Plextrode® U-Probe

U-Probes are now available with thinner probe diameters and thinner reinforcement tubes. The 16- and 24-channel U-Probes now come in 185 µm and 210 µm outer diameters, respectively. The thin U-Probes with 15 μm diameter platinum/iridium electrode sites have been proven to be excellent recording probes for both single units and field potentials. Larger diameter electrode sites are also available.

The new, thin 460 μm diameter reinforcement tubes result in less space between the the thin section of the UProbe and the guide tube, for increased stability while pushing through dura.

All UProbes can be fitted with either fiber optic lines or fluid channels for drug delivery. The location of the optic fiber and fluid capillary along the shaft of the UProbe is user defined.



The U-Probe is a customizable, robust, multi-use, multi-site linear electrode. Flexibility in the manufacturing process allows for different electrode site arrangements and spacing, as well as optional fluid delivery channels or fiber-optic stimulation lines intermixed within the recording sites.

The precise linear arrangement of the electrode sites enables current source density analysis of the field potential signals as recorded from laminar neural structures. The small electrode site diameter (15 µm - 20 µm) enables single unit recording. Special etching of the electrode surface results in impedances of only 275 kOhm (+/- 50 kOhm) for the 15 µm diameter sites.

Electrode Configurations

 

 

 

 

 

8 Single electrodes
16 Single electrodes
24 Single electrodes


4 Stereotrodes
8 Stereotrodes
16 Stereotrodes


2 Tetrodes
4 Tetrodes
6 Tetrodes

 

With Optic Fiber

see: Fiber Optic U-Probe (above)

With Fluid Channels

4 fluid channels,
single electrode configuration

4 fluid channels,
stereotrode configuration

4 fluid channels,
tetrode configuration

1 fluid channel,
8-channel probe with fluid channel - only has 7 active recording sites

 

Brain Slice Configuration

The U-Probe can be bent at a 45 degree angle to record from brain slices.

 

The U-Probe is handmade and very customizable. Please contact Plexon at info@plexon.com if you don't find the configuration or feature you need.

 

 

  • Durable, multi-use, multi-site linear probe
  • Guaranteed for a minimum of 30 penetrations through properly prepared dura
  • 8, 16, or 24 electrode sites embedded in a stainless steel needle
  • 15 or 20 μm platinum/iridium electrode site diameter, HML insulated (polyimide), secured in medical-grade epoxy
  • User-defined, inter-electrode spacing (see Technical Specs for options)
  • Available in single, stereotrode, and tetrode configurations (50 μm electrode spacing within stereotrode or tetrode configurations)
  • Optional fiber optic channels for optogenetic stimulation
  • Up to four optional glass capillary channels for fluid delivery
  • Probe diameter depends on number of recording sites and fluid/opto channels (see technical specs)
  • Contact Plexon at info@plexon.com for information on fiber-optic stimulation lines

 

Thinner reinforcement tubes now available

The standard UProbes have typically been fitted with a 640 μm outer diameter reinforcement tube. Now, 460 μm diameter reinforcement tubes are also available. The thinner reinforcement tubes enable the use of guide tubes with smaller inner diameters. Less space between the thin section of the UProbe and the guide tube results in more stability while pushing through dura and better recording performance after entering the brain.

 

UProbe thin reinforcement tube


      Thinner 460 μm OD reinforcement tube                                                                Original 640 μm OD reinforcement tube

 

Recommended UProbe and guide tube lengths for pushing through dura

The UProbe is capabile of penetrating properly conditioned dura when properly positioned within a guide tube. Since the thin section of the UProbe (typically 185 µm or 210 µm OD) is quite flexible, it is recommended to use UProbes and guide tubes of specific lengths so that the reinforcmenet tube enters the guide tube before the thin section of the UProbe contacts the dura.

Using UProbes and guide tubes of the correct lengths will

  1. minimize the likelihood of damaging the probe while penetrating the dura
  2. improve the stability of the Uprobe as it pushes through the dura
  3. improve the quality of recordings at superficial cortical layers

 

Correct Insertion Method

                                        Recommend UProbe and guide tube lengths for
                                              optimal stability and recording quality

 

The UProbe total length and reinforement tube length are customizable and made-to-order. Contact your Plexon sales representative for advice on which length UProbe to use for optimal UProbe stability and performance.


# of Recording Sites # of Fluid Channels Electrode Diameter (µm) Probe Diameter (µm)
8 1 20 230
16 0 15 185
16 1 15 360
16 2 15 420
24 0 15 210
24 1-2 15 420
24 3-4 15 500

* 16- and 24-channel U-Probes can also be configured with 20µm or 25µm electrode wire.

Feature Standard Spec (approximate lead-time 4 -6 week Optional Spec (approximate lead-time 7 - 9 week)
Channel Count 8, 16, or 24 recording sites  
Electrode Configuration Single Stereotrode or Tetrode
Electrode Impedance (for 15μm diameter site)
 275 (+/- 50) kOhms @ 1kHz  
Electrode Site Diameter 15μm
Inter-electrode Spacing 150 - 200μm 50, 100, 150, 200, 250, 300, 400 500μm
Electrode Spacing within a Stereotrode or Tetrode group 50μm  
Distance to First Electrode 500μm 200 - 5000μm
Tip Angle and Shape 30 degree angle, linear taper

(i) 20 - 60 degree angle, linear taper
(ii) rounded, hemispherical
Probe Length 100mm (30mm of reinforcement tube, 70mm of probe) 10 - 130mm
Reinforcement Tube Length 30mm >30mm
Reinforcement Tube Diameter 460μm or 640μm  
Probe Diameter See Table above (probe diameter depends on number of channels)  
Fluid/Fiber Optic Channel Count 0, 1, 2, 3, 4  
Fluid/Fiber Optic Channel Location At midway point of exposed electrode sites Any location
Fluid Channel Diameter 40μm glass capilary
  
Connector interface

8-channel: 10-pin Omnetics (0.050" pitch) connector< br>16-channel: 20-pin Omnetics (0.050" pitch) connector
24-channel: 36-pin nano Omnetics (0.025" pitch) connector
(see pin-out specifications in Related Documents tab under Documentation)
Bend Angle in Brain Slice 45 degree angle, 20mm from tip User defined

 

 

 

 Tip Angle

 

Janus Probe Specifications:

  • Available in 8, 16 & 24-channel versions
  • User defined electrode spacing on two sides of probe shaft
  • User defined spacing from probe tip to first "group" of electrodes
  • User defined probe length

 

Janus probe

Fiber Optic U-Probe Specifications:

  • 16 electrode sites (15 um) in a 210 um tube
  • 3 - 50 cm length of cable
  • Any connector interface to stimulating source

 

fiber optic u-probe

 

 


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