What are the experimental observation methods of cell culture in vitro?

The experimental observation methods of cultured cells in vitro are as follows:

In order to observe the structure of cells, it is necessary to improve the contrast of the structure by other means.

The cells were observed by dark field microscope. The dark field microscope uses a special condenser to present bright images on a dark background.

Observed by time-shift microscope, time-shift microscope can directly record the continuous dynamic changes of cells.

In vitro living cell staining observation and so on.