Dr Pavel Novak. Life at the tip of a nanopipette.
Date: 16 April 2014 Time: 15:00 - 16:00
Pipettes, in one form or another, have been used for sampling and transferring liquids in biology and chemistry for almost three centuries. The functionality of this rather simple but effective tool has been dramatically revolutionised in the 80s with the invention of the Nobel Prize - winning patch-clamp technology based on glass micropipettes, and scanning ion conductance microscopy (SICM) utilising glass nanopipettes. However, it was not until the beginning of the 21st century that the true power of nanopipette techniques for nanoscale physiology, biotechnology and electrochemistry was fully recognised.
SICM uses ion current flowing out of the tip of a glass nanopipette (tip diameter < 100 nm) filled with electrolyte to detect presence of a surface in a noncontact fashion. By scanning the sample in x-y plane and moving the nanopipette up and down on the z-axis the SICM recreates 3D topography image of the sample surface. We have shown that SICM is capable of recording 3D topography at resolution better than 20 nm in all three dimensions even in case of extremely complex live biological samples such as neuronal networks (Fig.1) or inner ear hair cells (1) – samples still mostly “out of reach” for other scanning probe microscopy techniques including the well know atomic force microscopy. The applications of the nanopipette mounted on a 3D nanopositioning stage expanded over the last decade from pure 3D imaging to functional mapping, 3D nanoprinting, nanopipetting, and nanoscale electrochemistry. Recently, we have successfully used SICM combined with the patch-clamp technique to record for the first time electrical activity at submicron synaptic terminals (2) (Fig.1, inset) and improved the scan speed to follow the dynamic interactions of single nanoparticles with membrane protrusions of lung epithelial cells (3). All these developments are only just beginning to open a new window into the life at nanoscale and have a potential to significantly contribute to our understanding of the nano-bio interface as well as provide new opportunities for engineering at nanoscale.
1. Novak, P. et al. Nat. Methods 6, 279-281 (2009).
2. Novak, P. et al. Neuron 79, 1067-1077 (2013).
3. Novak, P. et al. Nano Lett. 14, 1202-7 (2014).