Photophobic and phototropic movement of a self-oscillating gel.

A photosensitive self-oscillating gel that incorporates the Belousov-Zhabotinsky reaction can undergo rhythmic mechanical oscillations. We exploit the dependence of the oscillation frequency on light intensity to generate both photophobic and phototropic movement of the gel under differential illumination. Our findings may be used in designing intelligent sensors that can execute biomimetic behaviours.