Before revision:  This work presents the first demonstration of magnetic microscale rocker robot (microrocker bot) capable of bidirectional movement on flat as well as biological surfaces, when actuated by a single compact electromagnet .
After revision:  This work presents a novel control mechanism and contact design that enables bidirectional steering via biasing the neutral position of the microrobot. Equipped with rockers to contact the substrate, the microrobot, hence microrocker bot, is capable of well-controlled forward and backward movement on flat as well as biological surfaces, when actuated by a single compact electromagnet .