Prof. Levi A Gheber

Prof. Levi A Gheber Profile

Associate Professor

Department : Department of Biotechnology Engineering
Room : 136
בניין להנדסת ביוטכנולוגיה, ע"ש משפחת גוזיק - 42
Phone : 972-74-7795260
Email :
Office Hours :  


  • 1985-1988 B.Sc. Physics , Ben-Gurion University of the Negev, Beer-Sheva, Israel
  • 1988-1990 M.Sc. Physics of condensed matter, Ben-Gurion University of the Negev, Beer-Sheva, Israel. Title of thesis: "Investigation of metal islands by means of STM", advisors Prof. V. Volterra and Prof. G.Gorodetsky.
  • 1990-1995 Ph. D. Physics of condensed matter, Ben-Gurion University of the Negev, Beer-Sheva, Israel. Title of thesis: "Characterization of metal- semiconductor systems with STM" advisors Prof. V. Volterra and Prof. G. Gorodetsky.

Research Interests

  • Patterning of surfaces with molecular resolution, using Scanning Probe Microscopy (SPM) with applications in nanoelectronics.
  • Biochemical Nanophotolithography - Modification of biological surfaces using Near-field Scanning Optical Microscopy (NSOM) induced photochemistry - applications to biodevices (biochips, biosensors).
  • Clustering of membrane proteins - real time imaging of dynamic clusters of MHC-I proteins, using Total Internal Reflection Fluorescence Microscopy (TIRF), computerized image analysis and modeling - applications in controlling of immune system response.
  • Directing growth and differentiation of mesenchymal stem cells by micro patterning of the substrate, early stages of biomineralization and the biological mechanisms that dominate them.

Research Projects

  • Nano Fountain Pen protein printing.
  • Enzyme based nanolithography.
  • Dynamic clusters of MHC-I on plasma membrane of living cells.
  • Direct measurement of forces from cilia.
  • Directing growth and differentiation of mesenchymal stem cells by micro patterning of the substrate.
  • Early stages of biomineralization and the biological mechanisms that dominate them.
  • Nano-molecularly imprinted polimers (Nano-MIPs)

Research Abstract

  • Patterning, manipulating and characterizing biomaterials with two-photon NSOM : Scanning probe microscopy (SPM) techniques can, potentially, enable the transition from micro to nano scale in patterning, manipulating and analyzing surfaces, dictated by the increasing need for miniaturization and high-volume data storage. The SPM family, composed of the Scanning Tunneling Microscope (STM), Scanning Force Microscope (SFM or AFM), Near-field Scanning Optical Microscope (NSOM) and their derivatives, allow imaging, spectroscopic characterization, chemical identification, mechanical properties measurement and surface modification with molecular and atomic precision. NSOM is particularly suited for this goal due to a number of reasons. Biomaterials are tipycally non-conductive. This practically excludes STM as an adequate tool. AFM, despite its proven capabilities of high-resolution topographic imaging, lacks the ability to distinguish between different chemical species, which is very important for complex biomaterials. NSOM can yield a wealth of optical information and topography simultaneously, on non-conductive materials and operate in liquid. Using NSOM in combination with two-photon excitation has the power to overcome a number of problems that have limited patterning resolution so far.
  • Dynamic clusters of MHC-I on plasma membrane of living cells : Patches, lateral heterogeneities, of cell surface membrane proteins and lipids, have been imaged by a number of different microscopy techniques. This patchiness has been taken as evidence for the organization of membranes into spatial and functional domains, whose composition differs from the average for the entire membrane and which are specialized, for example for transmembrane signaling. However, the mechanism and specificity of patch formation are not understood. Hence we cannot infer much about the specificity of membrane domains. We have directly imaged patches of HLA class I molecules labeled with fluorescent antibody, using a Near-field Scanning Optical Microscope (NSOM); the patches measure ~300nm-600nm in diameter. Subsequently, we have proposed a model, illustrated by a computer simulation, which explains the mechanism for the formation of such patches, as a combination of lateral diffusion, barriers to lateral diffusion and vesicle traffic to and from the plasma membrane. According to our model, patches of this type can only be created and maintained in the presence of both barriers to lateral diffusion and vesicle traffic, when the latter keeps replenishing the concentration of proteins and thus avoids the dispersion of the patches by diffusion over the barriers. One of the most important predictions of this model is the dynamic character of the patches of proteins. In order verify the model predictions, we intend to undertake dynamic studies of the patches behavior. We propose to use for this purpose cells expressing GFP-tagged MHC class I proteins. We will use total internal reflection (TIR) microscopy to image the membrane of the cells, without exciting the fluorescence within the cytoplasm. By acquiring a time series of images of the plasma membrane, we will be able to check a number of key predictions of our model:1) The dynamic character of patches.For this purpose we will use the GFP-MHC I cells in combination with TIR microscopy, will anal
  • Biochemical nano-photolithography : The Near-field Scanning Optical Microscope (NSOM), used in this project, exploits the near-field effect to produce an optical image with a resolution well beyond the diffraction limit, by employing a tapered optical fiber probe to illuminate an area of ~ 100 nm diameter of the sample. Using the light emerging from the NSOM probe, we intend to induce photochemical reactions, which will enable us to bind proteins from the solution to the surface and/or break chemical bonds and release the photo-removable portion from areas of an immobilized organic film, conjugated to the substrate.This approach has the advantage of directing the photochemical reactions to areas with dimensions as small as 50 nm, with a positioning precision of 1 nm. This will allow us to create nano-scale patches and lines of deposited proteins, or patches and lines of indentations, where bonds have been cleaved. In addition, by employing a cyclic mode of operation, we will be able to bind several species of proteins onto the same restricted area, by flushing the liquid chamber and inserting a solution containing a different protein. We will also attempt nano-engraving of a protein-coated surface, with a proteolytic enzyme bound to the NSOM probe.

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