omation mbers - Society for Laboratory Automation and Screening

1:30 pm Thursday, February 5 Microfluidics – Small Volume Dispensing Room A4
Johan Nilsson
Lund University
Ole Romersvag 3
Lund, SE-221 00 Sweden
johan.nilsson@elmat.lth.se
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Co-Author(s)
Lars Wallman, Simon Ekström, Thomas Laurell
Lund University
György Marko-Varga
Astrazeneca, Lund
Proteomic Sample Preparation Using Piezo Dispensing and Capillary Force Driven Flow
Despite the high sensitivity and relatively high tolerance for contaminants of matrix assisted laser desorption/
ionization time of flight mass spectrometry (MALDI-TOF MS) there is often a need to purify and concentrate the
sample solution, especially after in-gel digestion of proteins separated by two dimensional gel electrophoresis. A
capillary force filling microsystem with a silicon microextraction chip or array and a piezoelectric microdispenser
for sample clean-up and trace enrichment of peptides was manufactured and investigated. The micro extraction
array was used to trap reversed phase chromatography media (Poros R2 beads) that facilitates the sample
purification/enrichment of contaminated and dilute samples. The outlet of the extraction array was docked to the
inlet of the capillary force filling microdispenser. 2 microliter of a matrix/elution solution that releases the peptides
from the beads was applied at the inlet of the extraction array and fills both the extraction array and the dispenser
by capillary force. The sample plug in the dispenser was deposited into a small spot on (< 400 micrometer) on the
MALDI target increasing the sensitivity of the analysis. Using capillary forces only to fill the extraction array and the
dispenser simplifies the operation of the system since there is no need for a tight connection between the matrix/
elution solution supply and the inlet. The potential problem of trapping air bubbles in the dispenser during filling is
also minimized.
2:00 pm Thursday, February 5 Microfluidics – Small Volume Dispensing Room A4
Donald Schwartz
DRD
83 Pine Street
West Peabody, Massachusetts 01960
donschwartz@drddiluter.com
Co-Author(s)
Donald S. Martin
Differential Nano-Pipettor (NanoBlast): A Non-contact Pipettor That Handles Nanoliters for
Plate Replication, Sample Transfers, Spotting, and Arrays
Solid pistons, motor-driven smoothly and swiftly through seals, have been the mainstay of automated pipetting
systems. However, the escalating demands to pipette low microliter or nanoliter volumes, contact free, are too
severe for this classic design to meet because its single resolution mechanism cannot give both the fine aspiration
resolution and high flow for sample blowoff that is needed. Hanging drops are common. An ever-morphing
mélange of sensual robots cavorting with whackers, thwackers, pokers and zappers seeks to overcome this
fundamental failing. The NanoBlast (unique and patent-pending) is a new miniaturized configuration of DRD’s
Differential Displacement technology. Two pistons whose diameters differ by a few thousandths of an inch move
together with respect to the same chamber (DRD Differential Mode). The very small cross sectional area difference
gives extremely fine resolution, a robust 1.8 mm excursion/µL to call on to aspirate smoothly down to 50 – 100 nL
even with disposable tips. Then only one piston moves (DRD Bulk Mode) and the abundant flow power (455 µL/
inch) blows the minute sample out through a comfortable-sized orifice without damaging it (BlastoffTM) – to its
microplate, array, spotting or MALDI target. No valves or auxiliaries are needed and there are no small seals. With
conventional disposable plastic tips with IDs 0.016" – 0.020", the NanoBlast handled samples from 2 uL down
to 170 nL (typical SD 30 – 35 nL). A fixed steel probe with tip ID 0.019" gives a SD of 20 nL. Disposable and fixed
steel probes with tip IDs of 0.012" transfer proportionate-appearing drops down to 25 nL; quantitative studies of
this are underway. The NanoBlast debuts as a bank of 8 and as a microplate-spaced block of 96, embodying
the simplicity and smooth control of the classic pipettor with enormous additional range and reliability from its new
DRD Differential Displacement power.