The Ultimate Purchasing Guide to Thermal Cyclers

What are PCR Thermal Cyclers?

Thermal cyclers come to mind while thinking of DNA/RNA analysis in molecular biology. Thermal cyclers (also known as PCR machines or thermocyclers) are scientific instruments for replicating, analyzing, detecting, and amplifying DNA or RNA segments. They're also employed to make quick diagnoses and limit enzyme digestion. Thermal cyclers are essential for the proper operation of relevant laboratories; without them, operations would come to a halt. Before purchasing a thermal cycler, think about what you want to get out of it. Before purchasing a thermal cycler, there are few aspects to check for. This article serves as a guide to assisting you in finding a thermal cycler that meets your needs.

To figure out which thermal cycler to get, you must first grasp how a thermal cycle works. The temperature of the DNA/RNA combination is controlled using a thermal cycler that follows pre-programmed instructions. The heat-generating thermal block has holes for tube installation. The temperature instruction is set after the samples are put within the tube and inserted into the hole. The capacity of a thermal cycler to maintain and change temperature at a precise time based on programmed instructions is its most important feature (instructions can be set through a computer, the machine itself, or using pre-programmed instruction).

Thermal cyclers are used in research labs to amplify and replicate a specific DNA sequence, forensic labs to identify a DNA sequence in fingerprints, bodily fluids, and other samples, and diagnostic centers to detect genetic sequences and diseases, as well as harmful DNA/RNA in the body.

How Thermal Cycling Works

Thermal cycling, a heating and cooling procedure that produces the conditions for DNA replication, is used to carry out the actual PCR process. Denaturing, annealing, and extending are the three steps of PCR thermal cycling.

  1. Denaturing - Denaturing is the first step in the PCR heat cycling process. This warms the DNA sample to the point when the double-stranded sample separates into two separate DNA strands.
  2. Annealing - After the initial denaturing heating, the temperature is decreased to allow the DNA primers to connect to the sample DNA by annealing.
  3. Extension - Extending entails an additional temperature gain. The Taq polymerase enzyme is able to duplicate the template DNA after this last temperature rise.

The heat cycling procedure is done between 20 and 40 times for each of these three stages. Each subsequent cycle doubles the number of DNA copies. The amount of time spent on thermal cycling varies based on the size of the sample and the equipment utilized, but it usually takes between one and four hours. Electrophoresis may be used to examine the samples and conduct further studies after heat cycling.

What are the Elements of a Good Thermal Cycler?

There’s no cut-and-dry way to explain what a “good” thermal cycler. It all comes down to your unique application, and it helps to understand what kind of thermal cycler you’re looking for from the get-go.

The aims of your application are critical in determining the best PCR equipment for your lab. Examining what it requires of you and imagining the changes your lab could face in the future might help you limit down your options. Begin by answering the following questions:

Product Type

You can acquire a traditional endpoint PCR, a qPCR, or a digital PCR equipment, depending on your ultimate aim. A conventional thermocycler can be used for simple operations such as producing nucleic acid sequences for sequencing, cloning, or monitoring reactions on a gel. You may look into qPCR models instead if you're interested in real-time quantification of a DNA target sequence or assessing the presence of biomolecules like mRNA or polymorphism rather than generating an end product. A digital PCR thermocycler, like a qPCR, allows for DNA quantification but not in real time. The reactions take place in a large number of tiny partitions, each of which is expected to contain just 0 or 1 DNA molecule, resulting in a more sensitive quantitative DNA measurement than a qPCR unit and without the need for a standard curve.

Sample Throughput

You should also think about the sample throughput you expect. Although digital PCR thermal cyclers have superior sensitivity and discrimination than qPCR thermal cyclers, keep in mind that their throughput is restricted. You can get smaller, personal cycling systems that can run up to 48 samples at a time if you only need to work with a few samples every now and then.

Consider qPCR cyclers, dual 48/48 well thermal cyclers, multi-bay cyclers, and quad cyclers for routine high-throughput work. You may also purchase PCR devices that can process up to 96 samples at once. Consider not only your present throughput requirements, but also your future application demands when purchasing thermocyclers that may be networked with other units for increased throughput.

