Navigating microalgal biohybrids through confinements with magnetic guidance

In the natural world, microorganisms constantly navigate through confined spaces—such as those found in tissues, biological gels, and soil—yet their behavior in such environments remains poorly understood. Here, we explore this phenomenon by examining the navigation of magnetic microalgal biohybrids in constrained microenvironments. By leveraging the inherent propulsion of green microalgae and external steering capabilities acquired through the magnetization of microalgal cells, our biohybrids exhibit efficient navigation in viscous and confined microenvironments. Through high-yield fabrication and magnetic manipulation, we show precise control over their movement. Our findings reveal distinct navigation patterns influenced by magnetic guidance, namely backtracking and crossing, shedding light on the unexplored dynamics of confined locomotion assisted by magnetism. Our work highlights the significance of understanding microalgal biohybrid swimming behavior, offering crucial insights for future biotechnological and biomedical applications requiring precise navigation in confined environments.