Researchers at Israel’s Bar-Ilan University and the IDC in Herzliya have used brainwaves of humans under strain, to control the release of medicine by tiny robots made from shells made of DNA.  The technique could be used (for example) to treat schizophrenia or depression.

http://www.dailymail.co.uk/sciencetech/article-3759832/Mind-controlled-nanobots-release-drugs-inside-BRAIN-Tiny-machines-help-treat-depression-epilepsy.html