of diazonium, arylsulfonium, or diaryliodonium in general, and to their use in tissue fixation, in particular. [on SciFinder(R)]
Ratner N, Mandler D. Electrochemical Detection of Low Concentrations of Mercury in Water Using Gold Nanoparticles [Erratum to document cited in CA162:582409]. Anal. Chem. (Washington, DC, U. S.)Analytical Chemistry (Washington, DC, United States). 2015;87 (14) :7492.Abstract
The units of concn. of mercury noted as "μm L-1" should read as "ng L-1.". [on SciFinder(R)]
Ratner N, Mandler D. Electrochemical Detection of Low Concentrations of Mercury in Water Using Gold Nanoparticles. Anal. Chem. (Washington, DC, U. S.)Analytical Chemistry (Washington, DC, United States). 2015;87 (10) :5148 - 5155.Abstract
The electrochem. detection of Hg in aq. solns. was studied at glassy C (GC) and In-Sn oxide (ITO) electrodes modified by Au nanoparticles (Au NPs). Two methods of modification were used: electrochem. redn. of HAuCl4 and electrostatic adsorption of Au NPs stabilized by citrate. We found that the Au NPs modified surfaces yielded higher sensitivity and sharper and more reproducible stripping peaks of Hg as compared with the bare electrodes. The effect of the modification by Au NPs on the stripping potential was examd. Interestingly, the stripping of Hg on GC and ITO modified by Au NPs occurred at the same potential as on bare GC and ITO, resp. Only the full coverage of ITO by either electrochem. deposited Au for a long time or by vapor deposition, shifted the stripping potential more pos. by ∼0.4 V to that obsd. on a bare Au electrode. These and further expts. led us to conclude that the Au NPs served as nucleation sites for the deposition of Hg, whereas the GC or ITO are superior for the stripping of Hg. Hence, a combination of well-defined Au NPs on ITO or GC were found ideal for the electrochem. detection of Hg. We achieved a remarkable detection limit of 1 μm/L of Hg using an ITO surface modified by electrostatically adsorbed Au NPs. [on SciFinder(R)]
Peled Y, Krent E, Tal N, Tobias H, Mandler D. Electrochemical Determination of Low Levels of Uranyl by a Vibrating Gold Microelectrode. Anal. Chem. (Washington, DC, U. S.)Analytical Chemistry (Washington, DC, United States). 2015;87 (1) :768 - 776.Abstract
The authors report the sensitive electroanal. detection of uranium(VI) in aq. solns. Uranium commonly exists in aq. solns. as its oxo ion, uranyl (UVIO22+). The detection of uranyl was accomplished by the authors through its deposition upon redn. by two electrons to the insol. UO2 using a bare disk gold macroelectrode and anodic stripping voltammetry (ASV). This gave an unsatisfactory detection limit of ∼1 × 10-5 M uranyl. Also, the evolution of hydrogen bubbles blocked the electrode surface as a result of water redn. at neg. deposition potential (-0.7 V vs. Ag/AgCl). The application of a 25 μm diam. Au microwire electrode on which UO2 pptd. at neg. potential (-1.2 V) improved substantially the detection limit. Further improvement was accomplished by vibrating the microwire working electrode, which increased the amts. of UO2 deposition due to decreasing the diffusion layer. The effect of the vibrating amplitude and frequency on the electroanal. response was studied and optimized. Eventually, a detection limit of ∼1 × 10-9 M uranyl was achieved using a 5 min deposition time, -1.2 V deposition potential, and vibrating the electrode at frequency of 250 Hz and amplitude of 6 V. [on SciFinder(R)]
Magdassi S, Lee PS, Kamyshny A, Mandler D, Darmawan P, Layani M.; 2015. Electrochromic device.Abstract
A method of manufg. an electrochromic device is provided. The method includes providing a patterned arrangement of an elec. conductive material; and applying one or more layers of an electrochromic material to the patterned arrangement, wherein at least a portion of the electrochromic material is in elec. contact with the elec. conductive material. An electrochromic device and an electrochromic ink compn. are also provided. [on SciFinder(R)]
Ling H, Liu L, Lee PS, Mandler D, Lu X. Layer-by-Layer Assembly of PEDOT:PSS and WO3 Nanoparticles: Enhanced Electrochromic Coloration Efficiency and Mechanism Studies by Scanning Electrochemical Microscopy. Electrochim. ActaElectrochimica Acta. 2015;174 :57 - 65.Abstract
