Since the outbreak of the COVID-19 global pandemic, more than 2 million people have been infected across the globe. The highly contagious virus attacks the human lungs and causes respiratory distress. It is spread by coming into contact with people that are affected, or with surfaces that have been touched by an infected person. This had previously not been seen in humans, and there is no known cure for it. At the moment, scientists are trying to find a vaccine for it. This disease is of zoonotic origin and is thought to have jumped species from animals to human beings.
A virus is a microscopic organism that cannot live or reproduce on its own. This microorganism contains DNA or RNA (nucleic acids) strands in their genetic composition. A virus tends to be one of the smallest organisms. Bacteria and other microorganisms are much bigger than a virus. The virus has no way of surviving for a long time on its own and has to rely on a living host to thrive.
Viral replication takes place in six different phases, and it causes significant damage to the cell. First, the virus attaches itself to the wall of a cell. After this, it injects its DNA or RNA material into the cell. The nucleic acid enters the cell on its own, leaving the viral coat behind. This action, in most instances, happens when a cell envelops the virus. This step is the uncoating. After this has occurred, replication and assembly take place. In these stages, the virus DNA/RNA self-incorporates into the cell’s genetic makeup, compelling it to replicate the viral genome. In the release stage, the newly replicated virus genome leaves the cell by three means. The virus can wait for the cell to die off, and it can leave by permeating the membrane or by causing the cell to break apart. When these stages are complete, the victim begins to experience signs and symptoms of an infection.
In the case of COVID-19, a patient can stay from 2-14 days before they start exhibiting symptoms. Different people tend to react differently to the virus. Some cases have reported mild symptoms, while others have shown extreme reactions. All people are susceptible to this virus, and some have a higher risk of infection. People with pre-existing conditions such as heart disease, liver disease, renal failure, diabetes, hypertension, and weak immunity experience severe cases, and some eventually die.
Due to the threat posed by the pandemic, there is a need for testing to determine the number of infected victims. These people are advised to stay in isolation to avoid passing the highly contagious disease to uninfected persons. Testing tools have been important aspects of this exercise. Fast and accurate equipment is needed for the timely diagnosis and management of COVID-19.
Several testing tools have been used to determine the number of infected persons. The PCR (Polymerase Chain Reaction) machine has been of great significance in his exercise. It uses the principle of genetic tracing and amplification of DNA and RNA strands located in liquid surfaces. This machine takes advantage of the fact that every living organism has DNA or RNA strands that are unique to them. This testing makes it easy to determine the identity of the microorganism being studied.
What is a PCR Machine?
Also known as a Thermal Cycler, a Polymerase Chain Reaction machine works by amplifying or copying small parts of DNA. The replicated components are then studied to identify the microorganism being investigated. It is an effective and inexpensive method and contributes a lot to the medical fields of research and diagnostics. It was created by a chemist Kary B. Mullis in 1985 and has since been used widely in medicine.
There are different types of PCR machines, and each works differently, but the results obtained are the same. Some of them are listed below.
- Reverse Transcription PCR – It uses an enzyme called reverse transcriptase to amplify RNA into DNA. This method can be done within the same test tube, which helps in the maintenance of constant conditions of temperature and other environmental factors.
- Quantitative PCR – This is also known as Real-Time PCR, and it works by determining the amount of DNA being produced over time, which helps scientists assess the amount of DNA within a collected sample.
- Nested PCR – This PCR aims at determining the number of errors being made during DNA amplification. Two sets of primers are used in this method. The first one attempts to make a longer than the required strand of DNA. The second set is then nested in the targeted region of amplified DNA. This method ensures the specificity of DNA amplification.
A primer is a single strand of DNA or RNA that serves as the initial foundation for DNA amplification.
- Multiplex PCR – It is used when you need to amplify several sequences within the same sample. Several primers are used in this method.
- Assembly PCR – This method stitches several short strands of DNA together to form large strands of DNA that are connected.
- Host-start PCR – This method uses a technique that heats the reaction components to the DNA melting point before adding the polymerase.
- Digital Polymerase Chain Reaction – In this method, thousands of samples are amplified at the same time within an emulsion, each in a separate droplet.
- COLD PCR (Co-amplification at lower denaturation temperature-PCR) – It is a single-step amplification method that enhances both known and unknown alleles irrespective of their position or type.
An allele refers to one of the forms of a gene. An example is the height gene. An organism can be tall or short, and one of the alleles is dominant while the other is recessive.
- Suicide PCR – This method prioritizes the specificity of a fragment of DNA. Only one primer combination can be used, so long as it has not been used before in any positive control reaction.
- Colony PCR – In this method, bacterial colonies are screened directly by PCR.
There are many other types of PCR methods used in DNA and RNA amplification.
How does PCR Machine work?
In the past, cloning of DNA segments was done in the sectors of interest for expression in bacteria. This method was lengthy and would even take weeks. However, this testing method has seen significant improvement as it takes place in test tubes and is complete within a few hours. Numerous amplification of DNA can also be done, making the method highly efficient. PCR also conveniently uses the same aspects that nature does in DNA replication. They are presented with the molecular form.
