Unique features
√  Fast and automated solution change
√  No dead volume
√  No cross contamination between solutions
√  Compatible with Axon and Heka software

Rapid Solution changer
Change of concentration of ion, neurotransmitters or of all possible sort of ligands to be tested is an important issue in modern patch-clamp recordings. The Bio-Logic Rapid Solution Changer is the simplest and easiest-to-use systems to achieve this goal.
This instrument uses the principle known as "sewer pipes" in which the cell or the tip of the electrode (in excised-patch mode) is positioned close to the output of a capillary. The solution to be assayed is flowing out of the capillary at a moderate flow rate. The cell, being exposed in this stream, very rapidly equilibrates in the perfusion solution.

The fact that all solutions are flowing in individual tubes right to their end eliminates all problems of dead volumes, washing and cross-contaminations between solutions to be assayed. This perfusion principle has been used in many laboratories where it has been proved that it was a very adequate system for solution assays.

Fast and automated solution change :
The solutions to be assayed are driven to the rotating head of the RSC. The solution exchange is performed by a very precise rotation of the RSC head which exposes the patch pipette or the cell to the flow of one of the tubes. Times of rotation from one tube to the adjacent one can be programmed from 2 to 800 ms. The motor is light and vibration free thanks to the disk rotor technology and to the micro step command delivered by the controller. Due to the high number of tubes it is possible to have one tube for every solution to be assayed. As compared to fixed tube devices, the rotating head permits a fast change of the perfusion solution around the patch pipette without any contamination from the previous solution at the time of solution switching.

Flow setting :
The flow is controlled by gravity (The flow of other solutions can be stopped with the optional Valve Array or the solutions can flow simultaneously in the bath outside the range of the pipette). The solutions are simply driven by gravity and the flow rate controlled by the height of the reservoir containing the solutions.

Control of the instrument :
Solution changes and valve/motorized syringe control may be performed:

√  Manually from the front panel of the controller.
√  Automatically using analog pulses generated from a stimulator or a D/A board. (see for example : AN#1 - RSC - Control through Axon software ;  AN#2 - RSC - Control through Heka software)
√  Automatically using a PC computer linked via RS-232 or GPIB (with NI GPIB boards only) and the provided software to edit and download a sequence. The RSC-200 doubles as a stimulator since it can deliver an analog stimulation to the patch-clamp amplifier through a 16-bit D/A converter. This stimulator can be programmed in combination with the solution change by the software.

Description of RSC components
The RSC-200 controller
Front panel functions
√  TUBE : tube selection
√  SPEED : speed of rotation selection (2ms to 800ms)
√  REF (pressed once) : reference tube selection
√  REF (pressed twice) : tube alignment. This function permits to adjust a position for every tube separately.
√  SETUP : set-up informations: head model, control mode,
√  EV OPEN : open electrovalve
√  EV CLOSE : closed electrovalve
√  VHOLDV : hold potential set-up (RSC-200 only)
√  REM./LOC : remote or local control
√  START, STOP : start and stop of sequence execution
√  STATUS : functions status

Rear panel functions
√  ANALOG CONTROL-IN : a signal sent to this input can drive the rotating head and the valve opening.
In this mode only the valve in the active position will be opened. When the signal is detected, the corresponding valve is opened. After a programmable delay [0..200ms], the tube is moved to its corresponding position and the previous valve is closed:

· 0mV: no effect
· 100mV: valve #1, tube #1
· 200mV: valve #2, tube #2
· ...
· 2000mV: valve #20, tube #20, etc.

ANALOG CONTROL-OUT: this output reflects the current tube number and can be recorded, for example, together with a patch signal.

· tube #1: 100mV
· tube #2: 200mV
· tube #3: 300mV
√  TRIGGER IN: A rising TTL edge on this input can be used to synchronize with an external signal.
√  TRIGGER OUT: At this output 4 TTL signals can be controlled by the software
√  ELECTROVALVES: Connection for the valve/motorized syringe sets
√  DTR REMOTE: Remote control output for Bio-Logic DTR recorders
√  ANALOG OUT : stimulation output, +/-10V range; 1mV, 1ms step
√  RS-232: Serial port connection
√  GPIB: GPIB port (with NI GPIB boards only)
√  MOTOR: Motor connection

Electrovalves
The electro valves are an optional device which opens the flow only on the selected tubes. If valves are not used all solutions would flow simultaneously as in the RSC-100 instrument. The set of 9 valves are mounted into their housing. The RSC-200 system can drive up to 36 valves (4 sets of valves). The valves used for RSC-200 are normally closed pinch valves. The valves can be commanded by front panel of the controller or the software. All valves can be programmed to open or close synchronously with a tube position change. More than one valve can be opened at a time, or valves can be opened or closed independently of the head rotation. For example to pre-establish the flow in the next tube to be tested a few seconds before rotation.

