Automated Purification of DNA from Large Samples: A Study of Effectiveness and Labor Efficiency

Investigations into the underlying genetic contributions to human disease are transitioning from small family-based traditional linkage analyses to large population-based studies designed to identify genetic factors in more complex and common diseases that have the greatest impact on human health. These types of studies have driven the need for larger numbers of samples for analysis and more efficient and effective methods for DNA purification, especially for large samples that provide sufficient quantities of DNA for extensive analysis. The AUTOPURE LS™ Nucleic Acid Purification Instrument, by Gentra Systems, Inc., a platform capable of high-throughput sample purification from large samples, was developed to meet the demands of these large studies. This article presents data demonstrating the equivalency of DNA purified using the AUTOPURE LS automated instrument and the manual method based on the same purification process. In addition, we present data demonstrating the in-lab time savings realized by automating the purification process.     

A Fully Automated High-throughput Nucleic Acid Purification System Using Silica Coated Magnetic Bead Technology

The design of a fully automated high-throughput system for the purification of sequencing templates is described. Hardware, software, and chemistries have been optimized to suit the needs of high-throughput laboratories involved in genome sequencing projects. Using this system, up to 5760 samples (60 x 96-well plates) can be purified in less than 16 hours during a single unattended run. The system can also be configured to perform sequencing reaction setup for all 60 plates following template purification, extending total run times to < 24 hours. Final sequencing reactions are prepared in 384- well microplates.     

Development of an Automated High-Throughput Analytical Characterization System for Support of a Central Sample Collection Resource

A high-throughput analytical characterization system was developed for quality control support of a central sample collection resource. This system utilizes liquid chromatography mass spectrometry with in-house developed data automation applications. Continuous operation of analytical instrumentation is accomplished by fully automating sample submission and report processing functions. Comprehensive analytical information characteristic of quality, chemical, and physical properties (e.g. relative purity, detection sensitivity, LogD) are automatically transferred to an on-line database. The application of this database for detailed quality assessment of a small sample library (ca. 24,000 compounds) is demonstrated.     

Automated High-Throughput mRNA Selection From Eukaryotic Total RNA

We describe a new technology (patent pending) for high-throughput selection of poly(A)⁺ RNA from total RNA. A novel binding solution is used to ensure the efficient and specific binding of mRNA to oligo(dT) magnetic beads with high stringency, virtually eliminating the non-specific binding of ribosomal RNA (rRNA) either to oligo(dT) beads or to the poly(A)⁺ RNA bound to the beads. As quantified by real-time RT-PCR, more than 99% of the rRNA is removed in a single round selection and mRNAs are fully recovered for both highly-expressed (GAPDH) and poorly-expressed (DDPK) genes from a few μg total RNA. The protocol is adaptable to any generic robotic workstation and takes ˜30 minutes to process 96 samples.     

Miniaturization of Sample Processing for Bioassays

LLNL has recently licensed its hand-held advanced nucleicacid analyzer, the HANAA, for commercial development. This (as is characteristic of other miniaturized, portable diagnostic instruments being developed around the world) typically still requires manual sample handling and preparation by skilled operators. Dielectrophoretic and acoustic manipulation of fluids and particles are techniques that have shown good promise to reduce the demands on manual sample preparation both for miniature and for table-top instrumentation.     

A 384-Well, Fully-Automatable, Superparamagnetic-Particle Based Dye Terminator Removal Kit

We have developed a method for the automated purification of DNA sequencing reactions using the RapXtract™ 384 Dye Terminator Removal Kit and the Quadra 3™ Workstation. The process enables purification of 384 reactions in five minutes, significantly impacting the through-put potential of sequencing laboratories. The RapXtract technology utilizes superparamagnetic particles, (i.e., particles that are not themselves magnetic but that respond to a magnetic field) and eliminates the need for centrifugation, vacuum filtration, or modified primers. The Quadra 3 Workstation is a 384-channel liquid handling system, fitted with a retractable magnetic nest designed to incorporate a 384 magnetic separator. The combined technologies result in reduced variability associated with manual methods for sequencing reaction purification.     

