Hypothesis
Media routinely used to simulate the same body environment are interchangeable for testing how a collagen scaffold degrades.
What failed
The three media produced major differences in the mechanical properties and mass loss of identical collagen scaffolds, while micro-CT, X-ray diffraction and infrared spectroscopy showed only minor structural differences, so the measured degradation depended largely on which "equivalent" medium was chosen.
Broken assumption
Any standard simulated body fluid stands in for the same in vivo environment.
Why
The authors point out that no general recommendation exists for selecting a simulated body environment, and argue results must not be simplified from a single medium.
From the published paper: Suchý et al. Materials, 2021. ↗CC BY