Perfusion Fast-Step (SF-77B)
A simple but highly effective delivery device for stimulus solutions used in a variety of patch clamp and other electrophysiology applications.
- Solution stimulus delivery for patch clamp and other electrophysiology studies
- Solution changes in milliseconds
- Minimal flow turbulence
- No switching through intervening solutions
- Manual or automatic step control (digital or analog)
- Modest cost and easy maintenance
- Use with most chambers or culture dishes
The SF-77B is a simple but highly effective stimulus solution delivery device for use in a variety of patch clamp and electrophysiology studies. Control and test solutions flow continuously through adjacent stimulus delivery tubes and a stepper mechanism selects which tube is directed at the preparation. The rapid response and nominal hysteresis of the stepper mechanism allows for very fast switching times. Complete solution changes are typically achieved within 20 msec for a large 700 mm step and times are significantly shortened as the step size is decreased.
Multiple Solution Studies
In the standard configuration, up to six different solutions are connected to a single input manifold which in turn is connected to one of three square glass stimulus ports. The three stimulus port design is superior to a two-port design in that complex solution exchange protocols can be brought to bear on the sample under study. Since the complete system is designed to accommodate three manifolds (one for each stimulus port) and each manifold can accommodate up to 6 feed lines, it is possible to immediately select between 18 different input solutions.
- Solution changes between stimulus ports occur within milliseconds
- Changes between solutions connected to individual port occur within 5 secs
- Entirely new solutions can be added into any port with a waiting time of no more than 30 seconds
- Cell is never required to pass through intervening solutions to get from control to test solution
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 byte word to the TTL input on the instrument rear panel.
Square Glass Stimulus Ports
The square glass tubes used for solution delivery significantly reduces mixing turbulence between solution flows allowing the SF-77B to be used for studies with both membrane patches and whole cells, even when the cells are not fixed to a substrate.
The design of the SF-77B permits the use of various size glass tubing for perfusion delivery.
SF-77B Standard System (0.7 mm ID tubes):
This standard system is shipped with 3SG700-5 single-walled 3-barrel glass tubing which eliminates the need to glue individual barrels together. Spacing between barrels is 0.7 mm and step speed between adjacent barrels is typically 20 msec. Single barrel SG800-5 tubes (up to 5) can be used with the same holder.
SF-77B/5M Standard System with 5 tubes (0.7 mm ID tubes):
This is the same package as the standard system except that the manifold bracket and tube holder have been extended to accept 5 single tubes and associated perfusion lines. The individual tubes can be glued together to make a larger assembly, if desired. Spacing between barrels is 0.6 mm and step speed between adjacent barrels is typically less than 20 msec. Also included are four (4) 6-to-1 MM Series manifolds and one (1) 2-to-1 MM Series manifold.
Large Tube System (1.0 mm ID tubes) Larger stimulus ports are required when using the SF-77B 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.
1 msec Stepping With Theta Tubing The SF-77B has been successfully tested using theta style capillary tubing with a step speed of 1 msec between adjacent barrels. Standard 2 mm diameter theta tubing is pulled to a tip diameter of 300 um with a spacing of 100 um between barrels. In this design, placement of the pipette tip is critical due to the smaller perfusion stream. Since mechanical artifacts can be evident when using these small step sizes the motor drive voltage is adjustable at the rear panel.
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.
We designed the VC-6M to accompany the SF-77B stepper. It conveniently fits inside a Faraday enclosure (e.g. FC-0, FC-1, FC-2) and is remotely controlled with the VC-6 controller. When purchased with the SF-77B, the complete package is discounted. These Fast-Step Systems are supplies with one 2 to 1 and two 6 to 1 manifolds. Other manifolds are available separately.
|Number of Steps||1 to 7 (2 to 8 positions)|
|Step Size||Adjustable from 100 µm to 1.5 mm in 100 µm increments, with STEPS/POSITION switch|
|Step Speed||Typically 20 msec for 700 µm step|
|Manual||8 positions with POSITION selector|
|Analog Signal||5 positions with voltage levels 0-4 V, 1V per step|
|Digital Signal||8 positions with 3 byte TTL signal|
|Max. Stepped Range||12.5 mm|
|Mounting Handle||6.3 mm X 10 cm (D x L)|
|Stepper Weight||110.5 g (including handle)|
Three manifolds supplied
MM series for SF-77B and SF-77BST
ML series with SF-77 BLT
Manifolds have 2, 4 or 6 inputs
One two input and two six input manifolds are supplied
|MM Series||MM-2, MM-4 and MM-6 manifolds use PE-50 tubing at input and PE-10 tubing at output|
|ML Series||ML-2, ML-4 and ML-6 manifolds use PE-50 tubing at both input and output|
|Solution Flow Rates||Rates measured with solution reservoir height of approx. 60 cm (24 in)|
|With MM Series||100 µL/min|
|With ML Series||1 mL/min|
|Size, H x W x D||6.3 x 14 x 23 cm|
|Power||100 to 130 or 220 to 250 VAC, 50/60 Hz, 10 VA|
|Shipping Weight||2.7 kg|
|Warranty||2 years, parts and labor|