## 3 Experimental Setup  
The measurement of the four samples was performed by the pipette aspiration method with the experimental setup shown in Figure 1. In the original setup as reported in [PERSON] et al. [33], a static low pressure was used to suck the material into the pipette and the resulting deformation was measured. The elastic modulus was determined by a simple analytical approximation (1). We improved the setup by using a miniaturised loudspeaker as a replacement for the pistonphone, which was used by [PERSON] et al. and [PERSON] et al. [39; 40], in order to produce an acoustic pressure at predefined frequencies inside the pipette. The bottom end of the pipette was placed on the surface of the sample perpendicularly in the two different contact boundary conditions. Firstly, the pipette was connected to the surface with imposing various amounts of force on it. In this condition, the sample surface under the pipette wall (in an area of a ring with a pipette radius) is completely restricted in the \(z\)-direction, but it may have movement in the \(x\)-\(y\) plane. Secondly, the pipette was placed on the sample surface with a very small gap in the range of tens of micrometers. It is obvious that, in this condition, the sample surface under the pipette wall is not under any constraint and it is free to move in all the directions. We call those two setups as connected pipette and pipette with a gap. The two boundary conditions help to investigate the effect of the pipette wall's friction, force and radius on the behaviour of the surface under the fluctuating. Due to the sinusoidal sound excitation pressure within the pipette, the surface area aspires into the pipette wall and pushes in the negative \(z\)-direction as it is depicted in Figure 2b. The displacement amplitude (L) at the center of the pipette obtained from the velocity of the vibration is optically measured by  
Figure 1: Picture of the experimental setup; (**a**) with the smaller pipette, (**b**) with the bigger pipette. means of the vibrometer as a function of the excitation pressure \(\Delta P\). In this study, we assumed that the silicone samples are isotropic and homogenous and have linear elasticity:  
\[\frac{L}{a}=C\frac{\Delta P}{E}\quad\Rightarrow\quad E=C\frac{\Delta P}{\frac {L}{a}}. \tag{1}\]  
Based on those assumptions, the analytical approximation (1) taken from [PERSON] et al. [33] is used to calculate elastic modulus (E) of the samples using the pipette aspiration method. The coefficient (C) is corresponding to the effect of the pipette wall thickness (b/a), specimen thickness (h/a) and specimen radius (R/a) with respect to the pipette radius. A schematic of the pipette aspiration method and the sample deformation under the pipette are depicted in Figure 2. Since we used two different sizes of pipette, the coefficient was considered to be 1 for the smaller pipette and 1.1 for the bigger pipette, both are extracted from [PERSON] et al. [33]. By means of a transient mount, the distance between the pipette tip and the sample surface adjusted to implement the pipette with a gap boundary condition as displayed in Figure 1a. An accurate scale in tens of milli-Newton measuring range was added to the experimental setup to control the compression force of the pipette tip wall on the surface in connected pipette condition. A larger pipette with a bigger radius, 5.75 mm, was utilized in the experimental setup as shown in Figure 1b. A tiny loudspeaker (Knowles Electronics LLC, Itasca, IL, USA) is mounted in a 10 mm distance from the base of the pipette. The sound excitation pressure inside the pipette obtained by the loudspeaker was driven at ten frequency steps in the range of 50 Hz-500 Hz with 50 Hz intervals to cover the normal vocal fold oscillation frequency range. The acoustic pressure applied to the inner volume of the pipette enables having an enclosed excitation pressure on the surface of the silicone sample.