Cell culture: in vitro model system and a promising path to in vivo applications.

In the 1800s, scientists discovered a useful alternative to in vivo research, the in vitro cell culture system. Cell culture has been widely used in academia and industry for diverse issues such as cell biology research to vaccine production and cancer drug discoveries. This article will provide a brief introduction and summary of cell culture history with some key milestones and discuss the future of cell culture from the author’s perspective. When talking about cells, what comes to mind? For me, it is the most well-known cell line, HeLa. HeLa cells were the first immortalized human cell line and may be one of the most important scientific discoveries of the last century. In 1951, HeLa cells were isolated and propagated from cervical cancer tissue from a patient named Henrietta Lacks (HeLa) by Johns Hopkins researcher, Dr George Gey. Since then, this cell line has played an important role in many scientific discoveries, from outer space research to the COVID-19 vaccines, and of course, cancer research all over the world. Other important cell lines include the hybridomas established in 1975 (hybrid cell lines that produce antibodies), mouse embryonic stem cells (ESCs) established in 1981, and human ESCs in 1998. Most recently, in 2006, the world was amazed by the exciting discovery of induced pluripotent stem cells (iPSCs) which were reprogrammed from adult cells back to ESC-like states as a promising alternative to ESCs. In both basic and translational research, cell culture is an indispensable tool. It is becoming more important with the rapid development of reprogramming, gene editing, and in vitro differentiation as well as threedimensional (3D) culture and bioprinting technologies.