vitro

In vitro, a Latin phrase meaning “in glass,” describes experiments and processes conducted outside a living organism, typically in a laboratory vessel such as a petri dish or culture flask. The term is commonly used in contrast with in vivo, meaning inside a living body. While “vitro” is sometimes encountered as shorthand in popular language, proper scientific usage favors “in vitro.”

In vitro methods are widespread across biology and medicine. They include cell culture and molecular biology assays that allow researchers to study cellular processes, gene expression, and biochemical reactions under controlled conditions. In vitro systems are used for diagnostic tests, drug screening and toxicology assessments, and basic research into disease mechanisms. In agriculture, plant tissue culture and micropropagation rely on in vitro conditions to maintain and propagate plant material. A well-known clinical application is in vitro fertilization, where oocytes are fertilized outside the body and embryos are transferred to the uterus.

The main advantages of in vitro approaches are experimental control, reproducibility, and the ability to isolate specific variables. However, they have limitations: cells and tissues in culture may not fully replicate the complexity of whole organisms, and results may not always translate to in vivo contexts. Ethical and regulatory considerations often accompany in vitro research, especially when human cells, embryos, or reproductive technologies are involved.

Overall, in vitro techniques remain foundational to modern biology and medicine, enabling experimentation, diagnostics, and therapeutic development in a controlled, outside-the-body setting.