Automated High-Throughput Purification of PCR Products Using WizardMagneSil™ Paramagnetic Particles

Here we describe a reagent system and robotic methods for the purification of PCR^(a) fragments from other contaminating amplification reaction components. The methods use the MagneSil™ paramagnetic particle chemistry^(b) to isolate double stranded DNA fragments from 150bp to 23kbp. Purified fragments are eluted in water ready for downstream applications such as cloning, fluorescent DNA sequencing and microarray printing. This method has been adapted to a number of liquid handling robotic platforms, including the Biomek^® FX and Biomek^® 2000 Laboratory Automation Workstations, in both 96 and 384-well formats.     

MagneSil™ Paramagnetic Particles: Magnetics for DNA Purification

MagneSil™ Paramagnetic Particles are silica-paramagnetic particles with an affinity for nucleic acids under defined conditions. Particle structure and solution composition can be altered to selectively adsorb nucleic acids based upon type and size. These properties have been used to develop purification methods based on a three-step bind, wash, and elute process. The MagneSil™ technology is readily adaptable to robotic platforms, allowing complete automation of the purification process in either 96- or 384- well plate formats. This article introduces the basic physical and performance characteristics of the MagneSil™ Paramagnetic Particles.     

Automated Lead Discovery and Development in HTS Datasets

The analysis of biological screening results has traditionally been a labor intensive process. Scientists familiar with the biological data under investigation would visually inspect the results, evaluate the quality and promise of active data points and identify leads. The introduction and widespread use of high throughput screening systems has increased the size of biological datasets immensely thus pushing the traditional analysis method to its limits. In this presentation we describe a new automated approach that emulates the decision making process of human experts. This approach combines knowledge-based techniques with human expertise to enable rapid identification, characterization and prioritization of lead candidates.     

A Fully Automated Process Using a Magnetic Particle Based Kit for Removal of Dye Terminators from Sequencing Reactions

Prolinx,® Inc. of Bothell, WA has developed the RapXtract™ 384 Dye Terminator Removal Kit for full automation of DNA sequencing reaction purification. The RapXtract product line is based upon proprietary superparamagnetic particle technology that eliminates the need for centrifugation, vacuum filtration, or modified primers to achieve purification of sequencing reactions. The kit described here is pre-dispensed in a 384-well microtiter plate and run on the TECAN GENESIS Workstation 150 (Tecan U.S. Inc., Research Triangle Park, NC). This system enables rapid purification of up to 384 sequencing reactions in a single run.As the completion of the Human Genome Project nears, it is imperative for biotechnology and pharmaceutical companies to increase throughput of DNA sequencing in order to be competitive in the drug discovery and validation process. The “race to market” requires a shift from standard DNA sequencing processes-including DNA sequencing reaction purification-towards complete walk-away automation for all steps.Existing sequencing reaction purification methods (Table 1) require considerable resources including: plastic and other laboratory consumables; specialized equipment, such as high-speed centrifuges or vacuum filtration apparatus; and labor-intensive protocols requiring large amounts of technician time. As a result, walk-away automation of standard purification methods is difficult and expensive.     

An Automated System for Processing Sample Vials Stored at Ultra-Low Temperatures

The BIOPHILE Individual Vial Retriever (IVR) system has been developed to provide automated access to vials stored at ultra-low temperatures. The IVR performs storage, retrieval, sorting, cataloging, volume estimation (weighing), barcode reading, and re-racking. All racking operations are performed in an environment designed to keep samples frozen at their optimal temperature. Operating temperatures are −80°C, −40°C, −20°C, and room temperature. Laboratory Information Management System (LIMS) integration, automation integration, chain of custody tracking, and FDA 21CFR Part 11 compliance are supported. This article introduces the IVR and provides information on its characteristics.     

Incorporating Automation in Undergraduate Laboratories

Automated techniques and philosophies, which have become increasingly important in modern laboratories, are not traditionally covered in undergraduate chemistry curricula. To this end, we have been incorporating automated sample preparation methods using standard robotic workstations in our undergraduate analytical chemistry laboratory. Using a Benchmate™ II Workstation, an automated method has been developed and implemented for the solid phase extraction of capsaicins from commercial hot pepper sauces prior to liquid chromatographic analysis. This paper reports on pedagogical aspects of incorporating automation into the undergraduate curriculum as well as results obtained for manual and automated extractions conducted by students.     

