Seductive higher dimensions could consign glass dishes to history.
When the otherwise obscure Julius Richard Petri, one-time assistant to pioneering bacteriologist Robert Koch, published in 1887 his methodology for growing colonies of bacteria on a base of gelatin in flat glass dishes, he seemingly guaranteed his own immortality. The development of bacteriology and microbiology — not to mention molecular biology — would have been unthinkable without the modest Petri dish, which remains a fundamental laboratory item today.
But biologists starting to explore the merits of culturing cells in three dimensions (3-D), rather than in the flat-dish's two dimensions, have been stunned by the difference that it makes to the way the cells behave, which is much closer to their behaviour in vivo (see page 870). Cancer biologists find that cells can be made to switch between malignant and non-malignant states in 3-D but not in 2-D. Developmental biologists find that their cells proliferate much faster in 3-D than in 2-D. The fat lady is not yet singing for the Petri dish, but she is certainly clearing her throat.
Culturing cells in 3-D is neither convenient nor cheap, however, and won't necessarily help to answer simple biochemical questions. But it is only a matter of time before 3-D techniques become standardized and cost–benefit ratios become irresistible in many areas of biology. Those who have experienced the merits of 3-D first-hand are convinced that any biologist studying a system where the microstructure environment is important in vivo — such as neurobiology, atherosclerosis or diabetes — will have to bid the Petri dish farewell in the next decade if they are to continue being taken seriously.
Awareness of the potential of 3-D tissue culture among scientists is far too low. But the benefits of the technique are so self-evident that little marketing will be needed to persuade the uninitiated to move up a dimension, just as soon as the issues of convenience are resolved.
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