Almost everyone has heard of the famous example where an opera singer shatters glass with the mere sound of their voice. This is due to a phenomenon called resonant frequency. A team of researchers wondered if they could reproduce the same effect with living cells, as they exhibit similar properties to liquid crystals. They wondered if by sending a specific electric signal (using devices with plasma antennas that pulse on and off), they could affect the cells, see their reactions and thus search for the exact frequency that would directly shatter a living microorganism, just like crystal glass would.
Fun stuff with resonance: https://youtu.be/vNuDxc9tZMk