Thermoelectric fields hold nanoparticles Thermoelectric fields hold nanoparticles, Published online: 29 March 2018; doi:10.1038/s41566-018-0143-2Optical trapping of metal nanoparticles with conventional ‘tweezers’ can be challenging due to absorption and heating. Now, an opto-thermoelectric trapping approach that exploits heating has been demonstrated.