Comparison Of Microinjectors

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WPI Microinjectors use carefully regulated air pres­sure for injecting cells with fluid. Injected volumes range from picoliters to nanoliters. The port supplies positive pressure for high-pressure ejection. The pressure port maintains a low positive “compensation” pressure to the injecting pipette between injection pulses to prevent fluid up­take through capillary action.

Timing, injection pressure and compensation pressure are adjusted inde­pen­dent­ly using the touch screen interface. Time intervals can range from 2 seconds down to 10 ms or less, depending on the injection pressure setting. The injection pressure interval is triggered by using a foot switch or a computer-controlled TTL pulse (MICRO-ePUMP uses only a foot switch). 

The WPI Microinjectors are designed to inject very small quantities of fluids, such as drugs, into cells or small organelles. Pressure injection is an especially useful alternative to electroionophoresis, since it does not mandate the use of charged ions. Two different positive pressures may be applied–one for ejection at high pressure and a second, lower pressure to prevent back filling of the pipette by capillary action. 

The WPI Microinjectors offers separate regulated compensation (back filling prevention) and ejection pres-sures with a precision timing circuit that switches from injection pressure to compensation pressure automati-cal­ly.

WPI’s MICRO-ePORE^TM Pinpoint Cell Penetrator technology is embedded inside the MICRO-ePUMP. When the researcher enables the The MICRO-ePORE^TM, it delivers a highly localized voltage signal to a targeted injection site to facilitate penetration with minimal trauma. The researcher determines the amplitude and frequency of the signal that best suits the application. The signal originates in the control box, and it is transmitted through the electrode interface cable to the microelectrode holder. A silver wire is used to transmit the signal into the electrically conductive substance being injected. A reference electrode is used to place the media at 0.0 V potential with reference to the generated voltage.
The MICRO-ePUMP offers separate regulated compensation (back filling prevention) and injection pressures with a precision timing circuit that switches from injection pressure to compensation pressure au­to­mat­i­cal­ly.

System components