title: Microchip separations of protein biotoxins using an integrated hand-held device.
abstract: We report the development of a hand-held instrument capable of performing two simultaneous microchip separations (gel and zone electrophoresis), and demonstrate this instrument for the detection of protein biotoxins. Two orthogonal analysis methods are chosen over a single method in order to improve the probability of positive identification of the biotoxin in an unknown mixture. Separations are performed on a single fused-silica wafer containing two separation channels. The chip is housed in a microfluidic manifold that utilizes o-ring sealed fittings to enable facile and reproducible fluidic connection to the chip. Sample is introduced by syringe injection into a septum-sealed port on the device exterior that connects to a sample loop etched onto the chip. Detection of low nanomolar concentrations of fluorescamine-labeled proteins is achieved using a miniaturized laser-induced fluorescence detection module employing two diode lasers, one per separation channel. Independently controlled miniature high-voltage power supplies enable fully programmable electrokinetic sample injection and analysis. As a demonstration of the portability of this instrument, we evaluated its performance in a laboratory field test at the Defence Science and Technology Laboratory with a series of biotoxin variants. The two separation methods cleanly distinguish between members of a biotoxin test set. Analysis of naturally occurring variants of ricin and two closely related staphylococcal enterotoxins indicates the two methods can be used to readily identify ricin in its different forms and can discriminate between two enterotoxin isoforms.
authors.affiliation: Sandia National Laboratories, P.O. Box 969, MS 9201, Livermore, CA 94551, USA. jfruet@sandia.gov
authors.forename: Julia A
authors.initials: JA
authors.lastname: Fruetel
authors.forename: Ronald F
authors.initials: RF
authors.lastname: Renzi
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Vandernoot
authors.forename: James
authors.initials: J
authors.lastname: Stamps
authors.forename: Brent A
authors.initials: BA
authors.lastname: Horn
authors.forename: Jay A A
authors.initials: JA
authors.lastname: West
authors.forename: Scott
authors.initials: S
authors.lastname: Ferko
authors.forename: Robert
authors.initials: R
authors.lastname: Crocker
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Bailey
authors.forename: Don
authors.initials: D
authors.lastname: Arnold
authors.forename: Boyd
authors.initials: B
authors.lastname: Wiedenman
authors.forename: Wen-Yee
authors.initials: WY
authors.lastname: Choi
authors.forename: Daniel
authors.initials: D
authors.lastname: Yee
authors.forename: Isaac
authors.initials: I
authors.lastname: Shokair
authors.forename: Ernest
authors.initials: E
authors.lastname: Hasselbrink
authors.forename: Philip
authors.initials: P
authors.lastname: Paul
authors.forename: David
authors.initials: D
authors.lastname: Rakestraw
authors.forename: Debbie
authors.initials: D
authors.lastname: Padgen
mesh_terms: D046209:Electrophoresis, Microchip / Q000295:instrumentation / Q000379:methods*; D004768:Enterotoxins / Q000302:isolation & purification; D017743:Equipment Reuse; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D008904:Miniaturization; D012276:Ricin / Q000302:isolation & purification; D012278:Ricinus / Q000737:chemistry; D012680:Sensitivity and Specificity; D013211:Staphylococcus aureus; D014118:Toxins, Biological / Q000302:isolation & purification*
chemical_list: D004768:Enterotoxins; D014118:Toxins, Biological; C026066:enterotoxin A, Staphylococcal; C031818:enterotoxin B, staphylococcal; D012276:Ricin