The dragonfly discovery instrument has an array of up to 10 dispensing heads located inside the
top cover. The dispensing mechanism automatically interlocks with the syringe assembly once it is loaded into the instrument. In each of the heads there is a tight fitting piston that travels
within a pipette barrel, which when coupled to the instrument's piston rod forms the positive
displacement syringe. The distance and rates of acceleration and deceleration of the piston control how and when liquid is ejected from the tip.
Syringes can be synchronized for high throughput dispensing or utilized independently for
reagent flexibility. The syringes aspirate reagents from a variety of reservoir types.
Each dragonfly discovery head is capable of aspirating between 0.3mL and 4mL. It can dispense
volumes of 200nL - 4mL, with up to 4 mL in a single syringe fill. These volumes can be achieved
with CVs below 5% from 1μL and 10% from 0.2 to 1μL, for a wide range of fluid types.
Deep well block dragonfly discovery
Deep well block (DWB) dragonfly discovery extends the upper end of the range of supported plate heights, to support the use of deep well blocks.
DWB instruments are supplied with an insert for use with standard depth plates.
The application software instructs users to fit (shown below) or remove the insert based on the
height of the selected plate.
Dispensing
dragonfly discovery uses disposable syringes to aspirate and dispense samples. Each syringe is a positive displacement pipette that uses its own HDPE plunger as opposed to an air gap or system liquid. The syringe bodies are moulded from polypropylene.
Note: Syringe and plungers are designed to be single use.
The syringe plate securely locates the syringes and has access slots to help guide the syringes to their correct position.
The syringe clamp positions the tips of the dispensing syringes in relation to the well plate. The
clamp automatically closes prior to a dispense run and ensures that the tips are accurately
positioned. In normal operation the clamp will not open until the run has completed.
The syringe clamp also helps prevent removal of a syringe from the instrument while the
dispensing head plunger rod is down. Removing a syringe body with the plunger rod down may
damage the dispensing rod.
The syringe guard protects the syringes from damage during operation.
Reagent loading and aspirating
Syringes are filled from reservoirs, which are manually loaded with reagents. There is one
reservoir per head position and a choice of two capacities; either 10mL standard reservoirs or 1.5
mL Low Dead Volume (LDV) reservoirs. You can use a mixture of reservoir types, as shown below.
On the 10mL reservoir there are two level marks moulded into the inside walls of the reservoir to
indicate fill levels of 5mL and 10mL (maximum) respectively. The LDV reservoir has a maximum fill level of 1.4mL. The reservoirs are v-bottomed to minimise dead volume.
The reservoirs are moulded from PP and can be washed for reuse or disposed of after use.
The reservoirs are loaded in a plastic tray that securely positions each reservoir in its correct
position for aspiration.
Auto Feed Reservoirs (AFRs)
Auto Feed Reservoirs (AFRs) are an optional extra for dragonfly discovery which allow supply of
higher volumes of reagents than with the standard reservoirs.
The reservoir tray is raised to position the reservoirs at the correct height for the syringes to
aspirate liquids. After aspiration, the reservoir plate is lowered from the syringe tips, initially at a
very slow speed to ensure effective removal of the fluids from the outside surfaces of the syringe
tips. Once clear of the tips, the reservoir tray moves to its parked position at a higher speed.
During dispensing operations, the reservoir tray will be in its lowered home position.
Reagent cooling
To keep reagent reservoirs cool, you use a LDV reservoir and a reservoir cooling block. This is a
passive cooling system, so you will not be able to control reagent temperature precisely.
- Put the reservoir cooling block in a freezer for 2 hours.
- Place the chilled block in the reservoir tray beneath the LDV reservoir.
Plate handling
Plates are held securely in a plate nest, which has a latch to ensure correct registration of the well plate in the nest and to retain it it securely. In the home position, the latch is released to enable loading and unloading.
The plate stage securely holds and moves the well plate in relation to the dispensing heads. It
positions the well plate correctly in the horizontal and vertical planes. The plate stage will park
with the plate nest in an accessible position before and after each run for plate loading and
removal.
Plate incubation lid
The incubation lid allows plates used in a run with a dispensing time course to be parked under a
lid between dispenses, to minimise evaporation. The incubation lid is held in place with magnets
and can be removed from the holder to access the plate.
