Figure 1.

Measurement of tumor swelling. (A) δ_ref is defined as the thickness attained when NaCl concentrations are isotonic enough to shield electrostatic interactions; δ > δ_ref tumor swelling in hypotonic solutions (the thickness of the sample increases); the stress required to compress the sample from thickness δ to δ_ref defines the swelling stress, T_c. (B) The tumor specimen was initially compressed to 10% strain and allowed to relax. Subsequently, NaCl solution of specified concentration was added, causing the swelling of the tissue, which reached a new equilibrium. Finally, the specimen was compressed for another 20% strain. The difference in the stress between the two equilibriums was quantified as the swelling stress. Islet shows a schematic of the experimental set up.