Polymerase chain reaction (PCR) machines are cost-effective and highly efficient tools used to amplify small segments of DNA or RNA that are selected from the genome using a primer.
Also known as PCR systems, thermal cyclers, or thermocyclers, these devices combine the principles of nucleic acid replication with complementary nucleic acid hybridization to exponentially produce specific target DNA/RNA sequences by a factor of 10 7 within a matter of hours.
The PCR technique, invented by Kary Mullis, works by binding primers to the target sequence and extending this using a Taq polymerase (thermus aquaticus). The basic steps of conventional PCR are broken up into three stages, however, a huge variety of modifications exist.
Because of their ubiquity and power, PCR systems are sought-after by countless scientists, researchers, and technicians, across a wide range of studies, including viral infection testing such as the SARS-CoV-2 virus of the COVID-19 pandemic.
Furthermore, the option to lease these machines makes them accessible to both biotechnology start-ups and enterprise companies.
What Does a PCR Machine Do?
A PCR machine, which is more commonly referred to as a PCR system, is used to make millions of copies of an initially small segment of DNA.
This process is also sometimes referred to as “molecular photocopying”. It allows scientists to amplify DNA enough to study in detail, making it an incredibly valuable piece of equipment in both clinical and research settings.
Amplification is required because a single piece of DNA is nearly impossible to work during molecular and genetic analyses. In order to amplify the DNA into millions of copies, PCR amplification is required.
The amplified DNA produced by PCR has a variety of uses, including the investigation of genetic diseases, DNA fingerprinting, and the detection of bacteria or viruses. For this reason, PCR is an integral part to biomedical research and criminal forensics.
How Does It Work?
Research and advancements in the life sciences wouldn’t be possible without PCR, as it has already greatly contributed to a number of innovations. In fact, its introduction is considered to have revolutionized molecular biology, changing how scientists were able to study DNA going forward. Its history rich and impactful despite only being developed around 40 years ago.
The polymerase chain reaction process is spread across three steps, with the assistance of five essential reagents. The steps include:
The five essential reagents include:
- DNA template
- DNA Polymerase
- dNTPs(Deoxynucleotide triphosphate)
- PCR Buffer
After the initial denaturation is performed, the three main steps are repeated until millions of copies of a target DNA sequence exist.
Types of PCR Machines
In addition to the standard methods of PCR, several modifications have been developed. By altering how PCR machines operate, they can now be used for a wider variety of applications. Some of the most common types of PCR are:
1. Conventional PCR machine
The conventional polymerase chain reaction is used to amplify a target DNA sequence to several million in a short amount of time, usually in just 2-3 hours. It allows the replication of cellular genetic material using a polymerase enzyme to construct specific fragments of DNA.
The polymerase enzyme works alongside a primer which is connected to a strand of DNA, allowing for the synthesis of specific parts of the DNA strand. The result of using primers in this way is the amplification of a chosen DNA sequence, up to millions or billions of copies.
Conventional PCR is used in many areas of study, including medical and diagnostic research, forensic studies and research, selective DNA isolation, amplification and quantification of DNA.
Quantitative PCR (qPCR), also called real-time PCR, or RT-PCR, is a variation of the standard polymerase chain reaction which uses just one machine to combine the amplification of a target DNA sequence with the quantification of the concentration of the DNA in any given reaction. This is done using fluorescence-detecting thermocyclers.
Compared to conventional PCR, qPCR provides a faster alternative to facilitate analysis by detecting products in real-time during the exponential phase. Fluorescent dyes signal DNA of interest, and the amount of fluorescence generated is determined by the quantity of DNA present.
There are various models of real-time PCR available, but they all have common features: a standard thermal cycler platform coupled with an excitation source (usually a laser or tungsten lamp), a camera for fluorescence detection, and computer and software for data processing.
qPCR can be used in genotyping and quantification of pathogens, microRNA analysis, cancer detection, microbial load testing and GMOs detection.
3. Reverse Transcription
Reverse Transcription PCR (RT-PCR) is a variant on conventional polymerase chain reaction which amplifies target RNA. The addition of reverse transcriptase (RT) enzyme before PCR means it is possible to amplify and detect RNA targets.
