icon sp96   SyncroPatch 384 application note:   logo pdf   (1.6 MB)
Cells were kindly provided by SB Drug Discovery and Charles River.


Automated patch clamp (APC) instruments are used for a wide variety of applications ranging from basic research into channelopathies and biophysical characteristics of ion channels, through to routine cardiac safety testing. Their use in cardiac safety screening has increased over the years and APC is now an established and accepted technique in most, if not all, safety testing laboratories. It is well known that fluoride is often used in the internal solution in APC experiments to improve the seal resistance. The presence of external calcium (or other divalent cation) further improves the seal by a mechanism thought to be due to the formation of CaF2 crystals at the interface between the pipette or micro-pore and the cell as described in a recent patent application.

Even in manual patch clamp experiments, fluoride has been used to record voltage gated Na+ channels for over 20 years, despite known effects on voltage dependence of conductance, and steady-state fast inactivation and its inhibition of protein phosphatase. Fluoride is used because it improves the seal and allows stable measurements to be performed over long periods of time. However, because there are some experiments where it is advantageous to use physiological, fluoride-free internal solutions and external solution that does not use divalent ‘seal enhancer’ solutions, we have developed a method that allows fluoride-free, physiological solutions to be used with good success rates. We demonstrate this using the cardiac ion channels hERG expressed in HEK293 cells (SB Drug Discovery) and NaV1.5 expressed in CHO cells (Charles River).


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