title: Dispersion serial dilution methods using the gradient diluter device.
abstract: A solute aspirated into a prefilled tube of diluent undergoes a dilution effect known as dispersion. Traditionally the effects of dispersion have been considered a negative consequence of using liquid-filled fixed-tip liquid handlers. We present a novel device and technique that utilizes the effects of dispersion to the benefit of making dilutions. The device known as the Gradient Diluter extends the dilution range of practical serial dilutions to six orders of magnitude in final volumes as low as 10 μL. Presented are the device, dispersion methods, and validation tests using fluorescence detection of sulforhodamine and the high-performance liquid chromatography/ultraviolet detection of furosemide. In addition, a T-cell inhibition assay of a relevant downstream protein is used to demonstrate IC(50) curves made with the Gradient Diluter compare favorably with those generated by hand.
authors.affiliation: Amgen, Inc., Thousand Oaks, California 91320, USA. l.walling@stratec.com
authors.forename: Leslie
authors.initials: L
authors.lastname: Walling
authors.forename: Craig
authors.initials: C
authors.lastname: Schulz
authors.forename: Michael
authors.initials: M
authors.lastname: Johnson
mesh_terms: D001681:Biological Assay; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000032:analysis; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004232:Diuretics / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005665:Furosemide / Q000494:pharmacology; D006801:Humans; D007201:Indicator Dilution Techniques / Q000295:instrumentation*; D007202:Indicators and Reagents; D012015:Reference Standards; D012235:Rhodamines / Q000032:analysis; D012984:Software; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013601:T-Lymphocytes / Q000187:drug effects
chemical_list: D004396:Coloring Agents; D004232:Diuretics; D007202:Indicators and Reagents; D012235:Rhodamines; C022027:lissamine rhodamine B; D005665:Furosemide; D004121:Dimethyl Sulfoxide