Alpha MED Scientific MED64 User manual

MED64 System
(MED64-Basic/Quad II/Allegro)
Manual

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Table of Contents
1. Introduction ……………….. 1
2. Configuration of the MED64 System ……………….. 1
2.1. Part names and functions ……………….. 1
2.1.1. MED64 Main Amplifier ……………….. 1
2.1.2. MED64 Head Amplifier ……………….. 2
2.1.3. Accessories of the MED64 Main Amplifier ……………….. 3
2.1.4. Accessories of the MED64 Head Amplifier ……………….. 3
3. Setup of the MED64 System - procedure common to Basic, Quad II, and Allegro ……………….. 3
3.1. Considerations for the position of devices ……………….. 3
3.2. Power source ……………….. 4
3.3. Setup of the MED64-Basic ……………….. 5
3.3.1. Part names and functions of the MED Connector ……………….. 5
3.3.2. Connections among devices ……………….. 5
3.3.3. Positioning of the terminal of the MED Connector ……………….. 6
3.3.4. Electric shield with aluminum foil ……………….. 6
3.3.5. Preparation for the noise check – attaching the MED Probe ……………….. 7
3.3.6. Maintenance of the MED Connector ……………….. 7
3.4. Setup of the MED64-Quad II ……………….. 9
3.4.1. Part names and functions of the MED Duet Connector ……………….. 9
3.4.2. Connections among devices ……………….. 9
3.4.3. Positioning of the terminal of the MED Duet Connector ……………….. 10
3.4.4. Preparation for the noise check – attaching the MED Probe16 ……………….. 10
3.4.5. Maintenance of the MED Duet Connector ……………….. 11
3.5. Setup of the MED64-Allegro ……………….. 12
3.5.1. Part names and functions of the MED Multi-well Connector ……………….. 12
3.5.2. Connections among devices ……………….. 12
3.5.3. Positioning of the terminal of the MED Multi-well Connector ……………….. 13
3.5.4. Preparation for the noise check – attaching the MED Multi-well Probe ……………….. 14
3.5.5. Maintenance of the MED Multi-well Connector ……………….. 14
4. Noise check by operating the Mobius - procedure common to Basic, Quad II, and Allegro ……………….. 15
5. Combining with a perfusion system ……………….. 16
5.1. Position of the Minipuls 3 and power supply ……………….. 17
5.2. Installing MED Perfusion Cap Kit to the Minipuls 3 ……………….. 17
5.3. Connection between MED Thermo Connector and MED Perfusion Cap Kit ……………….. 17
5.4. Fixing the droppers to the dropper stand ……………….. 18
5.5. Adjusting the height for the inlet/outlet pipes in the MED Perfusion Cap ……………….. 18
5.6. Connecting the gas tubing to the gas port of MED Perfusion Cap ……………….. 19
5.7. Grounding platinum wire of the MED Perfusion Cap ……………….. 19
5.8. Running the Minipuls 3 ……………….. 19
5.9. Noise check by operating the Mobius ……………….. 19

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6. Abnormal noise ……………….. 19
6.1. Noise check point ……………….. 19
6.2. Noise relating to installation ……………….. 20
6.3. Noise relating to perfusion ……………….. 22
6.4. Identification of cause when a malfunction of the device is suspected ……………….. 23
7. Appendix ……………….. 25
7.1. Specification ……………….. 25
7.1.1. MED64 Main Amplifier [MED-A64MD1A] ……………….. 25
7.1.2. MED64 Head Amplifier [MED-A64HE1S] ……………….. 26
7.1.3. MED Connector ……………….. 27
7.1.4. MED Duet Connector ……………….. 27
7.1.5. MED Multi-well Connector ……………….. 27
7.1.6 Data Acquisition PC ……………….. 27
7.2. Explanation of the technology ……………….. 29
7.2.1. Signal acquisition by the MED64 system ……………….. 29
7.2.2. Electric stimulation by the MED64 system – Applying current to the micro electrode array ……………….. 29
7.2.3. Stimulus artifact and biphasic stimulation ……………….. 30
7.2.4. Stimulus intensity and electrolysis ……………….. 30
7.2.5. About the stimulus interval ……………….. 30

