Mechanical characterization of soft silicone gels via spherical nanoindentation for applications in mechanobiology

Abstract

As a biocompatible material, soft silicone gels like CY52-276 have been applied to many engineering fields associated with interactions between mammalian cells and extracellular matrices/substrates, due to its nontoxicity, ease of preparation, optical transparency and tunable mechanical properties. Precise quantification of mechanical properties of silicone gels is crucial for quantitatively investigating mechanical responses of cells to microenvironments. Addressing the material with high surface energy, we design a new strategy for the nanoindentation technique to reduce or even eliminate the effect of interfacial adhesions with the aid of some specified buffers. Next, we dissect the dependence of its Young’s modulus on the ratios of monomers and crosslinkers and curing conditions, and therefore identify a dose–response relationship between its moduli and the corresponding prepolymer compositions. With the non-linear large deformation nanoindentation tests, we further showed that the two-parameter Mooney–Rivlin model may well characterize the hyperelastic deformations of the materials with different composition ratios. These pave the way for more precise exploration of the interaction between cells and extracellular matrix and the underlying mechanotransduction pathways in mechanobiology. Precise quantification of mechanical properties of silicone gels is crucial for quantitatively investigating mechanical responses of cells to microenvironments. Addressing the material with high surface energy, we design a new strategy for the nanoindentation technique to reduce or even eliminate the effect of interfacial adhesions with the aid of some specified buffers. Next, we dissect the dependence of its Young’s modulus on the ratios of monomers and crosslinkers and curing conditions. These pave the way for more precise exploration of the interaction between cells and extracellular matrix and the underlying mechanotransduction pathways in mechanobiology.