The Bank Of Swimming Organisms at the Micron Scale (BOSO-Micro)

TL;DR

This paper compiles and analyzes experimental data on the motility of unicellular microswimmers, organizing biological and physical parameters across different species to serve as a comprehensive reference for future research.

Contribution

It provides the first systematic biophysical survey of motile behavior in diverse unicellular organisms, integrating empirical data with fluid mechanics models.

Findings

Organized data on swimming speeds, sizes, and flagella properties.

Applied low Reynolds number fluid mechanics models to interpret motility.

Highlighted variability within and across organism groups.

Abstract

Unicellular microscopic organisms living in aqueous environments outnumber all other creatures on Earth. A large proportion of them are able to self-propel in fluids with a vast diversity of swimming gaits and motility patterns. In this paper we present a biophysical survey of the available experimental data produced to date on the characteristics of motile behaviour in unicellular microswimmers. We assemble from the available literature empirical data on the motility of four broad categories of organisms: bacteria (and archaea), flagellated eukaryotes, spermatozoa and ciliates. Whenever possible, we gather the following biological, morphological, kinematic and dynamical parameters: species, geometry and size of the organisms, swimming speeds, actuation frequencies, actuation amplitudes, number of flagella and properties of the surrounding fluid. We then organise the data using the established fluid mechanics principles for propulsion at low Reynolds number. Specifically, we use theoretical biophysical models for the locomotion of cells within the same taxonomic groups of organisms as a means of rationalising the raw material we have assembled, while demonstrating the variability for organisms of different species within the same group. The material gathered in our work is an attempt to summarise the available experimental data in the field, providing a convenient and practical reference point for future studies.