LabAutomation 2006 - SLAS

MP25
Patrick Cooley
Microfab Technologies, Inc.
Plano, Texas
patrick.cooley@microfab.com
Where Laboratory Technologies Emerge and Merge
PiezoLC Microdispenser for MALDI-TOF Analysis
Co-Author(s)
Ting Chen
David Wallace
Microfab Technologies, Inc.
Femia Hopwood
Andrew Gooley
Proteome Systems, Ltd.
Frantisek Svec. University of California, Berkeley
The PiezoLC is an ink-jet system to deliver micro-volumes (0.1 to 100nL) of proteolysed peptides onto MALDI-TOF MS targets for
subsequent mass spec analysis. A porous polymer monolith is located within the glass capillary of the ink-jet dispensing device to provide
chromatographic separation of peptides. The peptide sample is loaded onto the integrated chromatography column (reversed phase) and an
elution buffer separates the peptides, as the buffer passes through the column. The eluted peptides exit the orifice of the piezoelectric device
in the form of drops and land onto a MALDI-TOF MS target plate preserving the chromatographic separation. The analysis of the peptides
can then be performed at a later date and multiple times. The PiezoLC can be a useful tool for the identification and characterization
of proteins from finite samples. Low-abundance proteins may not be detected during MS analysis, as they are commingled with highabundance
proteins within protein digests and are obscured by ion suppression effects. The chromatographic separation of peptides
by the PiezoLC can reduce ion suppression and improve resolution of MALDI-TOF MS analysis for applications, such as peptide mass
fingerprinting. The PiezoLC separation of tryptic digests of Bovine Serum Albumin (BSA) resulted in a larger number of peptides identified in
comparison to the control. This resulted in a higher degree of amino acid sequence coverage and improved protein identification.
MP26
Mary Cornett
Innovadyne Technologies, Inc.
Santa Rosa, California
mcornett@innovadyne.com
Co-Author
Anca Rothe
Innovadyne Technologies, Inc.
Meeting the Liquid Handling Challenges of Low Volume Cell Assays
One of the main challenges faced in the development of automated cell-based screening systems is the requirement to accurately and
gently dispense low volumes of assay cells. Traditional and flow-through liquid handlers, commonly used in HTS applications, can dispense
in a manner that results in shearing stress to live cells impacting viability. Additionally, typical instrument designs with mechanical valves
included in the flow path, often contribute to imprecision through contamination and the clogging of flow paths. While the precision of
solenoid-based dispensing systems has long been recognized, their widespread acceptance has been tempered with concern regarding
performance or maintenance issues. Here, we discuss a solenoid-based system that overcomes these issues by exposing the solenoid
valves only to deionized water at a constant pressure, allowing them to operate efficiently and effectively. In addition to improving
robustness, the system design ensures that the aspirated sample never contacts moving parts and only encounters a very simple flow
path, which is vital for the successful dispensing of live cells. We also present data from several homogenous cell assay types that
demonstrate consistent maintenance of cell viability in a 1536-well format, as well as excellent dispensing precision of cells and several cell
assay reagents in the low microliter dispense range.
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