- Two primers – Short strands of DNA that act as the base or foundation for amplification
- Enzymatic polymerase – Studies the DNA segment for its code and creates copies of the same.
- DNA building block – They are the site used by the polymerase to create the DNA copies.
What are the four main steps of PCR?
The PCR process takes place in 4 significant steps.
Step 1: Denaturation by heat
Temperatures higher than 90 degrees Celsius are introduced to denature or break down the DNA strands into single strands. The heat breaks the hydrogen bonds that hold the DNA strands together. The heat, however, does not affect the bonds between deoxyribose and phosphates since they are stronger.
Step 2: Annealing the Primer to target sequence
The heated mixture is allowed to cool to about 54 degrees Celsius. The DNA primers and polymerase bind themselves to individual DNA that is in single strands. This process is known as annealing.
Step 3: Extension
Since the DNA blocks are in high concentration, the polymerase uses them to build new strands of DNA. These new strands are referred to as complementary DNA. The temperature of the mixture is raised to 72 degrees Celsius. This temperature range causes the extension process to happen more rapidly. New DNA strand molecules are made from the original single-strand DNA.
Step 4: End of the first cycle.
After the extension occurs, the first cycle comes to an end. This is followed by a repetition of the process from 15 to 40 more cycles. The amount of DNA doubles after each annealing and extension cycle. This could mean an amplification of the initial single-strand DNA samples to up to 40 billion DNA molecules. This process can take 2-4 hours from start to finish.
What diseases can PCR Machine detect?
PCR can detect a wide array of viral, protozoan parasites, and bacterial agents that cause infections. Some of these agents include HIV, HPV virus, Plasmodium falciparum that causes malaria, and bacillus anthracis that is responsible for anthrax.
One of the main characteristics of cancer cells is the constant mutation of the genes. PCR can determine a patient’s response to medication in the long run. This method can also be used to monitor the population of cancer cells in a leukemia patient’s blood.
Genetic diseases and Paternity tests
This particular testing method is the most convenient for any genetic disorder detections. Some conditions that can be diagnosed include sickle cell anemia, dwarfism, albinism, cystic fibrosis, and muscular dystrophy.
How does PCR help in COVID-19 diagnosis?
When a mucus sample containing the virus is collected, it is passed through a series of chemical solutions that remove substances such as protein and fat and isolate the RNA. The extracted RNA contains both the patient’s genetic material and the virus RNA.
The sample goes through the four PCR cycles. If the virus is present, its DNA attaches to markers that release a fluorescent dye. If the dye exceeds a certain amount, the infection is confirmed present. This method is fast and timely, and it is highly accurate.
Review of Top 10 PCR Machines for COVID-19 Detection
1. ABI QuantStudio 3D Digital PCR System ($9,999.00)
ABI Applied Biosystems QuantStudio 3D Digital PCR System is equipped with design and analysis software that facilitates fast and easy use. It can analyze highly sensitive data and can be used for broad applications such as gene expression, regulation, and variation. You do not need to buy any licenses to use it, and once connected to the Quant Studio system, you can access all your data. It comes in two formats; 96-well 0.2ml and 96-well 0.1ml.
- Easy to use
- Comes in two formats
- Can handle a wide range of applications
- Suitable for sensitive data
- Comes with a laptop
- Systems cannot be upgraded
2. Quant Studio 5 ($8,999.00)
It uses the same principals as the Quant Studio 3 and is also suitable for highly sensitive analysis data. It performs well under high-pressure conditions. Its software can be manipulated to suit your needs. It does not need any licenses to operate. It also comes in two-volume formats of 96-well 0.2ml and 96-well 0.1ml.
- Easy to use
- Comes in two capacities
- Can handle many applications
- It is more user-interactive
- Locked flow and pause features
- Does not come with a laptop
3. Applied Biosystems 7500 ($8,999.00)
ABI Applied Biosystems 7500 offers high performance, multicolor real-time diagnosis. It also has high resolution melting analysis and gives results in under half an hour. It comes in one capacity of 96-well format. It also has a system upgrade kit.
- It is fast
- It is easy to use
- Built for high performance in sensitive analysis
- Multicolour real-time diagnosis
- High-resolution melt
- Comes in one capacity format
- No laptop computer
4. Rotor-Gene from Qiagen ($9,500.00)
With a wide optical range, this PCR boasts the ability to conduct different applications with ease. Its software has taken into account dyes that could be used in the future, and its system allows you to create new detection wavelength combinations. It also has a unique centrifugal rotary design that allows the tube to tube variation, uniform detection, fast ramping, and negligible equilibrium and guarantee for your results.
- It has an extensive optical range
- Comes with a wide range of applications
- Sturdy design that ensures minimal maintenance and longevity
- Unique rotary design
- The software can be altered to suit your needs.
