title: Evaluation of a digital dispenser for direct curve dilutions in a vaccine potency assay.
abstract: Dilutions are a common source of analytical error, both in terms of accuracy and precision, and a common source of analyst mistakes. When serial dilutions are used, errors compound, even when employing laboratory automation. Direct point dilutions instead of serial dilutions can reduce error but is often impractical as they require either large diluent volumes or very small sample volumes when performed with traditional liquid handling equipment. We evaluated preparation of dilution curves using a picoliter digital dispenser, the HP, Inc. / TECAN D300 which is capable of accurately delivering picoliter volumes directly into sample wells filled with assay diluent. Dilution linearity and variability of the direct dilutions were similar to or less than those generated with a traditional liquid handler as measured using a fluorophore assay and an ELISA used to measure vaccine potency. Minimum concentrations for detergent in the dispensed sample were identified but no correlation with detergent characteristics was observed. The tolerance to protein in the sample was evaluated as well with up to 5% BSA having no impact on dispense linearity and precision. We found the digital dispenser to reduce automation complexity while maintaining or improving assay performance in addition to facilitating complex plate lay-outs.
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: christopher.roselle@merck.com.
authors.forename: Christopher
authors.initials: C
authors.lastname: Roselle
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: dana.whitehouse@merck.com.
authors.forename: Dana
authors.initials: D
authors.lastname: Whitehouse
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: thy_follmer@merck.com.
authors.forename: Thy
authors.initials: T
authors.lastname: Follmer
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: frances_ansbro@merck.com.
authors.forename: Fran
authors.initials: F
authors.lastname: Ansbro
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: Silikhone_bouaraphan@merck.com.
authors.forename: Silikhone
authors.initials: S
authors.lastname: Bouaraphan
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: liming_guan@merck.com.
authors.forename: Liming
authors.initials: L
authors.lastname: Guan
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: shake_wang@merck.com.
authors.forename: Sha-Ke
authors.initials: SK
authors.lastname: Wang
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: mary_retzlaff@merck.com.
authors.forename: Mary
authors.initials: M
authors.lastname: Shank-Retzlaff
authors.affiliation: Merck & Co. Inc., Kenilworth, NJ. Electronic address: thorsten_verch@merck.com.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Verch
mesh_terms: D057205:Automation, Laboratory; D002138:Calibration; D003902:Detergents / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation* / Q000592:standards; D004867:Equipment Design; D005456:Fluorescent Dyes / Q000737:chemistry; D057166:High-Throughput Screening Assays / Q000295:instrumentation* / Q000592:standards; D008904:Miniaturization; D012015:Reference Standards; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence; D064166:Vaccine Potency
chemical_list: D003902:Detergents; D005456:Fluorescent Dyes
keywords: D300; Direct dilution; Low volume dispense