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1. Introduction
◆ The MED64 System is a micro electrode array (MEA) system commercialized for the first time in the world in 1997. Since then,
the MEA system has been widely used in the United States and the EU for basic research in the fields of the central nervous
system and the cardiovascular system. Nowadays, its application to screening for drug discovery is rapidly spreading, thanks to
its highly evaluated excellent operability and efficiency.
◆ The system use a MEA with 64 planar electrodes arrayed in a pattern (MED probe) on a glass substrate. Users can acquire
extracellular potential simply by placing a tissue slice or by culturing cells on these electrodes. Current stimulation can be
applied through any electrode selected by software. Unlike a glass capillary electrode, the MED64 system requires no
troublesome operations to measure spontaneous activity or evoked response and no special training for electrophysiological
experiment is necessary. The system allows for accurate and easy measurements even by unexperienced researchers.
◆ The electrodes are made of platinum black or carbon nanotube with impedance 7 to 10 kΩ, the lowest impedance among
similar products on the market. The system is substantially free from external noise, thanks to its low impedance electrodes. It
needs no special environment/facility for electrophysiological experiment, such as a shield box, and it can be placed on a
laboratory desk for stable, daily measurement with no need for noise elimination.
2. Configuration of the MED64 System
The MED64 System consists of the following units. The number of biological specimens from which simultaneous measurements
can be made depends on the type of the Connector onto which the MED Probe is mounted.
The MED64 Head Amplifier has connection terminals dedicated for all types of Connector, which allows the user to switch the
system easily by changing the type of Connector to be connected. The extracellular potentials detected by the recording electrodes
of the MED Probe are amplified 10 times by the MED64 Head Amplifier and then further amplified (varied) by the MED64 Main
Amplifier before analog to digital conversion. The obtained digital signals are sent through the USB cable to the data acquisition PC
system, where data recording and analysis are performed online using the MED64 Mobius, which is the dedicated MED64 System
control software. (Recorded data can also be analyzed offline.)
MED64 Head Amplifier
MED64 Main Amplifier
Data acquisition PC
Control software
“Mobius”
MED Probe
MED Connector
MED Probe16
MED Duet Connector
MED Multi-well Probe
MED Multi-well Connector
Head stage for MEA
MED64-Basic
MED64-Quad II
MED64-Allegro

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2.1. Part names and functions
2.1.1. MED64 Main Amplifier
【Front】
➊POWER ….. To switch ON/OFF of the power.
【Back】
➊INPUT ….. An analog input terminal to input signals from the MED64 Head Amplifier. It is connected to the OUTPUT of the
MED64 Head Amplifier via the 68-pin SCSI cable.
➋OUTPUT ….. An analog output terminal to connect an external device (MED Feedback Stimulator etc.)
➌DIO 1、2、3 ….. Digital input/output terminal to connect MED64 Multiplexer.
➍F1 STIMULUS OUTPUT ….. An output terminal of stimulus pattern signal from F1 stimulator. It is connected to F1 STIMULUS
INPUT of the MED64 Head Amplifier via the BNC cable.
➎F2 STIMULUS OUTPUT ….. An output terminal of stimulus pattern signal from F2 stimulator. It is connected to F2 STIMULUS
INPUT of the MED64 Head Amplifier via the BNC cable.
➏CONTROL OUTPUT ….. An output terminal of stimulation channel signal. It is connected to CONTROL INPUT of the MED64
Head Amplifier via the round-pin cable.
➐SIGNAL GND ….. A ground terminal to connect a lead for grounding.
➑USB ….. It is connected to a USB terminal of the data acquisition PC via the USB cable.
➒DC INPUT ….. To connect to a power adaptor cord.
2.1.2. MED64 Head Amplifier
【Front】
➊Power ….. To switch ON/OFF of the power.
➋STIMULUS CURRENT ….. The output current is doubled by moving the lever toward x2.
【Back】
❶
❶
❷
➌
➌
➌
❹
❺
❻
❼
❽
❾
❶
❷
❶
❶
❶
❶
❷
➌
❹
❺
❻
❼
❽
❼

