Molecular biologists rely on DNA and RNA to advance genetic research, support forensic investigations, develop vaccines, and more. For accurate results, these nucleic acids must be carefully isolated from cells and purified. Here are some factors to consider in choosing the right pump for your nucleic acid sample preparation device, so you can ensure it’s as up to code with your needs as the genetic codes placed into it.
Sample Preparation Process
1. Isolation
The process begins with cell lysis, where cell membranes are broken down to release the nucleic acids, isolating them from the other cellular components. This is usually accomplished using a lysis buffer solution containing chemical agents (i.e., detergents or chaotropes) and/or enzymes (i.e., lysozyme). Other times, a physical disruption method is used.
2. Purification
Once cell lysis is complete, the nucleic acids are then purified to eliminate proteins, lipids, and contaminants using one of the following techniques:
• Organic Extraction - phenol-chloroform separates nucleic acids into an aqueous phase (top layer) while moving the proteins and lipids into the organic phase (bottom layer)
• Column-Based Extraction - binds nucleic acids to a silica matrix to allow for washing away of contaminants (i.e., using spin columns/centrifuges)
• Magnetic Bead-Based Based Extraction - magnetic beads coated with binding molecules selectively capture DNA/RNA from the sample
3. Precipitation
Lastly, adding salt and alcohol (usually ethanol or isopropanol) precipitates the nucleic acid from the purification solution. This makes it usable for downstream applications like PCR or genetic sequencing.
OEM Pump Necessities
1. Chemical Compatibility
Nucleic acid preparation involves the use of reactive and often corrosive chemical reagents such as sodium dodecyl sulfate, guanidinium thiocyanate, and others. This requires resistant internal pump materials, like Fluid Metering’s chemically inert CeramPump® technology, to save the OEM device from degradation and to prevent samples from becoming compromised.
• Flushing Capability - DNA and RNA are highly susceptible to contamination during cell lysis due to:
• Leftover Proteins - cellular proteins, including nucleases (DNases and RNases), can remain in the sample and degrade nucleic acids if not properly removed
• Environmental Contaminants - DNA or RNA from the environment like skin cells, dust, or airborne particles can mix into samples during handling
• Chemical Residuals - chemicals used during the extraction process can persist if the sample isn’t thoroughly purified
• Cross-Contamination - using the same equipment (pipettes, tubes, etc.) without thorough cleaning can cause sample-to-sample contamination
Some pumps lack flushing capabilities, so they require an additional pump to flush the lines. Others that are self-flushing, like certain syringe pumps, require excessive cycle downtime to do so. To solve these issues, Fluid Metering’s FENYX Variable Dispense provides priming, dispensing, and flushing all within the same fast-paced cycle for efficient use in high-throughput sample prep.
3. Flow Rate & Volume Range
The microscopic size and delicacy of nucleic acid samples requires the handling of small volumes of liquid at low flow rates. Selecting a pump that offers a suitable flow rate selection helps to prevent sample damage and shearing by exerting lower pressures. Fluid Metering Pumps are excellent choices for microliter dispensing at programmable flow rates. In particular, the FDD Pulseless Nanoliter pump provides resolution down to the nanoliter scale. To achieve high throughput without compromising on volume or flow rate settings, consider using a pump that can use multiple lines simultaneously, such as the Duplex pump.
4. Reliability, Automation, & Integration
When working with nucleic acids, even the smallest deviation in liquid volume can lead to inconsistent results, so it’s essential to look for a pump that offers high accuracy and precision to ensure every drop is delivered as intended. Due to the nature of their operation, certain technologies like peristaltic pumps, positive pressure pumps, diaphragm pumps, gear pumps, and centrifugal pumps can contribute to worsening contaminants and residuals. Their tubing compression, excess pulsations, and pressure limitations can lead to inaccurate chemical dispenses, preventing proper results. These risks are highly decreased in Fluid Metering pumps where tubes are never compressed and pulsation is minimized. It also results in consistent dispense accuracy and the maintenance of 0.5% precision for millions of cycles, saving loads of time and money in the long run.
Fluid Metering pumps can also be easily integrated into new/existing automated workflows and controlled by their included software. While manual prep is possible, the lab automation that microfluidic pumps create expedites the processes and greatly minimizes the risk of human errors.
Prep to Perfection
Selecting the right pump for nucleic acid sample prep is not just about meeting technical specifications - it's the DNA that forms the integrity of molecular biology research. By carefully considering factors like chemical compatibility, flushing capabilities, and flow rate, you can ensure your OEM device is optimized for success. Contact us today to receive expert engineering support in achieving your desired results.