Mitochondrial activity detected by cantilever based sensor

Abstract

Abstract. Our team recently demonstrated that cantilever based devices can detect signature of life in a chemistry independent manner. In this technique, the organism of interest is attached onto a classical AFM cantilever. If alive, it induces nanometre scale oscillations of the cantilever that disappear once the organism is killed. The technique was successfully used on bacteria, yeast, vegetal and mammalian cells. In this work we demonstrate that the method can also be applied to sub-cellular organelles, such as mitochondria. Mitochondria are involved in cellular energy production and are present in most eukaryotic cells. Nowadays, it is believed that mitochondria were originally prokaryotes that colonized eukaryotic cells and that live in an endosymbiotic way ever since. Here we present that mitochondria are also animated by nanometre scale oscillations that depend on their metabolic state and that stop once they are inhibited. This observation opens novel avenues to investigate the numerous mitochondria-related diseases in humans.

Nanomotion detection based on atomic force microscopy cantilevers

“…Intracellular organelles such as mitochondria and chloroplasts are involved in energy generation in cells. Preliminary experiments demonstrated that active mitochondria also induce cantilever oscillations and the oscillations generated by mitochondria change upon exposure to different molecules such as malate or pyruvate ( Stupar et al, 2017a ) ( Fig. 4 ).…”

“…This type of measurement is widely used nowadays to characterize the mechanical properties ranging from single molecules to whole mammalian cells ( Krieg et al, 2018 ). For a more in depth explanation of this method, additional readings can be found in the following articles ( Kasas et al, 2015a , Stupar et al, 2017a ). Furthermore, the instrument can also assess the presence and properties of specific molecules on the scanned sample.…”

A perspective view on the nanomotion detection of living organisms and its features

“…In eukaryotes, the depolymerisation of the actin filaments dramatically reduces the oscillations amplitude indicating an important role of their cytoskeleton. Furthermore, even mitochondria 59 and conformational changes of proteins can exert a nanomotion pattern when attached to a cantilever 50 . Finally, in the case of nonmotile organisms such as cocci or mycobacteria or yeasts, more subtle mechanisms seem to play a role, such as opening and closing of ion channels or surface proteins conformational changes.…”

Living Sample Viability Measurement Methods from Traditional Assays to Nanomotion

“…An optical transduction system detects and records the dynamic oscillation frequencies of the cantilever via a laser beam reflected from the oscillating cantilever to a detector. This system’s time resolution and sensitivity are ideally suited to studying living organisms at the nanoscale [ 145 , 146 ]. The AFM oscillating cantilever method provides a simple, highly weight-sensitive possibility for direct, real-time and single- or multi-cell measurements with high accuracy.…”