Fig. 5a–c.

Measuring biomechanical properties at increasing length scales. a In general, the elastic moduli of the constituent ECM molecules are higher than elastic moduli of the connective tissues themselves (Akhtar et al. 2009). In order, therefore, to understand the mechanical role played by age-related changes in molecular abundance, distribution and structure it is necessary to characterise the mechanical properties of tissues at the nano-scopic, micro-scopic and macro-scopic lengths scales. b, c Scanning acoustic microscopy (SAM) image of an unfixed cryo-sectioned ferret aorta (b) and a fluorescence microscopy image of the same section post-stained with haematoxylin and eosin (c). Variations in wavespeed in the SAM image (which are correlated with material stiffness) closely match the distribution of elastic fibres imaged in the fluorescence microscope. Scale bar 100 μm