- It is a bit slower than other PCRs
5. QIAstat-Dx from Qiagen ($25,497.00)
This particular brand was designed for the diagnosis of the SARS-CoV-2 virus. It provides simultaneous qualitative detection and identification of respiratory pathogens of viral and bacterial nature with a single panel test. It detects over 22 pathogens and is fast and highly accurate. This machine can also detect co-infections, giving valuable insight into the quality of samples. It is easy to use since it uses a combination of wet and dry reagents.
- It is extremely fast
- It can detect up to 22 different pathogens
- Easy for technicians to use
- Highly automated
- Highly accurate
- It detects co-infections
- This device is more expensive than most PCR machines.
6. Bio-Rad T100 Thermal Cycler
This machine is small in stature with an intuitive touch screen that facilitates easy programming. It comes in two sample capacities and an average ramp rate of 2.5 degrees Celsius per second. It weighs 20lb (9kg). It also comes in several formats and allows for fast PCR optimization using a unique thermal gradient. Protocols can also be organized using customizable folders. This small machine will give you consistent results.
- It is small and saves up on space in the lab
- The intuitive touch screen makes it convenient to operate
- It allows you to organize protocols using customizable folders
- Can handle a lot of work and give consistent results
- It is slower than other thermal cyclers
7. Bio-Rad CFX96 ($10,755.00)
This PCR machine is a powerful tool that is built to give precision and flexibility in its detection system. It is a 6-channel real-time PCR that combines precise temperature control and advanced optical technology. You can configure its software to fit your specifications and can run without a computer. It has an average ramp rate of 33 degrees Celsius per second, and a temperature range of 0-100 degrees Celsius. It also has a high optical detection with six filtered diodes.
- Easy to set up and run
- Minimal sample and reagent use
- Fast data analysis
- High-performance software
- Has configurable software
- It is quite heavy (21kg / 47lb)
8. Roche LightCycler 480 ($8,999.00)
The Roche LightCycler 480 boasts a wide range of probe formats. It is highly sensitive, fast, and results obtained can be reproduced. It supports both mono and multicolor applications and multiplex protocols. You can customize the benchtop instrument to meet your requirements. It can also operate as a robotically controlled high through-put solution.
- It is sturdy and has high-performance hardware
- The software is innovative and highly efficient
- Its disposables are highly designed
- Reagents are application-optimized for various experiments
- It does not have an interactive display screen
9. Veriti Thermal Cycler ($1,599.00)
This thermocycler has multiple temperature zones that facilitate high accuracy in determining annealing temperature, which results in accurate findings. 6 Pieler blocks give you six different temperature zones. It will also save you time since you can run six different procedures with six separate annealing temperatures. The thermal cycler can also be used for sample incubation with six precise temperatures.
- It has multiple temperature zones
- It is highly accurate
- It saves you time since you can do six different procedures at the same time
- The thermal cycler can be used as an incubator
- It has a display interface
- Access from your computer or laptop
- It is a bit pricey as compared to other machines.
10. Agilent AriaMx ($9,999.00)
The Agilent AriaMx combines a novel thermocycler and an advanced LED optical system. It is suitable for amplification, detection, and data analysis. It has comprehensive data analysis software. It has a closed-tube PCR format and is appropriate to use with many fluorescence detection chemistries. It also has an intuitive interface touchscreen that makes it easy to use.
- Comprehensive data analysis software
- Intuitive touchscreen for convenient use
- Usable with many fluorescence detection chemistries
- Online reviews have indicated software unreliability and malfunction.
The field of medicine has come a long way, not just in knowledge of diseases and their treatment, but also in the analysis necessary to make a diagnosis. There is a need to come up with fast and accurate testing methods that help in the quick identification of pathogens. The analysis of these disease-causing microorganisms gives insight into their behavior and response to various conditions, and this goes a long way in coming up with ways to treat the infections they cause.
COVID-19 is a disease caused by the SARS-CoV-2 virus. This virus strain attacks the respiratory system, and a cure for it is yet to be found. The need to mass test and obtain quick results is dire. The disease is highly contagious, and it is crucial to identify those infected so that they can be placed in quarantine to try and curb the spread.
PCR is a suitable method for testing the novel coronavirus presence in humans. The process is fast, as compared to other methods that take days and sometimes even weeks. The use of PCR gives results in hours. Also, it provides an in-depth analysis of the virus. This analysis includes information on the way it behaves and mutates. This kind of study will go a long way in understanding how to handle the virus, and to eventually come up with a vaccine.
The choice of PCR machine is determined by factors such as the population of patients that visit a hospital. Some machines are better suited to handle many samples in a given time, and some can even analyze different samples at the same time.
Frequently Asked Questions
What is the average cost of a PCR machine?
There is a broad diversity in the PCR market, and the costs vary from manufacturer to manufacturer. They mainly range from $15,000 to $90,000.
Where can I purchase a PCR machine?
Many online sites sell these machines, but it is most recommendable to buy them from Authorized Distributor.
How much will it cost to get a PCR test?
It depends on what the doctor needs to be tested, but you will spend an average of $15-$20.
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