microINJECTOR™ All-Digital Multi-pressure System

MINJ-D:  $3,237.84 - In Stock

Power Options

Computer Connectivity

Needle Holder


For demanding applications that require a full-featured microinjection system, Tritech Research offers the MINJ-D All-Digital Multi-Pressure microINJECTOR™. In basic microinjection, a hollow needle with a microscopic tip is filled with a liquid, poked into a target, and then temporarily pressurized so as to inject some of the liquid into the target. The variables that determine the amount injected are pressure, time, viscosity of the liquid, and diameter of the needle opening. A simple, practical system for accomplishing this is our MINJ-1 microINJECTOR™ (standard model). While the MINJ-1, and its line of accessories, help many scientists breeze through their microinjections, some experiments and procedures require a higher level of sophistication, accuracy, and reproducibility. In basic microinjection, the needle is either at a user-set pressure when injecting, or at atmospheric pressure when not injecting. In some cases, backflow of cytoplasm or medium into the needle can be problematic. For these cases, a lower "holding pressure" that is lower than the injecting pressure, but higher than atmospheric pressure is useful between injections. A holding pressure can also reduce needle clogging. No matter how careful a person is, needles occasionally do clog. For these cases, a short blast of a "clearing pressure," higher than the normal injection pressure, is useful to unclog the needles. The MINJ-D employs a user-friendly microprocessor to digitally synthesize injecting, holding and clearing pressures, as well as injection durations reproducibly. Using a simple "Menu" button, and Up and Down buttons, anyone can set the pressures and the injection duration in seconds. It's so intuitive, you won't have to read the directions! Here are the key features and specifications of the Digital microINJECTOR™:
  • Most compact on the market
    6" x 7" x 3" and weighs under 2 lbs.
    (15cm x 17cm x 7cm and weighs under 1 kg)
  • Fast response time between pressures (~100 milliseconds)
  • Simple 3-button control
  • Digital display with backlight for easy reading
  • Microprocessor accuracy
  • Foot pedal included for hands-free injection control
  • Pressure range (applies to each of holding, injecting and clearing pressures): 0 - 100 psi
  • Programmable Injection Duration: 0.1 - 999.0 seconds
  • Built-in Vacuum Generator can be used to front-fill needles by aspiration
  • Manual Injection Mode
  • Injection Data-logging Port for optional computer interface
  • Injection Control Port for optional computer control

The MINJ-D can be attached directly to a laboratory compressed air jet or attached to a compressed Nitrogen cylinder using a pressure regulator such as our TREG-N2.  The system is designed to use a minimum of gas, so even a small cylinder may last for months or years. When ordering, please let us know if you intend to attach your injector to a compressed gas source or an in-house air jet, so that we can provide you with the proper fittings for attachment.

The output of the microINJECTOR needs to be coupled to something. For example, if you're using glass microcapillary needles, our MINJ-4 microINJECTOR™ Brass Straight-Arm Needle Holder will do the job cost-effectively.

A special version, the MINJ-4FEM, is designed for those that prefer to use Eppendorf® prepulled Femtotips® (that screw on) instead of our own lower-cost MINJ-PP prepulled needles that are compatible with our standard MINJ-4.

Another special version, the MINJ-4SLIP, is designed for those who prefer to use SlipTip® and Luer-Lok® Needles (that push or twist on) instead of our MINJ-PP glass needles.


Q: What is the pressure resolution of the microINJECTOR™?
A: The MINJ-D is capable of pressure control in increments of 1 psi or 1 kPa (6 kPa 1 psi), depending on which unit mode you choose.

Q: How much input pressure should be supplied to the MINJ-D via my regulator when using a lab air jet or nitrogen tank as a pressure source?
A: First, never exceed 80 psi (550 kPa), or you may damage the unit or create an unsafe situation!

For the best control, you should set the regulator just a little higher than the highest pressure that you need to deliver. You could start with 50 psi (345 kPa) input and then use the menus to find the best injection pressure (and possibly a clearing pressure that is higher than the normal injection pressure). If you find, for example, that your useful pressures are all under 20 psi (140 kPa), and that the unit is overshooting or not hitting/maintaining the pressures as consistently as you would like, then you can lower the input pressure to 25 psi (175 kPa), and it will be more stable at lower pressures.

Q: Can I still use the MINJ-D with my laboratory compressed air jet or compressor if it delivers greater than 80 psi (550 kPa)?
A: The MINJ-D requires input pressure between 25 psi (175 kPa) and 80 psi (550 kPa). If your lab air jet or compressor might deliver pressure above 80 psi, you can order a low-pressure regulator with a quick connect at the input and output to reduce and stabilize the input pressure. You can order these from us, so contact us to order the correct model. Please note that opening an air jet port only slightly or restricting the flow does not lower the pressure in a closed system, it only slows down how long it takes to get to the full pressure; a pressure regulator is needed to lower the pressure.

† These are our list prices. If you are paying with an Institutional Purchase Order or by check, you qualify for a 7.5% discount. Click here to change your payment method and see the lower prices.