The perfusion system takes advantage of the computer controlled stepper motor and the DAQ board that are included in the ChannelMAX and PatchMAX systems to achieve fast and easy solution changes. With the specially designed perfusion chamber, making a solution change is as simple as clicking a button, and as fast as 20 ms. There is no dead space during a solution change.


Structure of the Perfusion Chamber II

The Perfusion Chamber II is designed for fast solution exchanges for excised patch and cultured cell whole cell patch. The structure of the Perfusion Chamber II for cultured cells is indicated in the figure below. It contains two slots for three barrel perfusion pipettes, a cell well for suspended cells, and a flat area for cells on the coverslip. The structure of the Perfusion Chamber II for oocytes is similar except it replaces the cell well with a cone shape well for oocyte.

The Perfusion Chamber II includes two perfusion systems: the whole bath perfusion system and the three-barrel pipette fast perfusion system. The bath perfusion system is designed for experiments that do not require fast solution changes. It can also be used as a background perfusion to keep the cells from being contaminated by drugs when the three-barrel pipette fast perfusion system is used. The bath perfusion outlet is in a chamber separated from the chamber that the patch pipette is in so to minimize vibration from perfusion.

The three-barrel perfusion pipettes are mounted in alignment with the direction of the patch pipettes' movement. The positions of the perfusion pipettes are adjustable so that they can be placed as close to the patch pipette as possible. When a patch pipette moves forward or backward, it passes the solution flow of the perfusion pipette. After making seal, the electrode lifts the cell up and brings it to the perfusion pipette. The process is controlled by a computer.

Software Controlled Solution Change

When an experiment is started, the patch pipette moves forward. The NBSController program that comes with the ChannelMAX and PatchMAX systems records currents while the pipette is moving. If the three barrels have distinctive solutions, (for instance, one barrel has a high salt concentration and another has a low salt concentration), the junction potentials of each will be different when the patch pipette passes different barrels. One example of the perfusion profile is shown below. Placing the cursors at the center of each peak will mark the locations of the center of each barrel.

Once the locations of the three barrel pipettes are marked, the software controls the stepper motor so that the patch pipette stops at the center of each barrel for the desired solution. Clicking on each of the three buttons (See figure below) will bring the patch pipette to the corresponding positions. When users want multiple solution changes, they may change the solution in barrel 2 and 3 while the electrode stays in barrel 1. There can be an unlimited number of solutions people can change with this system.

Solution Change is Fast

As shown in the above figure of a current profile, the transition from the first solution to the second is about 0.1 mm. Since the patch pipette movement is 4.8 mm/s, the solution changes in 20 ms. This is fast enough for most of the applications.


Perfusion Chamber II Specifications

Perfusion Chamber Size 2.14in x 1.5 in x 0.43in Bath Inlet Accept 1/16" tubing Bath Outlet Accept 1/16" tubing

Material Polycarbonate Three Barrel Pipette 0.6 mm x, 5 cm (ID x L) Warner Instruments part number 64-0119

US Price

$950

Contact us for international pricing.