Marco Chiesa

Bio: Marco Chiesa is an academic researcher from Spanish National Research Council. The author has contributed to research in topics: Nanolithography & Nanowire. The author has an hindex of 5, co-authored 6 publications receiving 120 citations.

Large-scale nanopatterning of single proteins used as carriers of magnetic nanoparticles

Abstract: However, the supramolecular organization attained from‘‘bottom-up’’approachesiseitherdifficulttoextendfromnano-tomesoscopic length scales or does not allow accurate placement ofthe desired structures on a specific region of an inhomogeneoussurface. Similarly, a variety of methods based on Coulomb-force-directed assembly of nanoparticles have been proposed.

Detection of the early stage of recombinational DNA repair by silicon nanowire transistors.

Abstract: A silicon nanowire-based biosensor has been designed and applied for label-free and ultrasensitive detection of the early stage of recombinational DNA repair by RecA protein. Silicon nanowires transistors were fabricated by atomic force microscopy nanolithography and integrated into a microfluidic environment. The sensor operates by measuring the changes in the resistance of the nanowire as the biomolecular reactions proceed. We show that the nanoelectronic sensor can detect and differentiate several steps in the binding of RecA to a single-stranded DNA filament taking place on the nanowire-aqueous interface. We report relative changes in the resistance of 3.5% which are related to the interaction of 250 RecA·single-stranded DNA complexes. Spectroscopy data confirm the presence of the protein-DNA complexes on the functionalized silicon surfaces.

Electrical characteristics of silicon nanowire transistors fabricated by scanning probe and electron beam lithographies.

Abstract: Silicon nanowire (SiNW) field-effect transistors have been fabricated by oxidation scanning probes and electron beam lithographies. The analysis and comparison of the electron mobility and subthreshold swing shows that the device performance is not affected by the top-down fabrication method. The two methods produce silicon nanowire transistors with similar electrical features, although oxidation scanning probe lithography generates nanowires with smaller channel widths. The values of the electron mobility and the subthreshold swing, 200 cm2 V−1 s−1 and 500 mV dec−1, respectively, are similar to those obtained from bottom-up methods. The compatibility of top-down methods with CMOS (complementary metal–oxide–semiconductor) procedures, the good electrical properties of the nanowire devices and the potential for making sub-10 nanowires, in particular by using oxidation scanning probe lithography, make those methods attractive for device fabrication.

Nanoscale space charge generation in local oxidation nanolithography

Abstract: We have measured the surface potential and the space charge generated during the first stages of atomic force microscopy field-induced oxidation. Space charge densities are about 1017 cm−3 for oxidation times below 10 ms. In a dry atmosphere, the surface potential is negative. However, in humid air the surface potential could be either positive or negative. This effect is attributed to a screening effect of the water molecules. These results explain and support the use of local oxidation patterns as templates for building molecular architectures. They also establish the space charge build up as an intrinsic feature in local oxidation experiments.

Nanopatterning of Ferritin Molecules and the Controlled Size Reduction of Their Magnetic Cores

Abstract: A nanopatterning method to deposit ferritin proteins with nanoscale accuracy over large areas is reported. Selective deposition is driven by the electrostatic interactions existing between the proteins and nanoscale features. Upon deposition, the protein shell can be removed by heating the patterns in an oxygen atmosphere. This leaves exposed the iron oxide core, which can be further reduced in size by plasma-etching methods. In this way, the initial ferritin molecules, which have a nominal size of 12 nm, are reduced to 2 nm nanoparticles. Magnetic force measurements confirm the magnetic activity of the as-deposited and etched nanoparticles.

Advanced scanning probe lithography

Abstract: The nanoscale control afforded by scanning probe microscopes has prompted the development of a wide variety of scanning-probe-based patterning methods. Some of these methods have demonstrated a high degree of robustness and patterning capabilities that are unmatched by other lithographic techniques. However, the limited throughput of scanning probe lithography has prevented its exploitation in technological applications. Here, we review the fundamentals of scanning probe lithography and its use in materials science and nanotechnology. We focus on robust methods, such as those based on thermal effects, chemical reactions and voltage-induced processes, that demonstrate a potential for applications.

Ferritin: a versatile building block for bionanotechnology.

Abstract: Günther Jutz,†,§ Patrick van Rijn,†,‡,§ Barbara Santos Miranda,‡ and Alexander Böker*,† †DWI Leibniz-Institut für Interaktive Materialien e.V., Lehrstuhl für Makromolekulare Materialien und Oberflac̈hen, RWTH Aachen University, Forckenbeckstrasse 50, D-52056 Aachen, Germany ‡Department of Biomedical Engineering-FB40, W.J. Kolff Institute for Biomedical Engineering and Materials Science, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands

Tuning size and thermal hysteresis in bistable spin crossover nanoparticles.

Abstract: Nanoparticles of iron(II) triazole salts have been prepared from water−organic microemulsions. The mean size of the nanoparticles can be tuned down to 6 nm in diameter, with a narrow size distribution. A sharp spin transition from the low spin (LS) to the high spin (HS) state is observed above room temperature, with a 30−40-K-wide thermal hysteresis. The same preparation can yield second generation nanoparticles containing molecular alloys by mixing triazole with triazole derivatives, or from metallic mixtures of iron(II) and zinc(II). In these nanoparticles of 10−15 nm, the spin transition “moves” towards lower temperatures, reaching a 316 K limit for the cooling down transition and maintaining a thermal hysteresis over 15−20-K-wide. The nanoparticles were characterized by dynamic light scattering, TEM, and AFM, after deposition on gold or silicon surfaces. The spin transition was characterized by magnetic susceptibility measurements and EXAFS (in solid samples after solvent removal) and also by the colo...

Advances on structuring, integration and magnetic characterization of molecular nanomagnets on surfaces and devices

Abstract: This critical review represents a concise revision of the different experimental approaches so far followed for the structuration of molecular nanomagnets on surfaces, since the first reports on the field more than ten years ago. Afterwards, a presentation of the different experimental approaches followed for their integration in sensors is described. Such work involves mainly two families of sensors and devices, microSQUIDs sensors and three-terminal devices for single-molecule detection. Finally the last section is devoted to a detailed revision of the different experimental techniques that can be used for the magnetic characterization of these systems on surfaces, ranging from magnetic circular dichroism to magnetic force microscopy. The use of these techniques to characterize other nanostructured magnetic materials, such as nanoparticles, is also revised. The aim is to give a broad overview of the last advances achieved with these techniques and their potential and evolution over the next years.