Layer-by-layer assembly method is employed to fabricate multilayer hybrid films based on poly(styrenesulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) and W oxide nanoparticles (WO3 NPs). Polyethylenimine (PEI) is deposited in between to introduce electrostatic force between the components. In the hybrid films, randomly oriented disk-like WO3 NPs are homogeneously distributed in the polymers and form an interdigitated structure. This very rough surface morphol. hinders the formation of a continuous PEI layer between the electrochromic layers. Owing to the efficient charge transfer between the two active components and complementary elec. cond. of the two components in the redox switching process, the coloration efficiency of the hybrid film is significantly improved to 117.7 cm2/C at wavelength of 633 nm. The underlying mechanism for the enhancement is verified by scanning electrochem. microscopic studies through probing the cond. changes of PEDOT:PSS, WO3-NP and hybrid films under various applied potentials. [on SciFinder(R)]
Gdor E, Shemesh S, Magdassi S, Mandler D. Multienzyme Inkjet Printed 2D Arrays. ACS Appl. Mater. InterfacesACS Applied Materials & Interfaces. 2015;7 (32) :17985 - 17992.Abstract
The use of printing to produce 2D arrays is well established, and should be relatively facile to adapt for the purpose of printing biomaterials; however, very few studies have been published using enzyme solns. as inks. Among the printing technologies, inkjet printing is highly suitable for printing biomaterials and specifically enzymes, as it offers many advantages. Formulation of the inkjet inks is relatively simple and can be adjusted to a variety of biomaterials, while providing nonharmful environment to the enzymes. Here we demonstrate the applicability of inkjet printing for patterning multiple enzymes in a predefined array in a very straightforward, noncontact method. Specifically, various arrays of the enzymes glucose oxidase (GOx), invertase (INV) and horseradish peroxidase (HP) were printed on aminated glass surfaces, followed by immobilization using glutardialdehyde after printing. Scanning electrochem. microscopy (SECM) was used for imaging the printed patterns and to ascertain the enzyme activity. The successful formation of 2D arrays consisting of enzymes was explored as a means of developing the first surface confined enzyme based logic gates. Principally, XOR and AND gates, each consisting of two enzymes as the Boolean operators, were assembled, and their operation was studied by SECM. [on SciFinder(R)]
Bruchiel-Spanier N, Mandler D. Nanoparticle-Imprinted Polymers: Shell-Selective Recognition of Au Nanoparticles by Imprinting Using the Langmuir-Blodgett Method. ChemElectroChemChemElectroChem. 2015;2 (6) :771.Abstract
The front cover artwork is provided by Prof. Mandler's group at the Hebrew University (Israel). The image shows the reuptake process in which only the particles with the original shell size are captured by the imprinted cavities, while the others are not recognized. Read the full text of the Article at10.1002/celc.201402407. [on SciFinder(R)]
Bruchiel-Spanier N, Mandler D. Nanoparticle-imprinted polymers: shell-selective recognition of Au nanoparticles by imprinting using the Langmuir-Blodgett method. ChemElectroChemChemElectroChem. 2015;2 (6) :795 - 802.Abstract
Speciation of nanoparticles, i.e., their differentiation based on size, shape and stabilizing shell is becoming important since their properties depend on these parameters. Nanoparticle-imprinted polymers (NIPs) are a new approach that aims to selectively recognize nanoparticles based on their structural properties. In this study, monolayers of cellulose acetate (CA) accommodating gold nanoparticles stabilized with dodecanethiol (AuNPs/C12) are transferred onto indium tin oxide (ITO) by the Langmuir-Blodgett technique. One to five monolayers are assembled. Electrochem. oxidn. dissolves the AuNPs/C12 to form cavities in the films, which fit the size and shape of the AuNPs/C12. Reuptake of the nanoparticles from a soln. is successful using the imprinted films, whereas the control films contg. only CA layers do not reuptake the AuNPs/C12. The NIPs are highly selective and other gold nanoparticles stabilized by other thiols are not recognized by the imprinted matrix. [on SciFinder(R)]
Fam DWH, Azoubel S, Liu L, Huang J, Mandler D, Magdassi S, Tok AIY. Novel felt pseudocapacitor based on carbon nanotube/metal oxides. J. Mater. Sci.Journal of Materials Science. 2015;50 (20) :6578 - 6585.Abstract
This work describes a novel supercapacitor electrode based on a glass fiber felt substrate, single-walled carbon nanotube (SWCNT) and metal oxide layers (RuO2 or MnO2). It is fabricated by the repeated and alternate deposition of SWCNTs and metal oxides via dipping and electrodeposition, resp., to achieve three-dimensional layered hierarchical structured supercapacitor electrodes. The results show that the layered structured electrodes fabricated by alternating deposition of SWCNTs and metal oxides have higher capacitance as compared with the bulk deposited samples, which are fabricated by deposition of SWCNTs followed by metal oxides. The best configuration studied in this work shows specific capacitance of 72 and 98 F/g for the SWCNT-MnO2 and SWCNT-RuO2, resp., whereas the corresponding areal capacitances are 0.07 and 0.09 F/cm2. This three-dimensional porous electrode structure design combines the high mech. stability of the felt substrate with the high cond. and sp. surface area of SWCNTs, and the high capacitance of metal oxides. This will add immensely to the research and development of wearable lightwt. electronics in harsh environments. [on SciFinder(R)]