Syringe Rack and Rack Holder
Two syringe racks are available:
√  for 10ml syringes (standard), 18mm holes
√  for 50ml syringes (on request), 32mm holes
The most convenient way to hold the reservoir syringes is to use the syringe rack that has been especially designed for this use. The syringe rack can be installed or hanged at the most convenient location in the Faraday cage or set on its holder . One syringe rack can be set on each side of the rack holder, giving a total capacity of 18 syringe reservoirs.

The Head
One of the important features of RSC head is an easy exchange of solution delivering tubing, this eliminates necessity of washing and risks of residual contaminations. Every RSC-200 system is delivered with one head.
The straight head was designed to carry standard capillary glass, OD 1.00mm. This head gives the following advantages:
√  Capillaries can protrude, giving better approach to a cell.
√  The number of capillaries installed is up to the user.
√  Capillaries take minimum space in the cuvette.
√  Easy exchange of capillaries.
√  Easy attachment to the flexible tubing
The head is made of Delrin, reinforced by an internal metal rod, for best shape stability. The outside diameter of the head is manufactured with the highest precision (+/- 10 microns) to give a good reproducibility of the tube positions. The head is equipped with two guiding pins for straight and parallel positioning of capillaries. The capillaries are kept in their position by two O-rings for easy installation and alignment. The capillaries are connected to a short piece of polyethylene tubing, which is connected to larger tubing going through electro valves into the reservoir syringes.

Glass capillaries
The straight head is designed to work with glass capillaries of an outside diameter 1.00mm (Ref: GB 100TF 8P - thin wall with filament, ID=0.78 mm, length: 8cm, fire polished ends).
Other glass brands can also be used.

Flexible tubing
To connect reservoir syringes with capillaries installed on the straight head, two types of tubing are used in standard version (see below for high flow rate set-up).
1) Polyethylene tubing (ID: 0.3, OD: 0.70mm), is inserted into the rear end of the capillary tube. Approximately 10-15cm length is needed. This tubing is used to interface with bigger diameter tubing coming from reservoir syringes and to minimize the load on the rotating head.
2) C-Flex tubing (ID: 0.5mm, OD: 2.1mm, Reference: COLE PARMER #6424-59 ) is used to connect the reservoir syringe with the polyethylene tubing coming out of the capillary glass. C-Flex tubing is well adapted to our electro valves and is much less permeable to air than, for example, silicon tubing.

Stimulator
The RSC-200 is equipped with one stimulator channel (+/-10V, 1mV and 1ms resolution). This stimulation is programmed by the same software as the solution change.

TTL
On the rear panel of the instrument 4 x TTL , independently programmable channels are available. As for the stimulation channel, the TTL pulses are programmed by the same software as the solution change.

Software
The RSC-200 instrument are delivered with a 32-bits Windows software. The software permits the following operations:
√  manual positioning of the head
√  manual opening of the valves
√  resting Vhold setting
√  edit and download of a sequence where the following parameters can be exchanged at each step:
· duration of stay in the active position for a given tube number
· speed of solution change (head rotation)
· choice of electrovalves to be opened/motorized syringes to start (if applicable)
· stimulation pulse level ( range: +/-10V) (RSC-200 only)
· TTL signal activation (4 lines of signal available)
· triggering of other auxiliary instruments
Software compatibility of the RSC-200 V2.00 software was tested sucessfully with WindowsXP Pro 32-bits, Windows Vista Business 32-bits, and Windows7 64-bits with the following configuration:
√  USB to RS-232C converter (Belkin F5U103)
√  USB to GPIB converter (National Instruments GPIB-USB-HS - software driver V2.8)

Manipulator
The RSC-200 motor can be mounted, on any 3-axis manual manipulator, providing that the motor will have a mechanically stable fixation. We recommend 2 models of manipulators: UM-3C (with rotation mechanism) (You), M-152 (Narishige).
These manipulators may be delivered with magnetic stands.