the last 8 years the Wessex Regional Genetics Laboratory (WRGL)
has developed an interest in automated systems to reduce the workload
in diagnostic cytogenetics. These developments are now continuing
in conjunction with NGRL (Wessex).
1997 WRGL successfully introduced a liquid handling cartesian robot
to harvest coverslip (surface) cultures from amniotic fluid samples.
This procedure followed principles well established in US laboratories
and has played a major part in achieving a prenatal reporting time
of 7 days, a figure that has been maintained for the last 6 years. Encouraged
by this success, we turned to an automated system for harvesting
suspension (blood) cultures, following a routine devised by the
Bristol Laboratory. This routine uses a liquid handling cartesian
robot to aspirate and dispense reagents into tubes of cultured
blood samples and finishes with a fixed cell suspension ready for
making into chromosome preparations. The routine produces
reproducibly good quality cell suspensions but a major drawback
is the fact that the programme has to be halted at stages throughout
the procedure to allow centrifugation of the cell suspension. Consequently
we have not integrated this procedure into routine use because
of the waiting periods involved.
next stage of chromosome preparation to receive our attention was
the preparation of slides from fixed cell suspension. This
procedure uses a liquid handling cartesian robot to dispense a
small (10microlitre) drop of fixed cell suspension onto an inclined
slide. The success of the procedure relies on the evaporation
of the alcoholic fixative in a temperature and humidity controlled
environment. Automating this stage has allowed us to develop
a system of eye-readable bar-coding which avoids any possibility
of sample switching during the generation of slides.
lends itself to higher throughput of samples but perhaps more importantly
it leads to standardisation of chromosome quality by removing the
variability inherent between different operators. By automating
the stages of harvesting and slide-making it is hoped that chromosome
banding will also lend itself to automation.
Multiprep is a novel robot that has been co-developed with Genial
Genetic Solutions Limited for the rapid harvesting of substrate cultures.
We are continuing to evaluate the reliability of this machine for
harvesting cultures of amniotic fluids, chorionic villi and fibroblasts
grown on glass cover slips in 35mm Petri dishes.
Multiprep has a small footprint (700x500mm), has been designed to
process 5 cover slips at the same time, incorporates a vapour filter
to remove harmful acetic acid vapours and will process 40 cover slips
in less than an hour. The chromosome preparations are of high quality
and band in a similar fashion to those produced on our Cartesian
Multiprep is entirely self-contained and ours is mounted on a dedicated
trolley which means that, because of its unique vapour scrubbing
device, it can be used anywhere in the department as space dictates.
video clip of Multiprep in action.
We are currently developing a procedure
to allow substrate cultures to be dried ‘in-situ’ which
will obviate the need for a dedicated temperature and humidity
Future projects include a novel approach to automated harvesting
of suspension cultures, further development of slide making from
suspension cultures, and automated G-banding of both suspension and