Eachcell is linked to this matrix by proteins in its membranecalledintegrins, and the cell's internalproteinskeletonis constantlytugging on theseintegrins to create ataut, tunedwhole.
What Dr Zussman and his colleagues have managed to do is break the internal bonds in the protein molecules by mixing them with a chemical called beta-mercaptoethanol.
The molecules of this protein are more or less globular, and are held in that shape by internal cross-links between different parts of the amino-acid chain of which the protein is composed.
They are, in effect, internal viruses unable to leave a cell because they lack the protein coats that allow real viruses to survive in the outside world and attach themselves to new host cells, but contributing nothing to the welfare of the cells they inhabit.