Nanoscale viscoelastic properties and adhesion of polydimethylsiloxane for tissue engineering

It has shown that altering crosslink density of biopolymers will regulate the morphology of Mesenchymal Stem Cells (MSCs) and the subsequent MSCs differentiation. These observations have been found in a wide range of biopolymers. However, a recent work published in Nature Materials has revealed that MSCs morphology and differentiation was unaffected by crosslink density of polydimethylsiloxane (PDMS), which remains elusive. To understand such unusual behaviour, we use nanoindentation tests and modelling to characterize viscoelastic properties and surface adhesion of PDMS with different base:crosslink ratio varied from 50:1 (50D) to 10:1 (10D). It has shown that lower crosslink density leads to lower elastic moduli. Despite lower nanoindentation elastic moduli, PDMS with lowest crosslink density has higher local surface adhesion which would affect cell-biomaterials interactions. This work suggests that surface adhesion is likely another important physical cue to regulate cell-biomaterials interactions. [graphic not available: see fulltext]