At the apex of the probe is a blade-like structure composed of amorphous carbon, a material far more robust than the crystalline silicon which makes up standard AFM probes. Using an AFM system this probe can be used for solid state nanofabrication, and for the manipulation of biological cells. The nanoscalpel blades are fabricated on AFM probes using electron beam induced deposition (EBID). In this process, hydrocarbon vapour present in the vacuum chamber of a scanning electron microscope (SEM) is decomposed by the electron beam and the lighter, volatile hydrogen-rich fraction of the molecules is extracted by the vacuum system while the heavier carbon is deposited onto surfaces near the electron beam. The deposited carbon can be used to create nanoscale structures, and by moving the electron beam it is possible to fabricate 3-D nanostructures such as the nanoscalpel blades.
In solid-state nanofabrication, the group uses the nanoscalpel to cut 20-50nm wide gaps into metal films, forming a pair of contacts for the investigation of the electronic properties of nanoparticles and other nano-objects. Such gaps are difficult to fabricate reliably using conventional nanofabrication techniques but can be quickly and reproducibly created using a nanoscalpel. In biology the group have shown that the nanoscalpel can make fine incisions on the surface of fixed cells and they believe that it has the potential to be used for the isolation of parts of the cell and the cutting or extraction of individual organelles or protein filaments, both in living and fexed cells. They feel there is also the potential to dissect individual cells, exposing their internal structure for imaging in situ. This makes nanoscalpel the smallest surgical implement in existence! Capable of cutting structures much smaller than the single cell.
The nanoscalpel offers several significant advantages over other existing nanomanipulation techniques, such as laser microscalpels. The use of an AFM system allows the nanoscalpel to be positioned with sub-nanometre accuracy, and since the AFM is also capable of high precision force measurement, both the position of the scalpel and the force applied to the cell can be accurately determined. With this data, it is possible to distinguish and determine the elastic and inelastic deformation of the cell by the scalpel.
All this means that the nanoscalpel and other nanotools have the potential to significantly expand the range of nanosurgical techniques which can be performed using AFM, and would be useful in many fields including cell biology, pharmacology and medicine.