During RT-PCR, RNA molecules are converted into complementary DNA (cDNA). Single-stranded cDNA is converted into double-stranded DNA using DNA polymerase. The resulting DNA molecules can then be used and amplified in a PCR reaction.
RT-PCR is used in gene insertion, research methods, genetic disease diagnosis and cancer detection.
Nested PCR is a modification of PCR where non-specific binding is prevented to increase the sensitivity and specificity of the reaction. Nested PCR works by having the first set of primer bind to the outside of the target DNA and amplifies a larger fragment, while a second set of primer binds specifically at the target site in successive PCR reactions.
Nested PCR is great for use in phylogenetic studies and in the detection of different pathogens. This is due to the higher sensitivity brought by Nested PCR compared to conventional PCR. Even if a sample contains lower DNA, Nested PCR allows this sample to be amplified.
5. Hot Start
Hot start PCR is a new form of the conventional polymerase chain reaction which reduces the occurrence of undesired products and formation of primer-dimers due to non-specific DNA amplification at room temperatures.
This works by keeping the different elements of the reaction separate until the mixture reaches the denaturation temperature after heating.
Hot start PCR can often increase product yields in comparison to conventional PCR. It also requires less effort than conventional PCR and reduces the risk of contamination.
6. Digital (dPCR)
Digital PCR devices, or dPCR, are the most accurate devices on the market. They provide absolute counts of target DNA with enhanced increased sensitivity, precision, and reproducibility. Digital polymerase chain reaction is poised to disrupt molecular analysis technology on every level. There are two types of dPCR machines:
- Droplet Digital PCR (ddPCR): ddPCR uses Taq polymerase to amplify targeted DNA in a complex sample. To simplify the processing, ddPCR emulsifies samples in oil and uses fluorescence to process and analyze the results. Before analysis, the sample is divided into droplets and thermocycled, then run through a 96 well PCR plate. This separation process is the primary difference between ddPCR and qPCR
- qdPCR: The qdPCR process is based on integrated fluidic circuits (chips). While chip-based techniques have a narrower dynamic range, they provide extremely precise sample partitioning and vastly lower variance.
On the forefront of detection technology, ddPCR and qdPCR are top-of-the-line processing machines with a high price tag to match. Fortunately, it’s cheaper to lease.
How Much Does a PCR Machine Cost?
The cost of a PCR machine can vary enormously depending on your needs. A basic PCR machine can have as low as a $5,000 list price, while top-of-the-line RT-PCR or qPCR systems can range from $15,000 to over $90,000.
It doesn’t stop there, either. When you include the hidden costs of a PCR machine, such as running experiments, you’ll see that the total cost extends well beyond that purchasing price. Because these costs are far less obvious when spread out over years, they can make a big difference.
So, remember to consider not only the cost of the model you’re interested in, but the cost of the reactions as well. Doing so will give you a better idea of how much a PCR machine will cost you over time, and when exactly you could break even.
With all this in mind, the prohibitive costs of this defining technique in molecular biology makes PCR systems inaccessible for any facility on a limited budget. If you’re in the market for a high-end PCR machine and constrained by your budget, considering leasing as an option to purchasing outright.
Leasing vs. Buying PCR Machines
There are a number of advantages to leasing a PCR machine through Excedr compared to purchasing. Here are just a few highlights:
- Minimize upfront costs: payments are 100% tax deductible operating expenses. This means leasing is significantly less expensive than purchasing upfront.
- Manageable, flexible payments: Depending on your financial needs, you can pay either monthly or annually. Having predictable, low payments makes monitoring and managing cash flow notably simpler
- Benefit from included comprehensive service plans: You don’t need to buy or worry about annual service contracts. In fact, all repairs and maintenance are covered in the lease
Furthermore, leasing is much faster and straight forward when compared to other traditional forms of financing, such as bank loans and a line of credit.
Our leasing program—which involves less paperwork and doesn’t require the same collateral the bank asks for—allows you to move quickly. With the money and time you save by leasing lab equipment, you can invest in your core business, hire more people, get your product to market faster, and put more dollars into marketing.
Contact us today to equip your lab and stay under budget.