By specially tuning a laser beam, the scientists found that they could grip and manipulate a number of different kinds of microscopic objects immersed in water, including bacteria. Polymers are large spaghetti-like molecules that are constructed from large numbers of identical, smaller molecules strung together like beads on a string.
Polymers figure in everything from plastics to synthetic fabrics to the DNA in living cells.
Previously, scientists had been limited to studying polymers in bulk, by the millions and billions. Chu's laboratory is providing some of the first detailed studies of the behavior of individual polymers that, not surprisingly, are revealing that they don't act in exactly the way that scientists had expected. Studying the properties of polymers in bulk is something like trying to determine the nature of animals in a zoo using only information about averages, Chu explained. If someone did a series of experiments that only measured the average size, weight and number of legs of the animals, he would get a distorted picture. For example, he might find that the average number of legs on the animals is 2.7, and then look for a theory of animal development that could explain his finding.