Cell culture refers to the removal of cells from an animal or plant and their subsequent growth in a favorable artificial environment. That is why cell culture is always an in vitro procedure. The cells may be removed from the tissue directly or disaggregated enzymatically or mechanically. They may also be derived from a cell line that has already been established.
Cell culture has a wide variety of applications, including cancer research, drug development, vaccine production, and a whole lot more. For that reason, it is an essential topic for students of biology and medicine.
Students learning cell culture for the first time might find the lessons daunting. But there are many ways to make it more engaging and approachable. Read on to find out how.
First of all, let’s take a look at why students find it challenging to learn cell culture. Here are the top three reasons experienced by both students and teachers.
Growing animal cells in culture takes days. Because it takes time for the cells to divide to appreciable levels, they are hard to see at first. Even under a microscope, early-stage cell cultures have only very few cells that can be seen.
Cell culture involves many meticulous processes in the lab. These include techniques like:
Working in a cell culture hood
Nutrient medium preparation
Students need to know the basics of these techniques before they can fully understand cell culture. The amount of material to cover may intimidate them and eventually discourage them from studying the topic further.
Cell cultures need nutrient media, buffers, serum, and many other reagents to function properly. When one or more key components are missed, cells will not proliferate.
Reagent preparation tends to be the most tedious part of cell culture, so students first need to have a good grasp of the different reagents and why they are needed. They also need to master reagent preparation so they can do it quickly and correctly in the lab.
Based on the difficulties students have when studying cell culture, here are five tips for educators to make the topic more interesting. Each piece of advice addresses a particular challenge that students face.
If teaching cell culture can be made more approachable for students, they will gain mastery more quickly. They will also recall key concepts more easily when they take higher biology, molecular biology, or medicine courses.
Cell culture provides an easy and highly cost-effective tool for researchers in many different fields. It is one of the major tools used in cellular and molecular biology. It provides excellent model systems for studying the normal physiology and biochemistry of cells, the effects of drugs and toxic compounds in cells, mutagenesis, and carcinogenesis. It is also used in drug screening and development, as well as large-scale manufacturing of biological compounds like vaccines. The major advantage of using cell culture is the consistency and reproducibility of results that can be obtained from using a batch of clonal cells.
Cell culture hood (Image source: Wikimedia Commons)
Pictures, diagrams, illustrations, and videos are helpful in making students better comprehend concepts regarding cell culture. Moreover, students can appreciate molecular biology lab techniques more when their learning is aided by graphics.
Videos, in particular, can make teaching practical concepts easier. Students can replay video demonstrations of cell harvesting, passaging, preservation, and other important cell culture protocols as many times as they need. This way, they can have a good grasp of these essential skills before working on a real lab bench.
Interactive simulations are even better. They let students manipulate lab instruments and reagents virtually, so it’s as if they’re doing the real thing. If they make mistakes, no real objects will break, it will not cost anything, and they are at no risk of injury. Once they master the technique in the virtual world, they will be more confident as they perform actual experiments in the real lab. The image below is from Labster’s simulation entitled Cell Culture Basics: Plate, split and freeze human cells.
Before students can properly learn cell culture, they need to have mastered the basics. It is a good idea to ensure that students have thoroughly learned these fundamental concepts.
Primary culture refers to the stage after the cells are harvested from animal tissue and proliferate under the appropriate conditions. The cells will divide until they form a monolayer on the culture vessel.
Confluence is when cultured cells form a single layer covering the entire exposed surface of the culture vessel. If nothing is done after this point, the cells will stop dividing.
When cultured cells reach confluence, they must be subcultured (or passaged). The cells are transferred to a new vessel with fresh growth medium to provide more room for continued growth. These cells have a limited life span, so passaging must be done regularly to keep the cells thriving.
After a certain number of passages, the primary culture becomes a cell line. The cells at this point have uniform genotypes and phenotypes.
Cell lines derived from primary cultures have a limited life span. As they are passaged, cells with the highest growth capacity predominate. Eventually, all of the cells will have identical characteristics, leading to a cell line.
Cell lines can also be immortalized. They will have acquired the ability to proliferate indefinitely, either through genetic mutations or artificial modifications. Examples include HeLa, 3T3, and HEK293 cell lines.
A stem cell can either replicate itself or differentiate into other cell types. Stem cells are unspecialized, meaning they do not have any tissue-specific structures that allow them to perform distinct functions. Stem cells are useful when researchers want to produce specific kinds of cells that are hard to obtain.
Keeping and using sterile containers, media and reagents is crucial for successful cell culture, as this helps to maintain the cells free from contamination. Airborne particles that carry microorganisms, dirty incubators, and work surfaces are all sources of biological contamination by microorganisms such as bacteria, fungi, and viruses.
For this reason, employing the aseptic technique provides a barrier between the sterile cells that we wish to culture and the environmental microorganisms that may contaminate them. It consists of a set of procedures that reduce the probability of contamination from these sources. There are four key elements to the aseptic technique: keeping the work areas sterile, good personal hygiene, sterile reagents and media, and sterile handling.
Cell culture environment
Culture conditions vary widely for each cell type. But the artificial environment in which the cells are cultured invariably consists of a suitable vessel containing the following:
A proper culture medium where cells can grow and survive. That includes:
A substrate or medium that supplies the essential nutrients (amino acids, carbohydrates, vitamins, minerals)
Gases (O2, CO2), usually provided by an incubator
Regulated physicochemical conditions (pH, osmotic pressure, temperature), provided by both culture media and incubator
Most cells are anchorage-dependent and must be cultured while attached to a solid substrate (adherent cultures). For these cells, adhesion is crucial for survival, growth, division, and differentiation. Therefore, the surfaces of cell culture vessels must be chemically modified to provide that substrate. There are also other cells that can be grown floating in the culture medium (suspension cultures).
Adherent cultures should be passaged when they are in the log phase before they reach confluence. Otherwise, it takes them longer to recover when reseeded. Normally, confluence can be detected visually by estimating how much free space there is between cells. Usually, the normal range to perform the cell passage is 70-90% confluence.
It is also important to passage cells according to a programmed schedule. This ensures a reproducible behavior of the cells, making it easier to monitor their health. Deviations from the growth patterns usually indicate that the culture is unhealthy or a component of the culture system is not functioning properly. Therefore, it is strongly recommended to keep a detailed record of each cell culture.
Virtual lab simulations are excellent tools for teaching cell culture. Labster is determined to deliver fully interactive advanced laboratory simulations that make use of gamification elements like storytelling and scoring systems while exposing students to an immersive, realistic, 3D environment.
Check out this simulation of Cell Culture Basics: Plate, split and freeze human cells at Labster. This virtual lab allows students to experience how cell culture is performed. After learning all about it, students can be more confident when the time comes to do it on their own in a real lab! The image below is an example of what students can explore in the simulation.
Please take a look at the following image from the Labster’s Virtual Lab called Cell Culture Basics: Plate, split and freeze human cells or get in touch to find out how you can start using virtual labs with your students.
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