This chapter has introduced many aspects of technology currently used by cell biologists. Science is driven by the technology available, and with each development we can peer more deeply into the mysteries of life.

The ability to grow cells in culture was a tremendous advance in technology—it allowed researchers to examine and explore the inner workings of cells. Techniques in cell culture are still developing; for example, they are currently contributing to the exciting developments in stem-cell research (see Chapter 21). Although most studies have used flat dishes to grow these cells, in the body they form a three-dimensional structure. Major areas of research are now examining the functions of cells in three-dimensional environments and generating three-dimensional cell organizations, such as epithelial tubes, in supported culture systems.

The discovery and use of GFP and other fluorescent proteins has revolutionized cell biology. By tagging proteins with GFP and following their localization in live cells, we have discovered that the cytoplasm of cells is far more dynamic than previously envisaged. Every year brings new technologies associated with fluorescent proteins; approaches such as FRAP, FRET, and TIRF have become widespread tools for exploring the dynamics and molecular mechanisms of proteins, either in vivo or in vitro. The potential uses of fluorescent proteins are mostly limited by one’s imagination, and new and resourceful methods are constantly being developed. We have seen a revolution in super-resolution microscopy, opening up the ability to localize molecules by light microscopy several times more accurately than was believed to be possible. Super-resolution microscopy can currently be done only on fixed samples; optimists believe it will soon be possible to achieve this level of resolution in live cells and thereby open up the possibility of watching dynamic processes at the molecular level. As these techniques develop, fewer people need to use electron microscopy, so the expertise in this important area is waning.

As we discuss in Chapter 6, RNAi and CRISPR technologies have added amazing and unanticipated new technology to the arsenal of techniques available to cell and developmental biologists. The ability to perform genome-wide screens in both the roundworm and the fruit fly has made these traditional model genetic systems even more powerful. Coupling these technologies with visual screens opens up yet another dimension. Consider the following problem: which genes in the roundworm affect the organization of a small subset of neurons? A few years ago, this would have been a technically challenging problem. Now it is possible to make a roundworm in which only those neurons are marked with GFP and then subject it to a visual genomics RNAi screen to see which gene products are necessary for the normal morphology of those neurons. More and more imaginative approaches are being developed combining RNAi with visual and functional screens, permitting an ever-deepening understanding of life processes.