(SF-77C, SF-77CLT, SF-77CST) Perfusion Fast-Step

Multiple Solution Studies

This is accomplished by having up to six solutions feeding through a manifold connected to each of the three "pipes" in front of which the cell may be placed. This allows any of the pipes to have any one of the multiple solutions flowing through it at any given time. It is also possible during the course of an experiment to change the solutions flowing into any of the manifolds, allowing a virtually limitless number of solutions to be used.

Acquiring this capability is best achieved by combining the SF-77C with a VCS-6M or VCS-8M mini valve system. This package can be seen on the VCS-77C webpage.

Bath vs Stepper solution flows

It's important to note that in addition to managing solution flow out of the SF-77C perfusion tubes, the flow within the larger chamber also needs to be managed since all flow velocities need to be the same.

A properly configured system will have a standard valve control system (such as the VCS-8P) dedicated to controlling the main bath flow, and a separate, smaller valve control system (such as the VCS-6M) dedicated to managing solution flow within the SF-77C perfusion tubes.

Having separate valve control systems for these two paths is critical for proper operation since the relative volumes and flow rates between the two are dramatically different and one controller cannot service both demands simultaneously.

Manual or External Control

The stepper mechanism can be manually controlled via the front panel or externally directed from your data acquisition program. Manually, the system can be stepped to 8 positions in 7 equally spaced steps. These same 8 positions can also be directly selected by applying an analog signal to the external analog input BNC or by passing a 3 bit word to the TTL inputs on the instrument rear panel.

Square Glass Ports

The square glass tubes used for solution delivery significantly reduces mixing turbulence, allowing the SF-77C to be used for studies with both membrane patches and whole cells, even when the cells are not fixed to a substrate.

System Versatility

Larger ports are required when using the SF-77C with larger cell structures such as the Xenopus oocyte. Solutions are delivered through 1.0 mm ID square tubes (SG1000-5) with barrel-to-barrel spacing of 1.4 mm. Micromanipulator and magnetic base not included.

The SF-77C/5M is the same system as the SF-77C except that it is provided with five perfusion manifolds. Micromanipulator and magnetic base not included.

Very fast perfusion stepping is possible using 2-barrel Theta tubing. The technique requires close attention to detail with careful placing of the pipes and the excised patch. The tubing is pulled on a standard puller for a tip diameter of approximately 300 um and a barrel spacing of approximately 100 um.

When using 100 um steps, it is important to minimize any vibration produced by the stepper motor. This is accomplished by reducing the motor voltage via the control located on the instrument rear panel. The voltage is lowered until the vibration artifact is minimized. Any residual artifact may be removed by subtracting averaged null traces.*

Easy Set-Up

The stepper mechanism is compact, lightweight, and free of either mechanical or electrical noise. The mechanism connects to the control box with a 2 meter shielded cable and is provided with a mounting rod for attachment to a manipulator. Manifolds can support 2, 4 or 6 inputs depending on the experiment. Solutions flow from reservoirs to the manifold through PE-50 tubing and PE-10 tubing is used to connect the manifold outputs to the glass tubes. Micromanipulator and magnetic base is not included.