61st Annual Gaseous Electronics Conference
Volume 53, Number 10
Monday–Friday, October 13–17, 2008;
Dallas, Texas
Session GW2: Charged Particle Surface Interactions
8:00 AM–9:30 AM,
Wednesday, October 15, 2008
Room: Salon A-D
Chair: Steve Shannon, North Carolina State University
Abstract ID: BAPS.2008.GEC.GW2.1
Abstract: GW2.00001 : Organising Atoms, Clusters and Proteins on Surfaces
8:00 AM–8:30 AM
Preview Abstract
Abstract
Author:
Richard E. Palmer
(Nanoscale Physics Research Laboratory, The University of Birmingham, Birmingham B15 2TT, UK)
This talk will discuss new developments in the creation of
nanoscale surface
features and their applications in biomedicine. Electron-surface
interactions and plasma methods play a crucial role in both the
production
and analysis of these ``atomic architectures.'' At the extreme
limit, electron
injection from the tip of a scanning tunnelling microscope (STM)
enables
bond-selective manipulation of individual polyatomic molecules
[1]. On a
more practical level, the controlled deposition of size-selected
clusters
[2], generated by magnetron sputtering and gas condensation
followed by mass
selection, represents a surprisingly efficient route to the
fabrication of
surface features of size 1-10 nm, the size scale of biological
molecules
such as proteins. STM and AFM measurements show the clusters can
act as
binding sites for individual protein molecules. For example, the
pinning of
size-selected AuN clusters (N = 1--2000) to the (hydrophobic)
graphite
surface presents bindings site for sulphur atoms and thus for the
cysteine
residues in protein molecules. Systematic studies of different
proteins [3]
provide ``ground rules'' for residue-specific protein
immobilisation by
clusters and have led to the development of a novel biochip for
protein
screening by a spin-off company. The 3D atomic structure of the
clusters is
highly relevant to such applications. We show that measurement of
the
scattered electron beam intensity - specifically, the high angle
annular
dark field (HAADF) signal - in the scanning transmission electron
microscope
(STEM) allows us (a) to count the number of atoms in a cluster on
the
surface and (b) to determine a 3D atom-density map of the cluster
when an
aberration-corrected STEM is used [4]. \newline
1. P.A. Sloan and R.E. Palmer, Nature 434 367 (2005). \newline
2. S. Pratontep, P. Preece, C. Xirouchaki, R.E. Palmer, C.F.
Sanz-Navarro,
S.D. Kenny and R. Smith, Phys. Rev. Lett. 90 055503 (2003). \newline
3. R.E. Palmer, S. Pratontep and H.-G. Boyen, Nature Materials 2
443 (2003);
R.E. Palmer and C. Leung, Trends in Biotechnology 25 48 (2007).
\newline
4. Z.Y. Li, N.P. Young, M. Di Vece, R.E. Palmer, A.L. Bleloch,
B.C. Curley,
R.L. Johnston, J. Jiang, J. Yuan, Nature 451 46 (2008).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.GEC.GW2.1