Electrodes, patch-clamp recording

The need to plasma-treat the PDMS surface just before use may be a disadvantage of the planar electrode. This would add a plasma system to the required equipment for patch clamp experiments. However, the planar electrodes do not require use of the high-quality optical microscope and micromanipulators currently required for patch clamp recording. In addition, conventional patch pipettes commonly require several processing steps before use including heat polishing and coating. 

Figure 15.1. Drosophila embryonic neuromuscular preparation. Top panel) Dissected Drosophila embryo viewed with a scanning electron microscope (SEM) anterior (A) to the left, posterior (P) to the right. The prominent CNS lies along the ventral midline. Bottom panel) Schematic drawing of the four ventral longitudinal muscles in one segment. The CNS, peripheral nerve, and NMJ on these four muscles are drawn. The typical recording configuration involves whole-cell patch-clamp recording from muscle 6 and suction-electrode stimulation of the peripheral nerve.

The patch electrode voltage-clamp is the method of choice to study V, alterations (Hamill et al., 1981). However, the high resistance seals required for these studies are not readily formed on mammalian sperm due both to geometric factors as well as the low compliance of the plasma membrane (Arnoult et al., 1996b). To date, recordings of whole cell currents, as is essential for monitoring of V, have not been reported in sperm, despite the heroic efforts exerted to obtain excised patches from these cells (Espinosa et al., 1998). As an alternative, has been ex-... 

For patch clamp measurements, the PDMS planar electrode array was plasma oxidized and then motmted in the recording system shown in Fig. 6. To electrically isolate each electrode, the partition was sealed onto the chamber bottom over an array of openings that each contained an Ag-AgCl wire and suction tubing. The Ag-AgCl wire was connected to the multiplexer chip mounted on the circuit board under the chamber. The multiplexer then connected to the input of the amplifier. The tubing connected to a suction manifold that permitted individual or global suction. 

Electrophysiology Recordings To record currents from sealed cells, the silicon chip assembly was used as a chamber for a voltage clamp setup (Fig. 6). Each half of the chamber (top and bottom) was connected to the electrodes of a headstage. The top chamber was connected to the input of the patch clamp amplifier, and the bottom chamber was connected to either the ground or the command voltage depending on the amplifier used. 

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