Microinjection refers to the process of using a fine tipped needle to
insert substances at a microscopic level into a cell or the intercellular space. It is a simple
mechanical process in which a needle roughly 0.5 to 5 micrometers in
diameter penetrates the cell membrane and/or the nuclear envelope or simply into a tissue. The
desired contents are then injected into the desired sub-cellular, cellular, or intercellular
compartment and the needle is removed. Microinjection is normally
performed under a specialized microscope with the aid of a
micromanipulator which allows for small movement under high
AREAS OF APPLICATION AND USE
Microinjection is frequently used in genetic engineering and
transgenetics to insert genetic material into single cells.
Microinjection can also be used in basic genetics research, in the
cloning of organisms, and in the study of cell biology and viruses.
Common clinical applications include In Vitro Fertilization (IVF) and
Intracytoplasmic Sperm Injection (ICSI) to help achieve fertilization
for couples with severe male factor infertility, and for ophthalmology
procedures like Retinal Pigment Epithelial (RPE) and Intra Ocular (IO)
In basic microinjection, a hollow needle with a microscopic tip is
filled with a liquid, inserted into a target, and then temporarily
pressurized so as to inject the desired fluid into the target. The two
broad areas of microinjectors are Analog and Digital Pressure-type, vs.
Positive-displacement and syringe-type injectors all of which have a broad range of features
and price ranges to assist you in your research. The
variables that determine the amount injected with pressure-type injectors are pressure, time,
viscosity of the fluid, and diameter of the needle opening. With digital Positive-displacement-type
a particular volume and rate of delivery can be specified. Wondering which type to choose? If the
volumes you need to deliver are less than 10 nanoliters, then pressure-type is really the only
choice because positive-displacement units don't have the precision for picoliter injections
due to thermal expansion and other variables that are larger than picoliters. From tens of nanoliters
up to hundreds of microliters, you can take advantage of the convenience of positive-displacement
injectors that require no external pressure source and let you deliver exact volumes.
In most pressure-type 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 aid in reducing
needle clogging. However, no matter how careful one is, needles
occasionally do clog. For these cases, a short blast of a "clearing
pressure," higher than the normal injection pressure, can be useful to
unclog the needle.
HOW TO CHOOSE A MICROINJECTOR
To choose a microinjector, take into account some of the following
- The volume you'll be injecting
- Viscosity of the medium that is being injected
- Cost of the medium that is being injected
- Needle tip diameter and size of particulates in medium you're injecting (with regard to clogging)
- Total volume you'll be injecting (consider the economy injecting multiple targets
with the same needle vs. issues of cross-contamination of samples)
- The pressure source (i.e. will you use a lab air jet, compressed
tank, or positive displacement?)
- Do you need a dual microinjector/micromanipulator system to both hold
the target as well as to inject it?
- Will you use the microinjector for only one simple application, or do
you have other future experimental set-ups in mind for the future?
- Will it be easier for you to backfill or frontfill your needle?
WILL ONE OF THE FOUR MICROINJECTORS ABOVE WORK FOR ME?
We are confident that one of the four systems showcased above — MINJ-1
— will meet popular microinjection needs. We have taken the guesswork out of decision making, and put together a variety of low-cost, high-quality solutions for researchers. Call us if you need something different or customized!
NEED MORE HELP ON DECIDING YOUR MICROINJECTOR?
We carry a range of microinjectors that have a variety of features to
fit almost any research need and that will also fit a variety of
budgets. Since we design and manufacture most of the microinjectors
we sell, we are also happy to help provide you with additional features
and modifications you may need for cutting edge research. Please feel
free to contact us directly if you need additional help in choosing
the right microinjector for your current and/or future applications or
if you need a customized microinjector for a specialized use.
Microinjection does not have to be a complicated and difficult task,
and Tritech Research is here to help you choose the best microinjector
for your research and your budget. We also stock a variety of
microscopes, micromanipulators, needle holders, borosilicate glass,
needle pullers, microforges, microgrinders, and all of the other
accessories required to perform your work.
If you have any questions about our products or your particular
application, we're here to help.