Sequestration nanonics are modified neural nanonics. They are used by organised crime to control members of their gang / cartel / racket / coven.
The nanonics in question have been programmed so that if the user disobeys an order, then the unfortunate individual can have their memories erased, personalities changed or worse, their brains shorted out. Great if you don't want any grasses exposing your illegal manufacturing!
Some sequestration nanonics used by organised crime prevent the 'user' from discussing certain subjects with people outside the organisation. The mere wish to mention any criminal activity to the police, for example the location of an antimatter production facility — will cause the 'users' brain to short out, killing him.