Embodiments of a system including a remotely controlled reaction device and associated controller are described. Methods of use and control of the device are also disclosed. According to various embodiments, a reaction device is placed in an environment in order to perform a chemical reaction in an environment. Exemplary environments include a body of an organism, a body of water, or an enclosed volume of a fluid. In selected embodiments, a magnetic field, an electric field, or electromagnetic control signal may be used.