Breakthrough in forensic workflow automation, eliminating the
Transcription
Breakthrough in forensic workflow automation, eliminating the
Breakthrough in forensic workflow automation, eliminating the sample preparation and lysis bottlenecks with the AutoLys STAR: Technology and Validation Study Laurent Baron 1, Bas de Jong 2, Lois Tack 3, Maureen Antonie 2, Flurin Gallman 1, and Rainer Beckbissinger 1 1 Hamilton Robotics, P.O. Box 26, CH-7402 Bonaduz GR, Switzerland, lbaron@hamiltonrobotics.com 2 The Netherlands Forensic Institute (NFI), Postbus 24044, 2490 AA The Hague, Netherlands, b.de.jong@nfi.minvenj.nl 3 Hamilton Robotics, 4970 Energy Way, Reno NV 89502, lois.tack@hamiltoncompany.com EAFS 2012 Introduction AutoLys Tube™ Features Forensic DNA sample processing frequently involves manual lysis and extraction to prepare cleared lysates from various biological samples (swabs, cloth cuttings, etc.) prior to DNA purification. Lysis steps are time-consuming, introduce gaps in sample workflows, loss of traceability and can increase contamination risks and user errors. Sample preparation and lysis steps are major bottlenecks in many forensic labs. We describe the Microlab® AutoLys STAR®, a new automated lysis solution from Hamilton Robotics, and show validation data from the Netherlands Forensic Institute (NFI). Figure 3: AutoLys Tube side view Figure 4: Tube inner diameter Wide inner tube diameter allows efficient mixing during lysis shaking step. Cap Inner tube with PTFE filter Outer tube with 2D barcode Inner diameter: Automated Process Figure 1: AutoLys system workflow Process evidence sample Match barcode Transfer sample to AutoLys tube Place AutoLys tubes in racks Load racks and reagents on STAR Samples ready to purify DNA AutoLys steps AutoLys Tubes (Fig. 3) have been designed specifically for the automated lysis of forensic samples. The wide opening of the inner tube (Fig. 4) allows user to easily insert various materials such as swabs, cigarette butts, fabrics and tape. AutoLys Tube = 11 mm Standard 1.5-2 mL microfuge tube = 8-9 mm Figure 5: AutoLys Tube with swab head Cotton swab head Integrated filter allows automated separation of lysate from trace carrier. The complete lysis workflow takes place in a single vial, thus maximizing yields, eliminating contamination risks and drastically reducing operator time. Lysis buffer (500 uL) Swab sample is completely immersed by liquid; add up to 500 uL of lysis buffer. Figure 2: System deck layout and components – 96 sample processing Tips Tips Tips Tips Tips Tips Tips Tubes Tips Sample Figure 6: AutoLys Tube workflow Cap Rack AutoLys Rack Cap Rack Output Rack Output Rack AutoLys Rack Heater Shaker Balance Racks Balance MAGNET Racks AutoLys Rack AutoLys Rack AutoLys Rack Heater Shaker Add Lysis Buffer Centrifuge Heater Shaker Liquid Waste Heater Shaker Heater Shaker Lift and Lock Incubate and Shake 2D BC Reader Spin Clear Lysate Reagent Reagent Reservoirs Reservoirs HHS Heater Shaker blocks automate incubation & shaking on the robot deck Integrated 2D barcode reader for total sample tracking throughout the process Integrated on-deck centrifuge separates sample material from cleared lysate Figure 7: AutoLys Channel Functions Transport Capping and individual tubes to HHS for incubation decapping of individual tubes Perform “lift and lock” step, transforming AutoLys Tube into spin column Results AutoLys tube performance using the AutoLys STAR system was directly compared to manual processing results using QIAshredder filter spin columns. Comparative yields were calculated and gave a “scoring coefficient”. Subsequent DNA purification from all lysates was carried out manually following the NFIvalidated protocol. DNA samples were then quantified and analyzed by STR typing. Sample Preparation Blood (high): 5 uL undiluted blood spotted on cotton swab Saliva (high): 40 uL undiluted saliva spotted on cotton swab Blood (low): 5 uL (15x diluted) blood spotted on cotton swab Saliva (low): 11 uL (3x diluted) saliva spotted on cotton swab Lysis and DNA Extraction Lysis on AutoLys STAR or manual: 450 uL lysis buffer and 50 uL ProK, incubation 4hr @56deg C. Manual DNA extraction of all lysates using QIAamp® DNA Mini Kit (QIAGEN®): Binding, washing, and elution in 2x 50 uL elution buffer Downstream Processing DNA quantification - Quantifiler® Duo DNA Quantification Kit (Life Tech.®) STR amplification - AmpFlSTR® NGM Next Generation Multiplex Kit (Life Tech.®) Fragment analysis - 5sec@3kV on ABI 3130xl™ Genetic Analyzer (Life Tech.®) Scoring Coefficient 1 Autolys / QIashredder Sample Type DNA Quantification STR Peak Heights2 Blood (high) 118.1 % 124.2 % Saliva (high) 120.8 % 116.2 % Blood (low) 93.6 % 88.0 % Saliva (low) 97.3 % 91.5 % 1 Scoring coefficient based on overall data from initial tests. 2 Average of peak heights from DNA profiles, corrected for dilution factor (i/a) and amount of input in PCR. Developmental validation study performed by NFI Part 1 – Initial testing of AutoLys Tubes and STAR system Part 2 – Protocol optimization: hardware and software Part 3 – Testing of mock crime scene samples Removes inner tube after centrifugation Discussion DNA extraction of crime scene samples involves multiple critical steps. Many labs choose to manually perform DNA lysis and extraction of their precious samples due to concerns about yields and quality. Although large portions of this process have been successfully automated, the most critical steps are still done manually: (1) sample lysis, and (2) subsequent separation of the cleared lysate from the trace carrier. These time-consuming steps have proven difficult to automate, nearly always add gaps in traceability, with high risks of contamination and sample mix-up. They are considered major bottlenecks for most forensic labs. The AutoLys STAR is a fully automated lysis solution designed to overcome these essential crime lab needs. The single instrument platform uses a unique 2D-barcoded AutoLys Tube and can process up to four 24-tube racks at once. It carries out fully automated lysis & separation in a single tube without user intervention. This includes all liquid handling, heated-shaking incubations and centrifugation steps. The AutoLys drastically reduces contamination risk, sample-switching and other user errors. New multifunctional AutoLys Channels are unique to the AutoLys platform. AutoLys, as a walk-away robot, can run unattended overnight without need for assistance. Lysate purification (e.g., using magnetic beads) can be on the same deck or transferred to another system for further processing. The NFI is intensively testing the AutoLys STAR system, performing developmental validation testing prior to its release. Initial validation data show that samples processed using the AutoLys give equivalent or better results than the same samples processed manually. This innovative system is a promising solution for forensic scientists to help process their ever increasing sample numbers while maintaining quality, traceability and maximizing DNA yields.