A new diagnostic approach is emerging that identifies bacteria through their unique sound signatures, potentially paving the way for faster infection identification and antibiotic susceptibility testing.
While bacteria don’t produce audible sound, they generate minuscule mechanical vibrations at the nanoscale as they attach to surfaces and become metabolically active. Researchers have developed a method to detect these vibrations using an extremely thin graphene membrane, which functions as a nanomechanical resonator, converting the vibrations into measurable signals. This innovation could significantly reduce the time needed to diagnose infections and determine the most effective treatment.
Each bacterial species produces a unique frequency pattern, akin to an acoustic fingerprint and these patterns aren’t random. By analyzing these signals in the time-frequency domain, researchers can create datasets suitable for classification algorithms.
Nanodrum
At the heart of the system is a highly sensitive sensor based on a graphene membrane that operates as a “nanodrum.” When a bacterium lands on the membrane, it induces tiny mechanical movements. Graphene’s low mass and high sensitivity allow even individual bacteria to be detected.
This approach aligns with broader developments in micro- and nanosensor technology, where mechanical resonances are used to directly measure biological processes without the demand for optical labels or extensive culturing steps.
Machine learning connects sound to species and resistance
The key breakthrough lies in interpreting the signals. Researchers from TU Delft, SoundCell, and Reinier de Graaf Hospital trained machine-learning models on large amounts of vibration data. The system can distinguish between bacterial species based on their unique “sound.”
changes in the vibration pattern also provide information about antibiotic susceptibility. This allows for the combination of identification and resistance determination in a single measurement step.
Diagnostics in hours instead of days
Traditional microbiological diagnostics require culturing bacteria, followed by separate tests for antibiotic sensitivity, a process that often takes several days.
With the new method, this can be reduced to just a few hours – and in some cases, approximately one hour – because measurements are taken at the level of individual bacteria, eliminating the need for culturing. The findings could lead to more rapid and targeted treatment of bacterial infections, improving patient outcomes and reducing the spread of antibiotic resistance.