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➊INPUT 1-16CH、17-32CH、33-48CH、49-64CH
….. Analog input terminals to input signal from the MED Duet Connectors or the MED Multi-well Connector. Those are connected
to the output terminals of the either via the 20-pin SCSI cable. Keep ➋INPUT opened (unconnected) when connecting the
cables (Do not connect at the same time.)
➋INPUT ….. An analog input terminal to input signal from the MED Connector. It is connected to the output terminal of the MED
Connector via the 68-pin SCSI cable. Keep the all ➊INPUT opened (unconnected) when connecting the cables (Do
not connect at the same time.)
➌OUTPUT ….. An analog output terminal to connect the INPUT terminal of the MED64 Main Amplifier via the 68-pin SCSI cable.
➍F1 STIMULUS INPUT ….. An input terminal of stimulus pattern signal to connect the F1 STIMULUS OUTPUT of the MED64 Main
Amplifier via the BNC cable.
➎F2 STIMULUS INPUT ….. An input terminal of stimulus pattern signal to connect the F2 STIMULUS OUTPUT of the MED64 Main
Amplifier via the BNC cable.
➏CONTROL INPUT ….. An input terminal of stimulation channel signal. It is connected to CONTROL OUTPUT of the MED64 Main
Amplifier via the round-pin cable.
➐SIGNAL GND ….. A ground terminal to connect a lead for grounding.
➑DC INPUT ….. To connect to a power adaptor cord.
2.1.3. Accessories of the MED64 Main Amplifier
➊Power adaptor ➋68-pin SCSI cable (50cm) ➌BNC cable ➍Round-pin cable ➎USB cable
2.1.4. Accessories of the MED64 Head Amplifier
➊Power adaptor
3. Setup of the MED64 System - procedure common to Basic, Quad II, and Allegro
Thanks to the excellent electrode impedance (impedance of 50 µm electrode is 10 kΩ in frequency range 1 kHz) of the MED Probe,
which is the sensor of the MED64 System, the MED64 System offers several technological advantages:
1) Less influence by external noise (hum noise, etc.)
2) Very low Johnson noise (baseline noise) at about several µV
3) The MED Probe/Connector can be installed at a place physically distant from the amplifier (e.g., inside of an incubator with
100% humidity) via a 2 m connection cable, without being affected by noise or attenuation of the signal acquired.
A faraday cage or vibration isolation table that is typically necessary for an electrophysiological experiment is not necessary for the
MED64 System, but the MED64 System should be set up on a stable table without vibrations, such as a laboratory desk. A desk of
about 100 cm width and 75 cm depth is necessary. For the user’s convenience, a larger desk is preferable. The power adaptor
connected to the amplifier, etc., serves as a magnetic field-derived noise source. When the MED64 System is set up on a desk
against a wall, make space for the cord between the wall and the desk and place the adaptor on the floor in order to place the
power adaptor at a distance from the amplifier and other components (the desk must not be fixed to the wall). Alternatively, a space
is necessary to ensure sufficient distance between the MED64 System and the power adaptor.

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3.1. Considerations for the position of devices
Considering the position of the SCSI cable that connects the Input Terminals of the MED64 Head Amplifier and the MED
Connector, place the MED64 Main Amplifier on the MED64 Head Amplifier (not essential). Place the display monitor on the MED64
Main Amplifier with the PC and the power strip arranged on the right or left side and the MED Connector on the opposite side to
provide sufficient space on the MED Connector side so that the user can perform an experiment easily on the MED Connector side.
Do not place the power adaptor or other electronic devices close to the connection terminals on the back of the amplifiers.
- Layout sample 1
- Layout sample 2
Above is an image of the ideal positions of the components. The user can perform an experiment easily when there is a sufficient space
next to or at the back of the laboratory desk with the power strip on the floor (as shown in Layout Sample 2). If the MED64-Quad II is to
be used in combination with four perfusion systems, a larger space will be necessary.
3.2. Power source
Connect all the 3-terminal power plug (MED64 Main Amplifier, MED64 Head Amplifier, data acquisition PC, etc.) to one power strip
connected to a wall outlet with the ground terminal (do not use an outlet on the desktop rack because it is often not grounded
properly). Do not connect devices that are not necessary for the MED64 System to the power strip or to the wall outlet to which
the MED64 System and other components are connected. Place the power cable and the power adaptor at a distance from the
amplifier, the MED Connector and the 68-pin SCSI cable.
Space for cables on the back of the amplifier
MED Connector
Mouse
Keyboard
PC
Display monitor
Power strip (on the PC)
Power adaptor
60 cm
120 cm
Amplifier (front)
Amplifier (back)

