How to Choose the Right Tube Format for Thermoshaker Workflows 

Thermoshaker has now become essential in the fields of modern biology, chemistry, and molecular workflow as it provides a combination of controlled heating, cooling, and stirring in one device. Still, even the most modern laboratory thermoshakers will fail to provide the best performance when the tubes employed in the working process are not optimized to the task. 

This article disaggregates the critical factors that assist researchers in making informed, practical decisions on tube format selection to be used in thermoshaker use.

Think About What You’re Mixing or Incubating

Begin with the use of the tube before choosing it. The behavior of various types of samples in the process of shaking and heating is highly different.

• Viscous samples (e.g., cell lysates, dense extracts of proteins, etc.): Use tubes with tight caps and a distinct amount of space between the two that would enable the tube to be agitated without spilling over. Larger tubes, e.g., 1.5-2.0 mL micro tubes, tend to improve mixing efficiency.

• Biological reagents (enzymes, DNA, RNA) that are sensitive to heat: Tubes with good thermal uniformity and low thermal lag. Here, thin-walled PCR tubes or 0.25 mL to 0.5 mL tubes prove to be better.

• Solvents that are volatile or otherwise strong: Request chemical-resistant plastics or special tubes used with organic solvents.

• Cell suspensions or pellets: Use of tube formats, which allow a uniform generation of the vortex during shaking, eliminating the uneven resuspension.

• Long incubations or a cycle of temperature: Demand tubes that do not leak with time to eliminate evaporation or changes in concentration.

The tube format selection is determined by the sample and not the opposite. It is much easier to clarify what you are mixing or incubating, and then all other decisions become very easy.

Know the Standard Tube Formats You’ll Encounter

70% of investigators are unable to replicate previous laboratory blocks due to inconsistencies. This knowledge of laboratory tube types and their purpose ensures that you do not take too long to choose the appropriate one and provide accurate results from testing. 

• 0.2 mL PCR tubes or strips: Best used in high heat transfer rate, low reaction volume, and temperature-sensitive processes.

• 0.5 mL tubes: Applicable in moderately sized volume reactions that require rapid cooling and heating, but must be more stable than PCR tubes.

• 500 ul and 100 ul microcentrifuge tubes: The most popular type of mixing, incubations, enzyme reaction, protein assay, and nucleic acid prep steps.

• 5 mL snap-cap tubes: Offer increased working volume with compatibility with numerous thermoshaker blocks.

• 15 mL and 50 mL conical tubes: Even more rarely used on thermoshakers except when dealing with special blocks. 

• Deep-well or deep-well compatible microplate tube strips: Authorized to be used with high throughput workflows, automation, or batch incubations.

Being aware of these formats may assist in guaranteeing that the tube you pick out matches the thermoshakers as well as your volume of work needs.

Match the Tube to Your Thermoshaker’s Block Design

The best tube will not work in situations where it does not interface well with the thermoshaker block.

• Measures the external measurements of the tube

• Use the correct block insert

• Selection of blocks with lids, when it comes to working with temperatures

Other thermoshakers (such as IKA) may use quick-swap block systems, such that when you change format, you do so without interrupting workflow. Matching tube and block design provides consistent, repeatable, and predictable thermal performance.

Consider How the Tube Material Influences Outcomes

Not all plastics respond to heat and shaking. The material of the tube affects the behaviour of the reaction more than most users care to admit.

• Polypropylene (PP): Microtubes are mostly made of this material. Exceptional chemical capability, suitable for most biological operations, and works effectively at moderate conditions of heating.

• Thin-walled polypropylene: Intended to facilitate rapid heat exchange – best in PCR and qPCR, or any other reaction that needs to be done at a specific temperature.

• Polyethylene (PE): More flexible and less heat-resistant. Unfrequently used in thermoshakers because it can become deformed.

• Specialty plastics: There are also organic extractions that may use fluorinated polymers or solvent-resistant plastics to prevent softening of tubes or leaching of chemicals.

• Tubes: (clear versus amber versus opaque):

• Crystal tubes: most suitable for visual monitoring.

• Amber tubes are used to cover light-sensitive products.

• Opaque tubes: of interest to fluorescence-reactive reactions.

The thermal response, chemical compatibility, and overall integrity of the reaction are influenced by the material used in the tube.

Workflow Efficiency and Lab Practicality

Laboratory tube types also affect the day-to-day lab activities. A scientifically admirable tube that introduces friction to the working process wastes time and increases the risk of error.

• Labeling surface

• Ease of opening and closing

• Pipette compatibility

• Batch consistency

• Evaporation control

• Stability of the cost and supply chain

The only true right format of a tube is the one that allows performance in experiments as well as efficiency in the workflow.

Key Takeaway

The choice of the optimal tube format to use in thermoshaker workflows is a series of deliberated-upon choices depending on the nature of the sample, sample volume, compatibility with blocks, tube material, and lab usability requirements. The correct option enhances the mixing, maintains a uniform heating process, endorses reliable outcomes, and minimizes the chances of workflow congestion.