Electron Beam Deposited Nanotools for Nanomanipulation and Biological Applications

Abstract

This thesis describes the fabrication of a variety of \nanotool" structures which are fabricated on Atomic Force Microscope (AFM) probe tips. The structures are fabricated on standard AFM probes using a method of electron beam induced deposition (EBID), forming an amorphous carbon structure on the probe tip. Experiments are described which demonstrate the successful application of these probes for a variety of di�erent manipulation applications, focussing on the nanomanipulation of biological cells. A variety of tools are described, including \nanoscalpel" probes able to cut and section biological materials on very small scales, \nanoneedles" which function as high aspect ratio AFM probes or as probes of intracellular structures, \nanotweezers" and a \nanotome" which can be used to remove thin layers of material from a biological sample. A variety of techniques to fabricate complex nanotool structures and to strengthen the structures against large applied forces are described. Using these tools, the investigation of a variety of cell types including smooth muscle cells, megakaryocytes and corneocytes has been performed. Results are presented showing the \nanodissection" of these cells to expose their internal structures for in situ AFM imaging, and the detection of the mechanical properties of intracellular structures by indentation using nanoneedle probes. Extraction of samples from the outer corni�ed envelope of corneocyte cells using a nanoneedle probe is also demonstrated. The mechanical properties of the amorphous carbon making up these nanotools are also characterised using AFM manipulation, and their elastic bending modulus determined using models based on the Euler-Bernoulli beam bending equation. The structures are shown to be highly exible, with thin nanoneedle structures able to buckle elastically under large tip-sample forces in a manner similar to the high aspect ratio carbon nanotubes which are currently used as AFM probes.

Date of Award	1 Mar 2011
Original language	English
Awarding Institution	University of Bath
Supervisor	Sergey Gordeev (Supervisor)