Temperature Change

A thermal cycler should change the temperature quickly, hold it for a set amount of time, and then change it again. While this is desirable, not all thermal cyclers have the ability to adjust temperature in real time. Before changing the temperature of the content, certain thermal cyclers modify the temperature of the tube's surroundings. While most laboratory experiments need the quickest temperature change, certain investigations may be completed with a slower shift. As a result, when purchasing a thermal cycler, make sure the temperature change is as rapid or as slow as you require. Thermal cyclers with a silver heating block are used for a quick and uniform transition. Because silver is a good heat conductor, it may start a temperature shift as fast as feasible.

Sample Capacity

When choosing a thermal cycler, sample capacity is also an important factor to consider. The sample capacity of a thermocycler machine refers to the number of sample tubes it can hold during a single cycle of operation. The kind and size of individual tubes that the thermocyclers can handle are also factors in sample capacity. While thermal cyclers that employ 0.2ml PCR tubes are common, additional thermocyclers with other tube sizes are also available. Thermal cyclers with a single plate of holes, numerous plates with the same tube type, and multiple plates with various tube sizes are available, depending on how many sample tubes you wish to examine each time. Consider the sample capacity you'll need, as well as the size and kind of sample bottles you'll be using, before purchasing a thermal cycler. When choosing a thermal cycler, keep in mind future sample capacity growth and use goals.

Oil vs Heated Lids

Thermal cyclers cause the sample fluid in the sample tubes to evaporate and condense due to their heating and cooling effects. The concentration of reagents changes as a result of evaporation and condensation, which affects the data and results of the PCR test. Thermal cyclers come with either a mineral oil to top the reagents in the tube or a heated cap to prevent this. The heated lid is simpler to use than the mineral oil, which may be messy and difficult to deal with in a hurry. With newer kinds of thermal cyclers, there are also advancements in the heated lid. Choose between a mineral oil-based thermal cycler and a heated lid. Consider the sort of heated lid that each thermal cycler comes with, as well as how advanced it is.

Overall Costs

When purchasing a thermal cycler, your budget should be a primary factor. Choose a machine model that meets your needs while staying inside your budget. Thermal cyclers with more technical innovation are more expensive than those with less. When selecting a thermal cycler, keep your budget in mind.

Top PCR Thermal Cyclers to Buy Today

MultiGene Mini

The MultiGene Mini is a small and light thermal cycler, but don't be fooled by its little size. This cycler has a lot of functions that are usually only seen on bigger thermal cyclers. A 24 × 0.2 ml tube block or an 18 x 0.5 ml tube block are offered for the MultiGene Mini. The blocks may be swapped out quickly. An adjustable heated lid is standard on all units. A slide gear is included inside the lid to provide appropriate compression and prevent sample evaporation without deforming the tubes.

MultiGene Optimax Thermal Cycler

The new MultiGene OptiMax thermal cycler replaces our popular and dependable MultiGene Gradient model and adds additional speed and sophisticated capabilities to our Labnet Thermal Cycler range, delivering superior performance at a low cost. The MultiGene OptiMax heats at 4 degrees Celsius per second and cools at 3 degrees Celsius per second. Overshooting and undershooting have been reduced in the product, ensuring that your reactions only see the temperatures that they should. This also results in a shorter run time.

TC-32 Mini Thermal Cycler

The TC-32 Mini Thermal Cycler from Benchmark has the same comprehensive programming options, easy-to-use software, and rapid, dependable cycling as the bigger TC-9639 Thermal Cycler, but with a smaller block and cheaper price. The TC-32 Mini Thermal Cycler has a capacity of 320.2ml tubes and is designed for reduced throughput demands. The wells are organized in a 48-well arrangement, which allows the block to accommodate both strips of 8 and individual tubes. The TC-32 Mini Thermal Cycler fits nearly anywhere, with a footprint less than that of a typical laboratory notebook.

TC9639 Thermal Cycler

For laboratories with medium to high throughput, the TC9639 Thermal Cycler delivers consistent and dependable results. This cycler is packed with features, from its distinctive multi-format block to its huge, touch-screen user interface. The program wizard and ten preconfigured apps make getting started easier than ever. There is no need to spend money on many interchangeable blocks when using the multi-format block. The TC 9639 can accommodate 96 x 0.2ml tubes, a 96-well plate, or 39 x 0.5ml tubes in the same sample block. For usage with slides, an in-situ adaptor is offered. A 384-well sample block is also available for purchase with the equipment.