Basics of microiontophoresis
Microiontophoresis is the technique whereby ions or charged molecules can be ejected in very small amounts from solutions contained in glass micropipettes. Microiontophoresis is most often used for (1) deposition of dyes or neural transport tracers for subsequent histological examination or for (2) administration of neuroactive compounds (e.g. transmitters, modulators, drugs or hormones) by microiontophoresis to examine their effects on firing parameters of single neurons in vivo.
During an experiment the resistance of an iontophoresis pipette may fluctuate for a variety of reasons (mostly biological). This requires a precision constant current source, or iontophoresis pump as it is popularly called, which using Ohm’s Law automatically maintains a constant current flow through the barrel independently of its resistance. An iontophoresis pump, in compensation to fluctuations in tip resistance, automatically changes the voltage applied to the iontophoresis pipette to produce a constant current set by the experimenter.
For more details, see our white paper: Introduction to the Art of Microiontophoresis.
BAB-501 microampere iontophoresis pump kit
This iontophoresis pump was specifically designed for iontophoretic deposition of neural dyes or transport tracer substances. It provides constant currents up to 20 microampere with either polarity with maximum compliance voltage of +/-500 V. Three modes of operation can be selected: continuous, externally switched or 7s on, 7s off cycles. Requires an external 12 VDC power supply, order separately. See our M1116 international model.
Comes complete with one type 1 iontophoresis cable, 1 mini banana plug and manual.
Union-200 nanoampere iontophoresis pump kit
This precision constant current source permits iontophoretic ejection of electrically charged substances to test their effects on neuronal firing using currents up to +/-500 nA. Between ejection periods, retention currents of opposite polarity can be selected up to +/- 50 nA. The maximum compliance voltage is +/-180 V what is a world record in its class. Output currents can be recorded at a 10 mV/nA conversion rate. It can work together with our Balance unit (M1210, see below) when neutralization of tissue currents is required. Requires an external 12 VDC power supply, order separately. See our M1116 international model.
Sold complete with one type 2 iontophoresis cable, 2 mini banana plugs and manual.
Union balance current unit
Neurons tend to be excited by current when higher than a few tens of nanoamperes are used in a microiontophoresis experiment. A balance unit is used to compensate this effect by producing an algebraic sum of all currents flowing and eject it with opposite polarity so that the net current flow in the tissue will be zero. Our balance unit can work with up to four Union iontophoresis pump at a time. For example, see below (M1220).
The maximum compliance voltage is +/- 180 V with compensation current intensity up to +/- 800 nA. Output currents can be recorded at a 10 mV/nA conversion rate. Requires an external 12 VDC power supply, order separately. See our M1116 international model.
Comes complete with one type 2 iontophoresis cable, 2 mini banana plugs and a manual.
Union minitower: Four Union-200s and one balance current unit
Here we offer a cost-effective combination of 4 Union-200 iontophoresis pumps and 1 balance channel in one kit. This setup is capable of controlling 4 iontophoresis barrels filled with various compounds of interest in studying firing of neurons and 1 balance channel to close out possible artefacts due to current flows. Our Carbostar-7S multibarrel recording/iontophoresis combination CF microelectrodes are recommended for use in conjunction with this system.
Sold complete with 5 type 2 iontophoresis cable, 2 M1116 external power supplies, 3 DC power cable for daisy chaining, 4 BNC to BNC cables, 10 mini banana plugs and a manual. Plug and play simplicity out of the box!
See also our white paper: Introduction to the Art of Microiontophoresis.