Estimation of the mass density of biological matter from refractive index measurements

Möckel C, Beck T, Kaliman S, Abuhattum S, Kim K, Kolb J, Wehner D, Zaburdaev V, Guck J (2024)

Publication Type: Journal article

Publication year: 2024

Journal

Pages Range: 100156

Article Number: 100156

DOI: 10.1016/j.bpr.2024.100156

Abstract

The quantification of physical properties of biological matter gives rise to novel ways of understanding functional mechanisms. One of the basic biophysical properties is the mass density (MD). It impacts the dynamics in sub-cellular compartments and plays a major role in defining the opto-acoustical properties of cells and tissues. As such, the MD can be connected to the refractive index (RI) via the well known Lorentz–Lorenz relation, which takes into account the polarizability of matter. However, computing the MD based on RI measurements poses a challenge, as it requires detailed knowledge of the biochemical composition of the sample. Here we propose a methodology on how to account for assumptions about the biochemical composition of the sample and respective RI measurements. To this aim, we employ the Biot mixing rule of RIs alongside the assumption of volume additivity to find an approximate relation of MD and RI. We use Monte–Carlo simulations and Gaussian propagation of uncertainty to obtain approximate analytical solutions for the respective uncertainties of MD and RI. We validate this approach by applying it to a set of well-characterized complex mixtures given by bovine milk and intralipid emulsion and employ it to estimate the MD of living zebrafish (Danio rerio) larvae trunk tissue. Our results illustrate the importance of implementing this methodology not only for MD estimations but for many other related biophysical problems, such as mechanical measurements using Brillouin microscopy and transient optical coherence elastography.

Authors with CRIS profile

Additional Organisation(s)

Involved external institutions

Max-Planck-Institut für die Physik des Lichts (MPL) / Max Planck Institute for the Science of Light Germany (DE) Max-Planck-Zentrum für Physik und Medizin (MPZPM) Germany (DE)

How to cite

APA:

Möckel, C., Beck, T., Kaliman, S., Abuhattum, S., Kim, K., Kolb, J.,... Guck, J. (2024). Estimation of the mass density of biological matter from refractive index measurements. Biophysical Reports, 100156. https://doi.org/10.1016/j.bpr.2024.100156

MLA:

Möckel, Conrad, et al. "Estimation of the mass density of biological matter from refractive index measurements." Biophysical Reports (2024): 100156.

BibTeX: Download