Publications (8)26.58 Total impact
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Article: Interconnection of specific nano-objects by electron beam lithography - A controllable method
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ABSTRACT: We report a widely applicable and highly controlled approach, based on electron beam lithography (EBL), to interconnect single nano-objects, previously immobilized onto solid surfaces, and to investigate the transport properties at the level of single nanostructures. In particular, a three-step EBL-procedure was used for this purpose by patterning two planar contacts on the sides of an individual nano-object. To demonstrate this approach, we use two different kinds of active elements: a semiconductor nanocrystal (tetrapod) and a thin triangular gold nanoprism (NT). (c) 2007 Elsevier B.V. All rights reserved.Materials Science & Engineering C-Biomimetic and Supramolecular Systems. 01/2008; 28(2):299-302. -
Article: Interconnection of specific nano-objects by electron beam lithography — A controllable method
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ABSTRACT: We report a widely applicable and highly controlled approach, based on electron beam lithography (EBL), to interconnect single nano-objects, previously immobilized onto solid surfaces, and to investigate the transport properties at the level of single nanostructures. In particular, a three-step EBL-procedure was used for this purpose by patterning two planar contacts on the sides of an individual nano-object. To demonstrate this approach, we use two different kinds of active elements: a semiconductor nanocrystal (tetrapod) and a thin triangular gold nanoprism (NT).Materials Science and Engineering: C. 01/2008; -
Article: Interconnecting single nano-objects on surfaces for transport experiments
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ABSTRACT: The authors report a highly controlled approach, based on electron-beam lithography, to interconnect individual nano-objects for transport experiments. The process is based on a three-step procedure, consisting of fabrication of four alignment markers, localization of the nano-object after its immobilization onto functionalized surfaces, and interconnection of the single nanostructure by patterning two nanoelectrodes on its sides. The approach is highly reproducible and widely applicable and allows an alignment accuracy of 15–20 nm . Here they demonstrate the reliability of such technique by using a thin triangular gold nanoprism as the active element and show the I-V characteristics of the single nanostructure.Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society 01/2006; 24(6):2765-2768. · 1.34 Impact Factor -
Article: Room‐Temperature Synthesis of Aragonite Crystals at an Expanding Liquid–Liquid Interface in a Radial Hele–Shaw Cell
Advanced Materials 08/2003; 15(15):1273 - 1278. · 13.88 Impact Factor -
Article: Assembly of CdS nanoparticles in patterned structures by a novel ion-entrapment process in thermally evaporated fatty acid films.
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ABSTRACT: The formation of cadmium sulfide nanoparticle assemblies in a patterned manner on suitable substrates is described. The protocol for realizing such structures comprises the following steps. In the first step, patterned films of a fatty acid are thermally evaporated onto solid supports using suitable masks (e.g., a transmission electron microscope grid). Thereafter, the fatty acid film is immersed in cadmium sulfate solution and Cd2+ ions entrapped in the lipid matrix by electrostatic complexation with the carboxylate ions of the fatty acid molecules. The final step involves reaction of the entrapped Cd2+ ions with Na2S, leading to the in situ generation of cadmium sulfide nanoparticles within the patterned lipid matrix. This approach shows promise for generating patterned nanoparticle assemblies of different chemical compositions.Journal of Nanoscience and Nanotechnology 10/2001; 1(3):281-5. · 1.56 Impact Factor -
Article: A new method for the generation of patterned protein films by encapsulation in arrays of thermally evaporated lipids.
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ABSTRACT: In this article we demonstrate a versatile method for the generation of patterned protein films by encapsulation in arrays of the lipids, octadecylamine (ODA, cationic), and arachidic acid (AA, anionic). A simple 2 x 2 array of ODA and AA was vacuum deposited on different substrates using appropriate masks. Thereafter, the enzymes pepsin and fungal protease as well as the heme-proteins cytochrome c and hemoglobin were encapsulated in the different elements of the array by sequential immersion (combined with judicious masking) of the array elements in the different protein solutions. The proteins are incorporated into the lipid elements by electrostatic interaction between charged amino acid residues on the protein surface and charged functional groups in the lipid matrix. This procedure leads to spatially distinct regions of the different proteins on one substrate and shows promise for single-chip multianalyte immunoassay/multiplex, high-throughput biosensor and catalysis applications. Fourier transform infrared spectroscopy (FTIR) was used to monitor the incorporation of the proteins in the different elements of the array as well as to ascertain whether intermixing of the proteins in a particular array element had occurred. The heme-protein composite regions were further characterized using UV-VIS spectroscopy.Biotechnology and Bioengineering 08/2001; 74(2):172-8. · 3.95 Impact Factor -
Article: Fabrication, characterization, and enzymatic activity of encapsulated fungal protease--fatty lipid biocomposite films.
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ABSTRACT: Encapsulation of an aspartic protease from the fungus Aspergillus saitoi (F-prot) in thermally evaporated fatty acid films by a simple beaker-based immersion technique under enzyme-friendly conditions is described. The approach is based on diffusion of the enzyme from aqueous solution, driven primarily by attractive electrostatic interaction between charged groups on the enzyme surface and ionized lipid molecules in the film. The encapsulated enzyme molecules could be "pumped out" of the biocomposite film into solution by modulating the electrostatic interaction between the enzyme and fatty acid molecules via solution pH variation. The kinetics of F-prot diffusion into the acid films was followed using quartz crystal microgravimetry measurements while the secondary and tertiary structure of the enzyme in the lipid matrix was studied using Fourier transform infrared (FT-IR) and fluorescence spectroscopies. FT-IR and fluorescence measurements indicated little perturbation to the native structure of the enzyme. A chemical analysis of the F-prot-fatty acid biocomposite film was also performed using X-ray photoelectron spectroscopy. The encapsulated F-prot molecules showed catalytic activity (as estimated by reaction with hemoglobin) comparable to free enzyme molecules in solution, indicating facile access of biological analytes/reactants in solution to the enzyme molecules. The advantages/disadvantages of this approach vis-à-vis methods currently used for encapsulation of biomolecules are briefly discussed.Analytical Chemistry 10/2000; 72(18):4301-9. · 5.86 Impact Factor -
Article: Isothermal titration calorimetry studies on the binding of amino acids to gold nanoparticles
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ABSTRACT: Isothermal titration calorimetry (ITC) is a powerful and highly sensitive technique commonly used to study interactions between biomolecules in dilute aqueous solutions, both from thermodynamic and kinetics points of view. In this report, we show that ITC may be used to follow the binding of ligands such as amino acids to the surface of inorganic materials such as gold nanoparticles. More specifically, we have studied the binding of one basic amino acid, lysine, and an acidic amino acid, aspartic acid, with aqueous gold nanoparticles at physiological pH. Strong binding of aspartic acid with the gold nanoparticles under these conditions is indicated by ITC, while weak binding was observed in the case of lysine. The differences in binding are attributed to protonation of amine groups in lysine at physiological pH (pI ∼ 9.4) while they are not protonated for aspartic acid (pI ∼ 2.77). That this is the likely mechanism is indicated by the ITC measurement of binding of lysine with nanogold at pH 11 (when the amine groups are not protonated). The binding of the amino acids with gold nanoparticles has been validated with other techniques such as gel electrophoresis and X-ray photoemission spectroscopy.Journal of Physical Chemistry B. 108(31):11535-11540.
Top co-authors
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Institutions
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2006–2008
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Università del Salento
- Department of Engineering for Innovation
Lecce, Apulia, Italy
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2000–2001
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National Chemical Laboratory
Pune, State of Maharashtra, India
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