Teodorescu F, Rolland L, Ramarao V, Abderrahmani A, Mandler D, Boukherroub R, Szunerits S. Electrochemically triggered release of human insulin from an insulin-impregnated reduced graphene oxide modified electrode. Chem. Commun. (Cambridge, U. K.)Chemical Communications (Cambridge, United Kingdom). 2015;51 (75) :14167 - 14170.Abstract
An electrochem. insulin-delivery system based on reduced graphene oxide impregnated with insulin is described. Upon application of a potential pulse of -0.8 V for 30 min, up to 70 ± 4% of human insulin was released into a physiol. medium while preserving its biol. activity. [on SciFinder(R)]
Bera RK, Azoubel S, Mhaisalkar SG, Magdassi S, Mandler D. Fabrication of Carbon Nanotube/Indium Tin Oxide "Inverse Tandem" Absorbing Coatings with Tunable Spectral Selectivity for Solar-Thermal Applications. Energy Technol. (Weinheim, Ger.)Energy Technology (Weinheim, Germany). 2015;3 (10) :1045 - 1050.Abstract
We report the fabrication of a new selective "inverse tandem" absorbing coating based on carbon nanotube (CNT)/indium-tin oxide (ITO) on aluminum (Al) for mid-temp. solar-thermal application. The CNT layer is formed by spraying and functions as an excellent solar absorber whereas the ITO layer produced on top of the CNTs by sputtering serves as an IR reflector. The effect of the thickness of the ITO on the spectral selectivity of the absorbing coating was investigated. Controlling the thickness of ITO allowed the spectral selectivity of the coating to be tuned. The CNT/ITO solar coatings with optimized thickness of ITO showed excellent spectral selectivity values of absorptance (α) of 0.927 and emittance (ε) of 0.2. The performance of the coatings at high temp. after heating in air in the range of 25-300°C for different durations was also investigated. The performance and structure of the CNT/ITO coating was also compared with the wet deposition method in which the ITO coating was formed by spraying. [on SciFinder(R)]
Liu L, Yellinek S, Valdinger I, Donval A, Mandler D. Important Implications of the Electrochemical Reduction of ITO. Electrochim. ActaElectrochimica Acta. 2015;176 :1374 - 1381.Abstract
The electrochem. redn. of indium tin oxide (ITO) on glass is systematically studied. The light absorbance and elec. resistance of ITO increases upon redn. SEM images show that the integrate ITO films dissolve and form particles upon applying neg. potentials. The particles consist of metallic In and Sn, as characterized by XRD and XPS. The redn. of ITO strongly depends on the electrolyte conditions, mainly pH and anions. The onset potential is found to shift neg. as the pH of the electrolyte increases. NO-3 ions significantly inhibit the redn. of ITO, shifting the redn. potential neg. by ∼500 mV as compared with SO2-4, Cl- and Br-. It can also serve as inhibitor by adding very low concn. to the Cl--dominant electrolyte. Also, the electrochem. reduced ITO show excellent nonlinear optical performance, with transmittance tuneable by redn. potential and time. This suggests a promising useful application of the electrochem. redn. of ITO. [on SciFinder(R)]
Magdassi S, Zwicker C, Mhaisalkar SG, Mandler D, Levi L, Azoubel S.; 2015. Spectrally selective solar thermal coating combining a light-absorbing coating and an infrared reflecting layer positioned on top of the absorber coating.Abstract
The invention relates to a light-absorbing element coated on at least a region of its surface with a film of at least one light-absorbing material, the light-absorbing material being assocd. with at least one binder material, the film being 1 - 20 μm thick and having light absorption of at least 90%. The invention also relates to a device comprising a light-absorbing element. The invention also claims a thermosolar device comprising a light-absorbing element. The invention also relates to a method of fabricating a light-absorbing film on a surface region of a substrate, the method comprising: (a) forming on a surface region at least one absorbing layer comprising: (I) a light-absorbing material; and (II) a polymerizable binder resin; (b) heating the at least one absorbing layer to induce polymn. of the binder resin; and (c) optionally forming at least one IR radiation reflecting layer on the polymd. binder. [on SciFinder(R)]