A centrifuge is one of the most common pieces of equipment in a biological lab. The instrument makes use of centrifugal force to separate components in a fluid, causing denser particles to settle to the bottom of a centrifuge tube. After centrifugation, particles are separated into layers based on their densities.
One of the most useful applications of centrifuges in biotech is for health diagnostics. A common example is for health check-ups using a panel of blood biomarkers. Centrifuges are a crucial part of sample processing because there are many elements within a blood sample that need to be separated as much as possible to provide an accurate diagnosis. After centrifugation, blood is separated into three layers. The bottom layer contains red blood cells. The percentage of red blood cells and the amount of oxygen they carry can be used to diagnose conditions like anemia, where there are insufficient red blood cells to carry oxygen. The middle layer is white blood cells, and its number can provide information about the body’s ability to fight infection. The top layer is plasma, which contains common biomarkers such as urea and creatine, which indicate kidney health.
Applications for ultracentrifuges
Extracellular vesicles are membrane-bound vesicles between 30-10,000 nm in size secreted from cells that play a role in cellular communications. They are produced in small quantities, but can be isolated from bodily fluids like blood, urine, and saliva via ultracentrifuges to provide information on health. For instance, cancer cells secrete more extracellular vesicles than their healthy counterparts and their vesicles have been found to contain oncoproteins and RNA species that contribute to cancer progression, including metastasis. By analyzing the contents of extracellular vesicles, researchers are trying to develop biomarkers for the diagnosis and surveillance of cancer.
Ultracentrifuges play a pivotal role in isolating pure extracellular vesicles as they can spin at much higher velocity than conventional centrifuges to separate particles with similar densities. In blood plasma, there are many types of biomolecules and cellular secretions of similar densities and to isolate the analyte of choice, these components must be separated very finely to obtain a pure sample. This is also why ultracentrifugation to isolate extracellular vesicles may take hours and multiple steps of washing and purification.
Extracellular vesicles are also being developed by biotech companies for drug delivery applications, owing to their bioactive properties and tropism toward targeted tissues. In this case, another reason why ultracentrifuges are important pieces of equipment to isolate extracellular vesicles from manufactured cells is due to their scalability. For therapeutic purposes, a large number of extracellular vesicles must be isolated quickly, but cells only produce limited quantities. An ultracentrifuge that can work with multiple samples at a time with high isolation throughput is ideal for biotech manufacturing.
Newer centrifuges are equipped with programmable acceleration and deceleration, which has been shown to help terminate unwanted side reactions and reduce waiting time. This feature can also minimize mechanical damage to extracellular vesicles during ultracentrifugation.
Refrigeration is an important feature of centrifuges to minimize sample denaturation, especially with biomolecules like proteins. Pre-cooling of centrifuge rotors and having minimal rise in temperature when rotors are spinning at maximum speed are also useful to prevent heat-induced sample damage.
As more research institutions are going green, manufacturers are designing centrifuges that are more environmentally friendly by ensuring lower energy consumption and using recyclable materials.