M96 use twelve 8-way dispensing heads and twelve 8-way
aspirating heads to wash all the wells of a microplate simultaneously.
The dispense heads are positioned to direct a stream of wash fluid at
the center of each well and the aspirate heads are held above the
microplate, clear of the fluid, until aspirating begins, thereby
avoiding cross-contamination between plates.
fluid volumes, dispense/aspirate modes, number of wash cycles, soak
times and mixing times are all programmable. Nine programs can be
stored in memory. Each program can include up to four subroutines.
This ability to LINK subroutines allows different
types of wash cycles to be used within one program.
of menus, presented on the alphanumeric display, guides the user
through setting up procedures. Programs can be created from scratch,
edited and "cloned" from one stored program to others. The program
most recently used in a session automatically becomes the default when
the machine is switched on for a new session. User communication with
the washer is via a numeric keypad. Keys 1 through 4 are context
sensitive (sometimes known as "soft" keys), and are used to select
supply of distilled water is kept attached to the washer, rinsing and
emptying the washer at the end of a session requires only a single
the washer there must be a wash solution supply line connected to the
"Fluid 1" connector, and an extraction system connected to the
"Vacuum" connector. The internal logic will not allow a wash program
to be executed unless the washer has been primed at least once since
PRIME key and wait about 70 seconds. If you want to check that the
washer is really priming, watch the syringe through the window and
assure yourself that, by the end of the priming process, it is full of
liquid (a small residue bubble is normal). If you are not satisfied
that the system is fully primed, you may repeat the PRIME as many
times as necessary.
PRIME too early. If you are using a typical saline wash solution you
should avoid priming more than about 20 minutes before you are ready
to start washing plates.
automatic system initialization occurs every time the washer is
powered up. Initialization causes all moving parts of the washer to
actuate as a function check. If all is well, the Main Menu is displayed
after about 20 seconds, and the washer is ready for use.
Microplates are available with various well shapes and sizes. The M96 position dispense and aspirate tubes as precisely as possible
and therefore have to be "trained" to know some physical dimensions
pertaining to the microplate being used. The profile procedure is a
preliminary step in editing a program (and each program has its own
unique profile stored along with the other parameters). What profiling
does is define where on the "Z" (vertical) axis the top surface of the
plate is, where the bottom of the wells are, and where on the "X" axis
the centers of the wells are.
particularly important to carry out the profiling procedure if you are
going to use round bottom, V-bottom or unusually shallow wells to make
it unlikely that you will crash the aspirate tubes into the plate if
you omit to run profile. If you do not run profile you will probably
find your washer leaves too much fluid in the plate typical
used for profiling must be representative of the plates you will wash
with the program concerned. However, do not use a plate that is coated
or treated or one you subsequently need to wash. The act of profiling
causes the aspirate tubes to touch the plate and material from the
plate could contaminate the tubes.
of both the dispense tubes and aspirate tubes are rather narrow. This
is a necessary feature because achieving even dispensing or aspiration
through 96 separate channels requires that no one channel be too
"easy" a route for liquid to flow through. A shower head or lawn
sprinkler works on the same principle.
showers and sprinklers, any buildup of salt deposits in the narrow
bores will cause uneven flow and will quickly lead to the complete
blockage of one or more tubes. As most plate washing fluids are
salt-laden buffers, the M96 has an entirely separate fluid inlet port
for distilled water and a one-step rinse procedure to thoroughly
displace all salt solutions from the internal plumbing.
strongly recommend that the rinse procedure be carried out whenever
the washer is being shut down. The consequential use of wash fluid for
typically worthwhile because stripping the tubes down for cleaning,
although easy to do, does take time and, of course, requires
7 WASH TYPES
application requires the simple removal of a reagent presently in the
plate wells, the straightforward dispense/aspirate wash type (type
1) is probably adequate. This is the wash type that is
quickest and uses the least amount of wash fluid.
are concerned about ensuring that material high up on the walls of the
wells is washed away, SUPERWASH (type 2) should be
used because it fills the wells to the brim with simultaneous
aspiration from the top surface to ensure no well-to-well
need to leave the plate as dry as possible, use SUPERVAC (type
3). This causes the aspirate tubes to traverse the well
bottoms extracting more residue liquid. If you only need the extra
aspirating efficiency of SUPERVAC for the last cycle, use the linking
feature to append a SUPERVAC subroutine to a normal aspiration.
and SUPERVAC can be used together (type 4), and any permutation of wash types can be run sequentially if the
linking feature is used in defining a program.
only (type 5), aspirate only (type 6),
and SUPERVAC only (type 7) are also available. These
wash types may be useful for unusual applications, but their main
utility is as subroutines linked to the more conventional wash types.
types involving aspiration start with an aspiration when they
are used as the first subroutine. The dispense only type does not
aspirate. You should be careful to not flood a plate when using the
dispense only type (remember to set the "number of washes" to be 1
when doing dispense only).
subroutines is a very useful feature, once the concept is understood.
Here are some examples to illustrate the applicability:
you need to leave the plate as empty as possible but also want to
process plates as quickly as possible through three wash cycles. A 3
cycle dispense/SUPERVAC would fulfill the first requirement but a 2
cycle dispense/aspirate followed by a single dispense/SUPERVAC would
imagine that you are concerned about contaminants high up on the wall
of the wells but want to minimize consumption of wash fluid, and again
need to wash three times. A three cycle SUPERWASH washes the walls but
a single SUPERWASH linked to 2 ordinary dispense/aspirates may serve
as well, uses less fluid and is also a little quicker.
what if you want to leave the plates full of wash fluid after, say 2
complete wash cycles? Two dispense/aspirate cycles followed by a
dispense only cycle.