Thermal transport across membranes and the Kapitza length from photothermal microscopy

An analytical model is presented for light scattering associated with heat transport near a cell membrane that divides a complex system into two topologically distinct half-spaces. Our analysis is motivated by experiments on vibrational photothermal microscopy which have not only demonstrated remarkably high contrast and resolution, but also are capable of providing label-free local information of heat transport in complex morphologies. In the first Born approximation, the derived Green's function leads to the reconstruction of a full 3D image with photothermal contrast obtained using both amplitude and phase detection of periodic excitations. We show that important fundamental parameters including the Kapitza length and Kapitza resistance can be derived from experiments. Our goal is to spur additional experimental studies with high-frequency modulation and heterodyne detection in order to make contact with recent theoretical molecular dynamics calculations of thermal transport properties in membrane systems.

Automated summary

An analytical model is proposed for studying light scattering related to heat transport around a cell membrane. The model divides a complex system into two distinct half-spaces and is motivated by experiments on vibrational photothermal microscopy. The model can reconstruct a full 3D image with photothermal contrast and derive important parameters from experiments, such as Kapitza length and Kapitza resistance. The aim is to encourage further experimental studies to explore thermal transport properties in membrane systems using high-frequency modulation and heterodyne detection.