Determination of the Liposomal Bulk Modulus by Molecular Acoustics

Abstract

In the context of nanomechanics, elasticity is a notable physical property that has garnered recent interest for its roles at the nano-bio interface. This work introduces a novel application of molecular acoustics (ultrasound velocimetry and densitometry) to assess volumetric elasticity modulusor bulk modulus as a tool to characterize liposomal elasticity. One of the main advantages of the presented technique is that the liposomes remain unaltered throughout the entire measurement process, that is, without the artifacts by adsorption onto a substrate and the effect of a probe. Another strength highlighted in our proposal is that the obtained elasticity modulus does not depend on a physical model, such as the Hertz model for atomic force microscopy, and the required considerations, such as assuming the sample is homogeneous and isotropic. We consider that the bulk modulus obtained through ultrasonic velocimetry provides a genuine measure of the liposomal elasticity of the system under study.