Cell culture

Cell culture is the scientific process of growing cells under controlled conditions outside of their natural environment.

This technique allows researchers to study living things in a highly predictable way. By isolating cells from a donor, scientists can observe how they behave without the complexity of a whole body. This field is essential for modern biology and medicine. It provides models to test new drugs and understand how diseases spread. Whether working with animals, plants, or microbes, cell culture is a fundamental tool for discovery.

To keep cells alive, scientists must replicate the environment found inside a living organism. Most animal cells are kept in an incubator at a steady temperature of 37 °C. This mimics the warmth of a body. The cells live in a liquid called a growth medium. This medium acts as a life-support system by providing essential nutrients. It includes carbon sources like glucose for energy and amino acids to build proteins. It also contains vitamins, minerals, and gases such as oxygen and carbon dioxide. To monitor the health of this environment, scientists use a pH indicator called phenol red. This dye turns yellow if the environment becomes too acidic and purple if it becomes too basic.

Cells are categorized by how they physically exist in their culture environment. Some cells are grown as a suspension culture. These cells float freely within the liquid medium, much like blood cells move through a body. Other cells are considered adherent cells. These cells require a solid surface to attach to so they can grow. Most cells from solid tissues are adherent and will form a monolayer, which is a single layer of cells.

Scientists can also use 3D culture techniques. This involves growing cells on fibrous scaffolds or within gels. These three-dimensional structures are more similar to how tissues look in a living body.

There are different ways to obtain the cells used in these experiments. Primary cells are those taken directly from a living subject. These cells are highly realistic but usually have a limited lifespan. They eventually undergo senescence, which means they stop dividing. In contrast, scientists can use immortalized cell lines. These are populations of cells that have been modified to divide indefinitely. This can happen through random mutation or by adding specific genes, such as the telomerase gene.

These stable lines allow for long-term, consistent research.

The history of cell culture is built on many important discoveries. In the 19th century, Sydney Ringer developed salt solutions that helped keep an isolated animal heart beating. In 1885, Wilhelm Roux established basic principles by maintaining embryonic chicken tissue in a warm saline solution. Later, Ross Granville Harrison demonstrated that frog embryonic cells could grow in clotted lymph.

These early steps paved the way for the massive advancements seen in the 20th century. The term "tissue culture" was eventually coined by the American pathologist Montrose Thomas Burrows.

One of the most significant impacts of cell culture was in the field of virology. During the 1940s and 1950s, growing viruses in cell cultures became a vital method for making vaccines. John Franklin Enders, Thomas Huckle Weller, and Frederick Chapman Robbins won a Nobel Prize for their work. They discovered how to grow viruses in monkey kidney cell cultures. This breakthrough allowed for the mass production of the polio vaccine developed by Jonas Salk. This shows how controlling a tiny environment can lead to global health improvements.

Cell culture also extends to the world of plants through plant tissue culture. Gottlieb Haberlandt was a pioneer in this area. In 1902, he proposed the idea of totipotentiality. This is the concept that any single plant cell has the potential to grow into a complete, whole plant. Today, scientists use these methods to grow entire plants from just small pieces of tissue. This connects cell biology to agriculture and environmental science, proving that the same principles of growth apply across many different types of life.