title: DNA purification from crude samples for human identification using gradient elution isotachophoresis.
abstract: Gradient elution isotachophoresis (GEITP) was demonstrated for DNA purification, concentration, and quantification from crude samples, represented here by soiled buccal swabs, with minimal sample preparation prior to human identification using STR analysis. During GEITP, an electric field applied across leading and trailing electrolyte solutions resulted in isotachophoretic focusing of DNA at the interface between these solutions, while a pressure-driven counterflow controlled the movement of the interface from the sample reservoir into a microfluidic capillary. This counterflow also prevented particulates from fouling or clogging the capillary and reduced or eliminated contamination of the delivered DNA by PCR inhibitors. On-line DNA quantification using laser-induced fluorescence compared favorably with quantitative PCR measurements and potentially eliminates the need for quantitative PCR prior to STR analysis. GEITP promises to address the need for a rapid and robust method to deliver DNA from crude samples to aid the forensic community in human identification.
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. elizabeth.strychalski@nist.gov
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Strychalski
authors.forename: Christopher
authors.initials: C
authors.lastname: Konek
authors.forename: Erica L R
authors.initials: EL
authors.lastname: Butts
authors.forename: Peter M
authors.initials: PM
authors.lastname: Vallone
authors.forename: Alyssa C
authors.initials: AC
authors.lastname: Henry
authors.forename: David
authors.initials: D
authors.lastname: Ross
mesh_terms: D004247:DNA / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D057625:Isotachophoresis / Q000379:methods*; D008297:Male; D018895:Microsatellite Repeats; D009061:Mouth Mucosa / Q000737:chemistry / Q000166:cytology; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D013048:Specimen Handling
chemical_list: D004247:DNA
keywords: DNA; Forensic DNA typing; Gradient elution isotachophoresis; Human identification; Soil