*4.5. Crimp Angle Measurement*

The crimp angle analyzed through TEM imaging of unloaded samples was calculated by drawing a line along the straight edges of a collagen layer and measuring the angle between the two lines using ImageJ software (NIH). Measurement lines are shown in green in Figure 5E,F for reference.

#### *4.6. Collagen and Elastin Content*

The collagen and elastin concentrations in both gular and leg tissues (*n* = 3) were determined using Biocolor Sircol ™ Insoluble Collagen and Biocolor Fastin ™ Elastin assays (Accurate Chemical, Westbury, NY). Briefly, samples ranging from 0.1 to 4.0 mg wet weight were thawed and dissociated in the fragmentation reagen<sup>t</sup> provided by the kit. We performed tissue fragmentation for 3 h at 65 ◦C under intermittent vortex mixing. Dissociated collagen was collected through centrifugation and dyed using the Sircol Dye Reagent for 30 min, followed by centrifugation. Excess liquid was drained and exposed to an acid-salt wash to remove the unbound dye and centrifuged to collect the collagen-dye pellet and remove excess dye. The alkali reagen<sup>t</sup> was added and vortexed to remove the bound dye and immediately used for colorimetric absorbance measurements. Elastin was extracted according to the protocol described briefly here. Elastin was extracted using 0.25 M oxalic acid at 100 ◦C for 2 h and precipitated using the provided precipitating agent. The solution was centrifuged to form an elastin pellet, exposed to the dye reagen<sup>t</sup> for 90 min, and vortexed intermittently. Following centrifugation, the elastin-bound dye was released using the provided dissociation reagen<sup>t</sup> and used immediately for colorimetric absorbance reading. Results from both assays were expressed in micrograms of collagen or elastin per milligram of the wet tissue sample.
