Publications (34) View all
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Article: AFM Nanotools for Surgery of Biological Cells
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ABSTRACT: Using a method of electron-beam induced deposition, we have been able to fabricate specialized AFM probes with application as "nanotools" for the manipulation of biological structures ("nanosurgery"). We describe several such tools, including a "nanoscalpel", "nanoneedles" for probing intracellular structures, and a "nanotome" which can separate surface layers from a biological structure. These applications are demonstrated by performing nanomanipulation on corneocyte cells from the outer layer of human skin.Journal of Physics Conference Series 04/2011; 286(1):012003. -
Article: Fabrication and buckling dynamics of nanoneedle AFM probes.
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ABSTRACT: A new method for the fabrication of high-aspect-ratio probes by electron beam induced deposition is described. This technique allows the fabrication of cylindrical 'nanoneedle' structures on the atomic force microscope (AFM) probe tip which can be used for accurate imaging of surfaces with high steep features. Scanning electron microscope (SEM) imaging showed that needles with diameters in the range of 18-100 nm could be obtained by this technique. The needles were shown to undergo buckling deformation under large tip-sample forces. The deformation was observed to recover elastically under vertical deformations of up to ∼ 60% of the needle length, preventing damage to the needle. A technique of stabilizing the needle against buckling by coating it with additional electron beam deposited carbon was also investigated; it was shown that coated needles of 75 nm or greater total diameter did not buckle even under tip-sample forces of ∼ 1.5 µN.Nanotechnology 04/2011; 22(17):175303. · 3.98 Impact Factor -
Article: Large flexibility of high aspect ratio carbon nanostructures fabricated by electron-beam-induced deposition.
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ABSTRACT: The mechanical properties of free-standing electron beam deposited amorphous carbon structures have been studied using atomic force microscopy. The fabricated carbon blades are found to be extraordinarily flexible, capable of undergoing vertical deflection up to ∼ 75% of their total length without inelastic deformation. The elastic bending modulus of these structures was calculated to be 28 ± 10 GPa.Nanotechnology 11/2010; 21(47):475702. · 3.98 Impact Factor -
Article: Fabrication of shuttle-junctions for nanomechanical transfer of electrons.
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ABSTRACT: We report on the fabrication of nanomechanical devices for shuttling of electrons from one electrode to another. Each device consists of a 20 nm diameter gold nanoparticle embedded within the gap between two gold electrodes. In two different kinds of shuttle-junctions the nanoparticle is attached to the electrodes through either (i) a single layer of 1,8-octanedithiol or (ii) a multilayer of 1-octanethiol molecules. The thiol layers play the role of 'damped springs', such that when a sufficient voltage bias is applied to the junction, the nanoparticle is expected to start oscillating and thereby transferring electrons from one electrode to the other. For both kinds of shuttle-junctions we observed an abrupt increase in the transmitted current above a threshold voltage, which can be attributed to a transition from the stationary to the oscillating regime. The threshold voltage was found to be lower for single-layer shuttle-junctions.Nanotechnology 12/2009; 20(48):485202. · 3.98 Impact Factor -
Article: An atomic force microscope nanoscalpel for nanolithography and biological applications.
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ABSTRACT: We present the fabrication of specialized nanotools, termed nanoscalpels, and their application for nanolithography and nanomechanical manipulation of biological objects. Fabricated nanoscalpels have the shape of a thin blade with the controlled thickness of 20-30 nm and width of 100-200 nm. They were fabricated using electron beam induced deposition at the apex of atomic force microscope probes and are hard enough for a single cut to penetrate a approximately 45 nm thick gold layer; and thus can be used for making narrow electrode gaps required for fabrication of nanoelectronic devices. As an atomic force microscope-based technique the nanoscalpel provides simultaneous control of the applied cutting force and the depth of the cut. Using mammalian cells as an example, we demonstrated their ability to make narrow incisions and measurements of local elastic and inelastic characteristics of a cell, making nanoscalpels also useful as a nanosurgical tool in cell biology. Therefore, we believe that the nanoscalpel could serve as an important tool for nanofabrication and nanosurgery on biological objects.Nanotechnology 11/2009; 20(44):445302. · 3.98 Impact Factor
