Although prepared slides reveal many details about biological specimens, they always leave at least one question dangling: How does this look when it’s alive? A biologist wonders how the organism or molecular component behaves in a dynamic, natural context, and how it interacts with its environment, making up the very foundation of live-cell imaging. In its most basic form, live-cell imaging allows biologists to examine and analyze living samples. This capability completely changes what can be learned about life, and how that information can be used—from basic research through biotechnology and medicine.
One of the key requirements of this field is having live and healthy specimens, which can be imaged statically, like taking a snapshot of a living biological sample. Live-cell imaging can also involve time-lapse methods, which provide a biologist with dynamic information by periodically taking images over time, showing, for example, how a protein moves in a membrane over time.
In fact, cellular dynamics provides a keen area of interest. Applying live-cell imaging on a cellular level exposes biomolecular processes in action. That information—such as observing one protein interact with another—reveals functional information. To get the right information, though, the specimen must remain alive and as unperturbed as possible. The sample’s environment must encourage the most natural—and unaltered—conditions that can be maintained. Some advanced tools, including incubators, help biologists preserve a sample’s natural conditions with the simultaneous ability to image ongoing processes. In addition, a biologist requires tools that label and help to track specific elements, like proteins, in a sample. The development of a broad range of fluorescent proteins completely transformed the ability to label very specific structures and track their location. Moreover, existing options makes these tools easy to use, even when tracking multiple targets.
To get started in live-cell imaging, a biologist uses several tools: reagents to keep the cells alive, dyes or other markers to label specific molecules or structures, an incubator to provide the right environment, plus a microscope and a digital imaging system. Many cells and tissue never experience light, so the tools used for live-cell imaging must be as gentle as possible—reducing phototoxicity to the sample. That means using a microscope that makes the best of the available light, and a detection system that creates images from the least light possible. The advances in basic digital cameras push the possibilities far beyond what was conceivable even a few years ago.
This Essential Knowledge Briefing introduces readers to the general field of live-cell imaging. It explains the fundamental challenges and solutions, as well as describing some of the applications of live-cell imaging through case studies, and it forecasts the key advances ahead.