Janus microswimmers are arguably the simplest, and thus most popular system to study the dynamics of active matter. Their directed motion without external flows and ability to induce micro-mixing and thus potentially overcome diffusion limitations, holds promise for applications spanning water remediation, 57 synthetic chemistry, and smart drug delivery. For such applications, not only the enhanced recovery of microswimmers using magnetic fields, but also the ability to steer their motion by the same means is highly desirable. We therefore demonstrate an example of TNA's modularity by asymmetrically attaching mixed compositions of photocatalytic TiO 2 and magnetic Fe 2 O 3 nanoparticles in a single step (see Figure ).