Bart Hoogenboom

High-resolution atomic force microscopy in liquid
Solid-liquid interfaces
Single-molecule biophysics
Molecular machines
Membrane proteins
Nanomechanical resonators

Contact details:
Office: Room B101
Tel office: +44(0)20 7679 0606
Tel lab: +44(0)20 7679 0618
Extension: 30606 / 30618
Fax: +44 (0)20 7679 0595
Email: b.hoogenboom

ucl.ac.uk

Research Interest
I am fascinated by the opportunities of nanotechnological tools to study and manipulate single atoms and molecules. I believe that there is a particular interest in exploiting these tools to investigate the molecular machines that make the biological cell function in a way similar to a macroscopic factory and yet - because of their nanometre-scale size and the presence of an aqueous environment - so different.

My research has a strong focus on scanning probe techniques. Of all scanning probe microscopes, the atomic force microscope (AFM) is the most popular for biological applications. Using an extremely sharp tip, it allows users to scan a surface just like a person's fingertip reading Braille, “touching” and “feeling” single molecules and/ or atoms. Moreover, since the AFM can be operated in liquid, we can probe and image biomolecules under conditions that are very near to those in a living cell.

Precise control of the AFM cantilever, our miniature "fingertip", is crucial to gently probe molecules without damaging or distorting them. In our laboratory, we develop new techniques to get complete control of the cantilever in aqueous environment, with the aim of probing and imaging biologically relevant samples with sub-molecular or even atomic resolution. We apply these techniques to a variety of samples, preferably to molecules of biomedical relevance.

Biography

2007-present, Lecturer in the London Centre for Nanotechnology and the Department of Physics and Astronomy, University College London
2005-2007, Post-Doctoral Research Assistant, Biozentrum, University of Basel, Switzerland, Laboratory of Prof. Andreas Engel
2002-2005, Post-Doctoral Research Assistant, Department of Physics, University of Basel, Switzerland, Laboratory of Prof. Hans Hug
1998-2002, Ph. D. Condensed Matter Physics, University of Geneva, Switzerland, Laboratory of Prof. Øystein Fischer
1998, M. Sc. Surface Physics, University of Groningen, the Netherlands, Laboratory of Prof. George Sawatzky

Selected and recent publications (click here for a full list of publications)

R. R. Grüter, Z. Khan, R. Paxman, J. W. Ndieyira, B. Dueck, B. A. Bircher, J. L. Yang, U. Drechsler, M. Despont, R. A. McKendry, and B. W. Hoogenboom, "Disentangling mechanical and mass effects on nanomechanical resonators", Appl. Phys. Lett. 96, 023113 (2010) [online article].
N. Jenkins, Y. Fasano, C. Berthod, I. Maggio-Aprile, A. Piriou, E. Giannini, B. W. Hoogenboom, C. Hess, T. Cren, and Ø. Fischer, "Imaging the essential role of spin fluctuations in high-Tc superconductivity", Phys. Rev. Lett.103, 227001 (2009) [online article].
C. Leung, H. Kinns, B. W. Hoogenboom, S. Howorka, and P Mesquida, "Imaging surface charges of individual biomolecules", Nano Lett. 9, 2769 (2009) [online article].
B. W. Hoogenboom, K. Suda, A. Engel, and D. Fotiadis, “Supramolecular assemblies of the voltage-dependent anion channel in the native membrane”, J. Mol. Biol. 370, 246 (2007). [online article][front cover]
B. W. Hoogenboom, H. J. Hug, Y. Pellmont, S. Martin, P. L. T. M. Frederix, D. Fotiadis, and A. Engel, “Quantitative dynamic-mode scanning force microscopy in liquid”, Appl. Phys. Lett. 88, 193109 (2006). [online article][News Feature in Nature on this research]

Teaching

PHASM800/PHASG800 Molecular Biophysics, term 2 (2009/2010)
PHAS3255 Solid State Physics, evening course, term 2 (2008/2009)

Research

Figure 1: Atomic and molecular resolution in liquid.
The forces between cantilever tip and sample can be precisely determined from shifts in the cantilever resonance frequency (frequency-modulation AFM). Combined with a highly-sensitive deflection detector, this technique allows atomic-resolution images (left, showing atomic-scale defects) of mica and molecular-resolution images of the membrane protein bacteriorhodopsin (right, here imaged in a 2D lattice), all in physiological buffer solution.

Figure 2: VDAC in the native membrane.
Outer mitochondrial membranes were purified and adsorbed on a mica substrate. Subsequent frequency-modulation AFM images show the VDAC assembling in monomers, dimers, trimers, tetramers, hexamers and higher oligomers. VDAC, appearing as a ring in the image, has an outer diameter of about 5 nm.