It is clearly visible, that the Young's modulus of the dry polymer network around the AuNPs is around ten times higher than that for the swollen network immersed in water forming a hydrogel (0 to 25 GPa for air and 0 to 2 GPa for water). The values for both Young's moduli in air and in water were derived from the histograms of the hydrogel's Young's moduli at random positions (around 30 AuNPs). The maximum of the fitting, representing the most probable value, was then identified as 1.542 ± 0.162 GPa in air and 0.119 ± 0.008 GPa in water. In addition, the degree of swelling of the polymer network was determined by comparing the size of the hydrogel nanostructure (distance between upper and lower) in either air or water (N = 50) from AFM images in contact or QI mode (data not shown). The size of the hybrid features in air was 320.3 ± 2.6 nm while in water it was slightly larger at 349.2 ± 2.2 nm, which can be attributed to swelling.