omation mbers - Society for Laboratory Automation and Screening

TP017
Madhu Prakash Chatrathi
New Mexico State University
Chemistry & Biochemistry
MSC 3C; North Horseshoe Drive
Las Cruces, New Mexico 88001
madhupra@hotmail.com
Co-Author(s)
Joseph Wang, Alexander Muck, Scott Spillman, Gautham
Sridharan and Michael Jacobs, New Mexico State University
Michael Schonning, Institute of Thin Films and Interfaces,
Jülich, Germany
Rapid Fabrication of Poly(methylmethacrylate) Microfluidic Chips by Atmospheric Molding
Microfluidic devices are finding numerous applications in analytical chemistry. Most early reports on miniaturized
analytical systems have relied on glass or silicon substrates. However, the cost of producing glass microchips
and the ease of fabrication has driven researchers and producers to seek for alternative materials. Recent efforts
have thus led to increasing use of polymeric materials [poly(dimethylsiloxane) (PDMS), poly(methylmethacrylate)
(PMMA) or polycarbonate (PC)] in the preparation of chip-based devices. PMMA has been particularly useful for
analytical microsystems, owing to several advantages, including high chemical and mechanical stability and good
support of the electroosmotic flow. A greatly simplified method for fabricating PMMA separation microchips is
introduced. The new method of fabrication relies on UV initiated polymerization of the monomer solution in an
open mold under ambient pressure. Silicon microstructures are transferred onto the polymer substrate by molding
a methylmethacrylate solution in a sandwich (silicon-master/Teflon-spacer/glass-plate) mold. The chips are
subsequently assembled by thermal sealing of the channel and cover plates. The new approach brings significant
simplification of the process of fabricating PMMA devices and should lead to a widespread low-cost production
of high-quality separation microchips and obviates the need for specialized replication equipment and reduces
the complexity of prototyping and manufacturing. While the new approach is demonstrated on PMMA microchips,
it could be applied to other materials that undergo light-initiated polymerization. Ongoing experiments in our
laboratory are focused on tailoring the electroosmotic flow characteristics by changing the chemical properties of
the bulk microchip material via judicious choice of the monomer material.
TP018
Melissa Cheu
Genentech, Inc.
BioAnalytical Assays
1 DNA Way, Mailstop 86B
South San Francisco, California 94080
melissa@gene.com
Validation of the Packard Multiprobe HT for Dilution of Biological Matrix Samples
154
Co-Author(s)
Brent T. Nakagiri
Riddhi Patel
Patricia Y. Siguenza
The BioAnalytical Assays Department at Genentech, Inc. performs drug level measurement and antibody to
product testing in support of pre-clinical and clinical studies. To support drug level measurements, biological matrix
samples are diluted in various diluents to fall within the standard curve ranges of 96-well plate based ELISAs.
Since the concentration of drug varies in the samples being tested, some samples may need to be diluted more
than others to fall within the standard curve range. The need for a dilution instrument that could simultaneously
dilute a set of samples to multiple endpoints led to the selection of the Packard Multiprobe HT dilutor, a robotic
liquid handling system capable of delivering up to eight different liquid volumes simultaneously through eight
independently controlled syringes. Since BioAnalytical Assays runs samples in a regulated environment, validation
of the Packard Multiprobe HT was performed before the instrument was put into use for dilution of samples.
Validation testing included accuracy and precision checks of the instrument, error generation testing, and recovery
of reference material diluted into plasma, serum, and buffer.