Platinum-Iridium Bipolar Electrodes, Heat Treated Tapered Tip (MicroProbes)

Description

Platinum-Iridium alloy is considered by many to be the “gold standard” for chronic recording and microstimulation due to its excellent electrochemical and mechanical characteristics.

Advantages

Disadvantages

Platinum-Iridium possesses lower concomitant impedance, higher charge transfer capacity, and improved electrochemical stability compared to tungsten and stainless steel.
Offers excellent and versatile microstimulation performance, allowing safe stimulation to be performed with small probe sizes.
Iridium content of alloy greatly improves mechanical hardness and stiffness, providing electrodes with a degree of bend resistance that approaches tungsten.

Greater cost than tungsten and eligoy or stainless steel, making it less appropriate for acute recording or non-intensive chronic recording.
Can be vulnerable to corrosion and dissolution with some intensive stimulation protocols.

These bipolar microelectrodes of MicroProbes are also available in Tungsten and Elgiloy (an alloy similar to stainless steel). Each electrode is etched to a fine taper and tipped using a proprietary process to a specific impedance value. We offer a variety of different tip alternatives for those that prefer a specialized electrode profile for their research. There are four different tip profiles are also available to further fine-tune your electrode selection to your particular application. The tip selection can provide subtle yet important changes to the performance of the electrode, as described below. It is recommended that first time users consider experimenting with different tip profiles to determine which works best for their recording or stimulation protocols.

Stereotrodes are excellent for bipolar stimulation studies where the current injection needs to be confined to a small localized part of the neural tissue. They have also been used for enhanced isolation of single neural elements by simultaneous recordings of multiple units on two closely spaced microelectrodes. The tip spacing is typically equal to the diameter of the electrode shaft, however, they can be specified to greater separations in most instances.

As an alternative you may consider choosing monopolar electrodes with a thin Paryclene-C coating or with Polymide tubing for insulation, or concentric electrodes.

Stereotrodes (Bipolar Electrodes), Platinum-Iridium, Heat Treated Tapered Tip
(75 µm × 2")

Item	Length	Outside Diameter	Tip Separation	Impedance	Applications	Pkg of 10
PI2ST30.1H3	51 mm	0.216 mm	75 µm	0.1 MΩ	Multi Unit record. & Stim.
PI2ST30.5H3	51 mm	0.216 mm	75 µm	0.5 MΩ	Single & multiunit rec. & stim.
PI2ST31.0H3	51 mm	0.216 mm	75 µm	1.0 MΩ	Single & multiunit rec. & stim.
PI2ST31.5H3	51 mm	0.216 mm	75 µm	1.5 MΩ	Single & multiunit rec. & stim.
PI2ST32.0H3	51 mm	0.216 mm	75 µm	2.0 MΩ	Greater Selectivity & Micro. Stim.
PI2ST33.0H3	51 mm	0.216 mm	75 µm	3.0 MΩ	Greater Selectivity & Micro. Stim.

Stereotrodes (Bipolar Electrodes), Platinum-Iridium, Heat Treated Tapered Tip
(125 µm × 2")

Item	Length	Outside Diameter	Tip Separation	Impedance	Applications	Pkg of 10
PI2ST30.1H5	51 mm	0.356 mm	125 µm	0.1 MΩ	Multi Unit record. & Stim.
PI2ST30.5H5	51 mm	0.356 mm	125 µm	0.5 MΩ	Single & multiunit rec. & stim.
PI2ST31.0H5	51 mm	0.356 mm	125 µm	1.0 MΩ	Single & multiunit rec. & stim.
PI2ST31.5H5	51 mm	0.356 mm	125 µm	1.5 MΩ	Single & multiunit rec. & stim.
PI2ST32.0H5	51 mm	0.356 mm	125 µm	2.0 MΩ	Greater Selectivity & Micro. Stim.

Stereotrodes (Bipolar Electrodes), Platinum-Iridium, Heat Treated Tapered Tip
(225 µm × 2")

Item	Length	Outside Diameter	Tip Separation	Impedance	Applications	Pkg of 10
PI2ST30.1H10	51 mm	0.560 mm	225 µm	0.1 MΩ	Multi Unit record. & Stim.
PI2ST30.5H10	51 mm	0.560 mm	225 µm	0.5 MΩ	Single & multiunit rec. & stim.
PI2ST31.0H10	51 mm	0.560 mm	225 µm	1.0 MΩ	Single & multiunit rec. & stim.
PI2ST31.5H10	51 mm	0.560 mm	225 µm	1.5 MΩ	Single & multiunit rec. & stim.
PI2ST32.0H10	51 mm	0.560 mm	225 µm	2.0 MΩ	Greater Selectivity & Micro. Stim.

Common Tip Profiles:

Schematic of Standard Tip — **A - STANDARD TIP PROFILE**
The standard tip profile features a sharp yet robust point that offers versatile performance and an effective balance between penetration and durability.

Schematic of Blunted Tip — **B - BLUNTED TIP PROFILE**
The blunted electrodes are engineered to have a more rounded, bullet-shaped tip. For many applications the blunted tip can offer superior stimulation performance.

Schematic of Heat Treated Tapered Tip — **H - HEAT TREATED TAPERED TIP PROFILE**
The heat-treated electrodes are intended for those investigators who must penetrate their probes through tough membranes, such as the dura mater of larger mammals.

Schematic of Extra Fine Tip — **F - EXTRA FINE TIP PROFILE**
The extra-fine tip profile features a significantly sharper taper as well as a thinner insulation layer. Available in Tungsten only.

Also see:

Selecting the Optimum Electrode Configuration