Injection
Computer assisted microinjection requires highly accurate positioning and reproducibility.
Therefore, companies like e.g. AIS 2 have decided to use a micromanipulation system made by Luigs & Neumann.
In the field of electrophysiology, Luigs & Neumann has a worldwide reputation for superior micromanipulators, featuring both high precision and high stability
Injection of cells with dense and sticky membranes - like primary neurons - requires a very fast penetration.
Often the stepper motor driven injection axis is too slow.
In this case for the injection movement one has the option to use a piezo drive piggy back mounted to the injection axis.
The micromanipulation system mounts to any inverted Zeiss microscope.
The newest setup for the "Axiovert" 200 comes as a compact unit, which just replaces the regular stage plate
As soon as the elongation of the piezo element takes place almost free of delay, a rapid in and out movement of the capillary is achieved.
Together with the field selection features of the control program optimum conditions for microinjections of neurons are provided.
Principle of Operation
Today piezo elements are very abundant in technical devices.
The piezo effect - generation of electrical charge when pulling or pressing a quartz crystal, - is used in digital scales, microphones, and a variety of mechanical and pressure sensors.
The reverse piezo effect - elongation of a crystal when charging it, - is used in all quartz stabilized oscillators as in wrist watches or computers, in beepers, in miniature speakers, and in micromanipulation devices.
Piezo comes from the Greek language and means push or press.
If a crystal consisting of ions, which possesses a polar axis, is deformed, it gets polarized.
Examples are Quartz or PZT (Lead Zirconium Titinate) in the inside of the crystal dipole momentums can form or existing momentums can change.
Following this, an electrical charge can be measured on its surface (piezo electricity).
Reversely, charging the crystal results in its deformation.
The angle of the injection axis can be adjusted between 30° and 55°.
This allows for the use of high numerical aperture condensers (e.g. Carl Zeiss LD Condenser 0.55 mot) with a working distance of less than 30 mm.
The patented construction of the adjustable nut and screw system of all Luigs & Neumann axes reduce backlash to virtually zero.
This is especially important when focussing with the stage Z-axis to bring cells back precisely into injection level.
Essential Microscope Components for Microinjection
Component list
- Microscope stand
- Binocular tube
- Halogen lamp
- Holder for illumination equipment
- Lens for overview, e.g. Zeiss A-Plan 5x
- Lens for microinjection, e.g. Zeiss A-Plan 32x, Ph1
- Condenser 0.3 with bright field and phase contrast
- C-mount video camera port
- C-mount adapter 1x
Of course, if required by application, the microscope can be equipped with fluorescence, additional lenses, additional cameras for high definition imaging, etc.
When the "Axiovert" 200 is used, it must be ordered with the RS232 Interface board (Carl Zeiss part No.: 000000-1015-381) build into the microscope, to make its lens position encoding available.
The motorized version "Axiovert" 200 M already contains this board.
The system adapts only to inverted microscopes made by Carl Zeiss.
In our opinion Zeiss microscopes are best suited for this particular task.
The new Axiovert 200, especially the fully motorized version 200M, makes microinjection as easy as never before.
It also offers the opportunity to upgrade the system to an imaging workstation where injected cells can be monitored over longer times.
All microscope controls can be accessed through software available for this task.
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