A team of researchers at Columbia Engineering and Lawrence Berkeley National Lab have developed a new type of force sensor that can measure piconewton to micronewton forces with high sensitivity and spatial resolution. The nanoscale sensors, called “all-optical nanosensors,” use luminescent nanocrystals that emit light when pushed or pulled. This allows for remote read-outs and eliminates the need for wires or connections. The sensors have an unprecedented dynamic range, spanning four orders of magnitude in force, and are 100 times more sensitive than existing nanoparticles.
The team used the photon-avalanching effect, where a single photon absorbed by a nanocrystal triggers the emission of many photons, to create the sensors. They also designed new nanosensors that change their luminescence color or intensity in response to applied forces. The sensors can operate in previously inaccessible environments, such as subsurface or interfacial sites, and have potential applications in robotics, cellular biophysics, medicine, and space travel. The researchers believe the new sensors will revolutionize the field of sensing, enabling the study of forces in a wide range of systems, from the subcellular to the whole-system level.