Atomic force microscopy may enable quick differentiation of metabolic profiles in bacteria

Bacteria can move on the nanoscale, and this nanomotion may provide insights on the metabolic activity of those bacteria and the effects of any drugs used against them. Traditional clinical methods, however, take a very long time to execute. Pleskova et al. developed a new method to characterize bacterial nanomotion using atomic force microscopy (AFM).

AFM usually uses a cantilever to characterize a 3D map of a surface, but here the cantilever was used in another way: the bacterial cells were attached to the cantilever. The authors found that different bacterial strains produce very specific oscillation profiles in an AFM image, enabling quick differentiation between different types of bacteria. These nanomotion profiles could change depending on the nutrient medium the bacteria were fed.

“AFM allowed us to assess oscillations produced by bacteria and find differences arising from various conditions and strains which was possible due to high sensitivity of the sensor,” author Svetlana Pleskova said. “Soft cantilevers reacted differently on bacterial strain’s nanomotions, and any additional influences such a change of medium provoked changes in the signal.”

To obtain their results, the authors first attached bacterial microorganisms to the AFM cantilever, verifying their presence using scanning electron microscopy. Then, they used mathematical analysis and a short-time Fourier transform to process the resulting AFM oscillation signals, analyzing them to find patterns and similarities between different experiments.

Pleskova says the team’s method can be especially useful for medical laboratories and clinics since it is much quicker. However, since AFM can incur a large cost, the team will continue researching cheaper and simpler systems using the same principle.

Source: “Nanomotion of bacteria to determine metabolic profile,” by S.N. Pleskova, E.V. Lazarenko, N.A. Bezrukov, R.N. Kriukov, A.V. Boryakov, M.E.Dokukin, and S.I. Surodin, Nanotechnology and Precision Engineering (2023). The article can be accessed at https://doi.org/10.1063/10.0022171 .