Automated Purification of Plasmid DNA Using Paramagnetic Particles

We describe a reagent system and robotic method for purifying plasmid DNA for restriction digestion, PCR, and fluorescent sequencing applications. The method uses two types of Wizard® MagneSilTM paramagnetic particles. Following lysis and neutralization procedures, the first particle type binds and removes cell debris; the second type is then used to bind plasmid DNA from the cleared lysate. The particles are then washed to eliminate unwanted contaminants. Purified plasmid DNA is then eluted from the particles with nuclease free water. When using a cell mass of approximately 4 O.D.₆₀₀, the yield is 10–12μg of DNA when using high copy number plasmid. When used in BigDye® terminator sequencing, these DNA templates typically yield read lengths greater than 700 bases and Phred 20 scores of 600 to 750 bases. This purification method has been adapted for use on several robotic platforms in a 96-well format.     

Multiplex SNP genotyping using Locked Nucleic Acid and microfluidics

Locked Nucleic Acid's or LNA are a new class of bicyclic DNA analogues that have a high affinity and specificity towards complementary nucleic acids. LNA containing oligonucleotides were used to develop a multiplex SNP genotyping assay based entirely on hybridization between capture probe and target. The approach incorporates a polymer microarray platform, photochemistry for immobilization of oligonucleotides onto microarrays, and a dedicated software tool to aid primer and capture probe design for highly multiplex genotyping. Furthermore, these technologies are combined in an integrated microfluidics platform for simple, highly multiplex and robust SNP genotyping.     

Automated Lab-on-a-Chip Analysis of DNA Fragments

The design of a fully automated system for the analysis of DNA fragments in 96-well plates is described. Microfluidic technology is used to integrate sample loading, electrophoretic analysis, and fragment detection onto a miniature lab-on-a-chip device. The microfluidic chip operates in an instrument platform that automates sample access, data collection, and data reporting. Each microfluidic chip provides sizing and concentration values for more than 1000 DNA samples.     

Determining Feasibility and Parameter Values for Compound Orders Based on Transfer Amounts, Liquid Handler Capabilities, and Container Volume Capacities

An algorithm is described for determining feasibility and calculating parameter values for one or more compound processing orders. Feasibility is determined primarily by applying a series of inequality constraints that result in a valid target concentration range within which orders can be processed. These inequality constraints are obtained from initial compound amounts, source and destination container volume capacities, the liquid handler transfer volume range, and the amount of compound to be processed. If feasible, calculated parameter values include the dilution, transfer and top-off volumes necessary to fulfill the order. Sample code implementing the algorithm is given in Microsoft Visual Basic®.     

HTS Automation Study: Results from a 2001 Survey of the Current vs. Desired State of HTS Automation

A survey of directors of screening organizations was conducted in 2001 to evaluate their perceptions of the current vs. desired state of high-throughput screening (HTS) automation. The survey encompassed attributes such as automation flexibility, throughput and operation. These and other automation attributes were ranked based on importance to the respondent and/or the limitations these attributes imposed on the screening organization.     

Optimizing Reaction Conditions of the NanoOrange® Protein Quantitation Method for Use With Microplate-based Automation

Because of the rapidly expanding need for higher sample throughput in drug discovery, automation of corresponding biochemical analyses is desirable. In particular, automation of protein quantitation is crucial since its results are used extensively. Recently, a single-reagent fluorescent protein quantitation method (NanoOrange®) with attractive performance attributes has become available. While it can potentially be automated with liquid handling workstations, several of this method's reaction parameters need to be optimized.

We studied the time and a temperature dependence of the NanoOrange protein quantitation reaction in ninety-six well black microplates using either a temperature-regulated hot block or a microwave oven as heat sources. Fluorescence of the NanoOrange reaction was quantified with a multimode microplate spectral scanner.

Time-dependent heating profiles of filled microplates placed on hot blocks at fixed temperatures (45, 55, 65, 75, and 95°C) revealed temperature differences of 4–7°C cooler for the outside wells compared to the inner wells, however the maximum well temperature did not exceed 65°C. Similar time-temperature studies of microwave-heated microplates revealed an equilibrium temperature of 45–49°C that was 10–16°C lower than microplates that were block heated.

The bovine serum albumin (BSA): NanoOrange standard curves created using a hot block increased in slope from 45°C to 55°C, but then remained constant from 65 to 85°C.

Fluorescence of the BSA: NanoOrange standard curve created using a microwave oven was about half the magnitude of the hot block-derived curves, possible reflecting a lower energy transfer rate of the microwave oven. We conclude that the NanoOrange protein quantitation method can be automated if a microplatecompatible hot block with a 65-85°C surface can heat the microplate for minimum of 15 min prior to quantifying the reaction's fluorescence.