There has been much interest in improving the aspect ratio of AFM probes by fabricating needle-like structures on the probe tip to allow accurate profiling of samples with high, steep features. In addition, these so-called “nanoneedle” probes have recently shown great promise as tools for investigating biological cells, and are capable of penetrating the cell at a local site without damaging its overall structure. Many groups have used nanoneedle-like structures for the microinjection of biomolecules into cells, including for the injection of DNA into cell nuclei. These “nanosurgical” methods represent an entirely new way to study the structure of cells.

http://nanotechweb.org/cws/article/lab/45904