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3.3. Setup of the MED64-Basic
3.3.1. Part names and functions of the MED Connector
【Top unit】 【Base plate】 【Accessory】
➊Output terminal ….. To connect to INPUT of the MED64 Head Amplifier via the accessory, the 68-pin SCSI cable.
❷Fixation screw ….. To fix the fitted top unit and the base plate with a MED Probe attached.
❸Contact pin ….. To contact with the MED Probe terminal to read signals.
❹Ground wire with an bagworm clip ….. To connect to a platinum wire with a perfusion cap when a perfusion system is used.
❺68-pin SCSI cable (2 m) ….. A conductive cloth tape and ground wire are wound on the cable.
3.3.2. Connections among devices
➊Connect the INPUT terminal of the MED Main Amplifier and the OUTPUT terminal of the MED Head Amplifier, using the 68-pin
SCSI cable (50 cm).
➋Connect the F1/F2 STIMULUS OUTPUT of the MED64 Main Amplifier and F1/F2 STIMULUS IMPUT of the MED64 Head
Amplifier, using the BNC cables.
➌Connect the CONTROL OUTPUT terminal of the MED64 Main Amplifier and the INPUT terminal of the MED64 Head Amplifier,
using the round-pin cable.
❶
❷
❷
❸
❹
❺
❻
❼
❼
Display monitor
PC
MED64 Head Amplifier
MED64 Main Amplifier
❶
❹
❺
❷
❷
❸

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➍Connect the output terminal of the MED Connector and the INPUT terminal of the MED64 Head Amplifier, using 68-pin SCSI
cable.
➎Connect the ground wire wound on the 68-pin SCSI cable to the SIGNAL GND terminal of the MED64 Head Amplifier.
➏Connect the USB port (type-B) of the MED64 Head Amplifier and the USB port (type-A) of the data acquisition PC (USB2.0 is
preferable), using the USB cable
➐Connect the power adaptor cables to both amplifiers.
Note1: The 68-pin SCSI cable is wound with a conductive cloth tape and an uncoated lead is wound on it. If the other side of the
lead is free, the conductive cloth tape may serve as an antenna that collects electric noise and may cause noise. Make sure
that the other side of the lead is connected to the SIGNAL GND terminal of the MED64 Head Amplifier (to use the
conductive cloth tape as an electric shield).
Note2: In order to prevent noise, use the SIGNAL GND terminal of the MED64 Head Amplifier for single-point grounding when
the peripheral devices are grounded.
Loosen the screw of SIGNAL GND terminal to lead the ground wire into the hole (left), then thighten to fix it (right) 。
3.3.3. Positioning of the terminal of the MED Connector
Place the MED Connector with its output terminal and the 68-pin SCSI cable on the right side. In this position, the left top of the
MED Probe is assigned to ch 1 and the right bottom is assigned to ch 64. The orientation of the MED Probe is important because
the electrode number of the MED Probe is defined by the contact pins of the MED Connector.
Correspondence between the contact pin of the MED Connector and the electrode number: correspondence from the contact surface side with
the output terminal on the right (left panel) and correspondence with the MED probe terminal (right panel). R indicates the reference electrode.
ch 1
ch 64
ch 56
ch 8
R1
R2
R3
R4
ch 1
ch 64
ch 56
ch 8

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Correspondence between the MED Connector output terminal and the electrode number. R indicates the reference electrode.
3.3.4. Electric shield with aluminum foil
If a noise check reveals that external electric noise is affecting the MED Connector, the noise may be avoided by placing a sheet of
aluminum foil under the MED Connector and using a lead to connect the aluminum foil sheet and the SIGNAL GND terminal of
the MED64 Head Amplifier for grounding.
A sheet of aluminum foil serves as an electric shield by grounding. Magnetic field-derived noise cannot be prevented by an electric shield.
Note: Although the MED Connector is made from aluminum, its surface is coated and insulated from the aluminum foil. Make
sure that the aluminum foil is grounded to the SIGNAL GND terminal of the MED64 Head Amplifier when a sheet of
aluminum foil is placed under the MED Connector, even if the baseline noise level is within an acceptable range. Without
grounding, the aluminum foil serves as an antenna to collect electric noise and may generate unexpected noise.
MED64-Basic after setup. In this example, the laptop PC is used for a data acquisition PC system.
3.3.5. Preparation for the noise check – attaching the MED Probe
Loosen the fixation screw of the MED Connector to remove the top unit.
Fixation
screw
Top unit
Base plate
Fixation
screw