MED64 System: MED probe- 64 Planar Microelectrodes

MED Probes

The standard MED probe has 64 planar microelectrodes arranged in an 8 x 8 grid embedded in the center of a transparent glass plate. Four models with inter-electrode spacings of 100, 150, 300, and 450 µm enable measurements of fine detail from small regions to larger scale interactions across regions. Each electrode is 50 µm x 50 µm in size for 150, 300, and 450 µm spacing configuration and 20µm x 20 µm for 100 µm spacing configuration. Special arrangements are available with Hexagonal pattern, Hippocampal pattern, and 2-4x8 pattern.

The micro planner electrodes patterened on the MED probe are coated with platinum black which has a very jagged surface and effectively increase the surface area of each electrode 200 times. This platinum black technology decreases the impedance to 7-10 k ohm tycpially (at 1 KHz), which in turn has the following benefits;

1) Low noise (The MED64 system does not require a special shielded enviroment but can be operated on a lab bench.)
2) High Signal to Noise ratio-----Easy to acquie signals even from acute slices.
3) Low stiulus artifacts. Higher current stimuatlion (e.g. 200 uA) can also be applied.
4) No blocking pre-amplifier required on connector means that the unit can be used with long cables and placed in an incubator for long term studies.
5) It is possible to acqurie slow-wave signlas such as fEPSP and even signals from smooth muscle tissue (around 0.1 Hz) as well as high-frequency signlas such as spikes.

Close-up views of electrodes surface

Impedance of Pt. black electrode on the MED probe (red) compared with the completely flat electrode (blue)

Download Probe Specifications

Substrate

Glass substrate

50 x 50 x 0.7 mm

Glass cylindrical chamber

ID=22, OD=25 mm

Conducting layer

Indium tin oxide (ITO) (0.15 µm)

Insulation layer

Polyacrylamide (1.4 µm)

Recording/stimulating electrode

Number of electrodes

64 (61 for MED-2H###)

Material

ITO + Platinum Black

Size

50 x 50 µm
20 x 20 µm (MED-P210#)
Diameter 20 µm (MED-P2H07#)
Diameter 50 µm (MED-P5001# & P5002#)

Impedance

<22 k ohm (Typical: 7 k hom) (MED-P5####)
<30 k ohm (Typical: 10 k ohm) (MED-P2####)
(1kHz, 50 mV applied sinusoidal wave)

Maximum voltage

1 V

Maximum current

200 µA, 0.1 msec

Reference electrodes

Number of electrodes

Material

ITO + Platinum Black

Size

200 x 200 µm
Diameter 100 µm x 4 (MED-P2H07#, MED-P5001#)

Impedance

<2.2 k ohm (1kHz, 50mV sinusoidal wave)

(1) Standard 8x8 array

Available in two chamber depth and four inter-electrode spacings

Parts number	Array size	Electrode size	Interpolar Distance	Reference	Chamber Depth
MED-P2105	0.7x0.7mm	20 µm	100 µm	8.5 mm	5 mm
MED-P210A	0.7x0.7mm	20 µm	100 µm	8.5 mm	10 mm
MED-P5155	1 x 1 mm	50 µm	150 µm	8.5 mm	5 mm
MED-P515A	1 x 1 mm	50 µm	150 µm	8.5 mm	10 mm
MED-P5305	2 x 2 mm	50 µm	300 µm	9.2 mm	5 mm
MED-P530A	2 x 2 mm	50 µm	300 µm	9.2 mm	10 mm
MED-P5455	3 x 3 mm	50 µm	450 µm	10.2 mm	5 mm
MED-P545A	3 x 3 mm	50 µm	450 µm	10.2 mm	10 mm

*Minimum order quantity: 10 pcs

(2) Special arrangement

Hexagonal arrangement (61 electrodes)

Available in two chamber depth and 70 µm inter-electrodes spacing.
Hexagonal array was originally developed in the Pine lab at Caltech (Regehr et al., J. Neurosci. Meth. 1989, 30: 91-106).

Parts number	Electrode size	Interpolar Distance	Reference	Chamber Depth
MED-P2H075	20 µm	70 µm	8.5 mm	5 mm
MED-P2H07A	20 µm	70 µm	8.5 mm	10 mm

*Minimum orde quantity : 10 pcs

DOWNLOAD Arrangement of Hexagonal Array

Hippocampal Pattern Arrays (CA1, CA3, & DG)

Available for Rat hippocampus and Mouse hippocampus.
Hippocampal conformal array was originally developed in the Berger lab and the Tanguay lab at USC (Berger et al., IEEE EMBS Special Issue: Toward Biomimetic Microelectronics as Neural Prostheses, 2005, 24, 30-44., Gholmieh et al., J. Neurosci. Meth. 2006, 152 116-129). The present Hippocampal pattern array was designed by the Kawato lab at the University of Tokyo (Mukai et al., J. Neurochemistry. in press).

Parts number		Electrode size	Interpolar Distance	Reference	Chamber Depth
MED-P50015	For Rat	50 µ m	150 µ m	8.5 mm	5 mm
MED-P5001A	For Rat	50 µ m	150 µ m	8.5 mm	10 mm
MED-P50025	For Mouse	50 µ m	150 µ m	8.5 mm	5 mm
MED-P5002A	For Mouse	50 µ m	150 µ m	8.5 mm	10 mm

* Minimum order quantity: 10 pcs

DOWNLOAD Micrograph on MED-P5001#
DOWNLOAD Arrangement of rat HParray
DOWNLOAD Micrograph on MED-P5002#
DOWNLOAD Arrangement of mouse HP array

NOTE: MATLAB scripts to display data recorded by MED64 Conductor as probe arrangement.

2- 4x8 Array Probe NEW!

The 64 electrodes are patterned in two blocks (32 electrodes, each). It allows you to record from separate areas in a slice.

Parts number Pattern
Electrode size

Interpolar Distance

( smallest)
Distance between electrodes block
Chamber Depth

MED-P50035 2-(4x8)
50 µm

150 µm
12 mm
5 mm

MED-P5003A 2-(4x8)
50 µm

150 µm
12 mm
10 mm
*Minimum order quantity: 10 pcs

Dual-Chamber Probe NEW!

The 64 electrodes are patterened in two separate chambers divided by partition placed in the center of the ring. (32 eleectrodes are patterened in each chamber.) It allows you to record from 2 cultures simultaneously using one MED probe and will speed up your experiment.The probe is availabe in two types of partition-height. (5mm, 10mm)

Parts number	Pattern	Electrode size	Interpolar Distance ( smallest)	Distance between electrodes block	Chamber Depth	Partition Height
MED-P5D15A	2-(4x8)	50 µm	150 µm	12 mm	10 mm	10 mm
MED-P5D15B	2-(4x8)	50 µm	150 µm	12 mm	10 mm	5 mm

*Minimum order quantity: 10 pcs

DOWNLOAD the brochure of Dual-Chamber Probe and 2-4x8 Probe

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