Scientists of TIPC show that rod-like tobacco mosaic virus (TMV) can self-assemble into 3D bundled structures in aqueous solution using azobenzene modified Pluronics F127 block copolymers (Azo-F127) to induce depletion. The structures are characterized by both transmission electron microscopy and dynamic light scattering. The self-assembly process can be controlled reversibly by temperature. The formation of Azo-F127 hard spheres during the self-assembly is the main cause of this phenomenon.