Green Algae-Based Microrobots for the Active In Vivo Delivery

Green algae-based microrobots display diverse advantageous features concerting consistent self-propulsion and their functionalization capabilities. The long-lasting swimming behavior of natural microalgae offers excellent motion behavior, which provides remarkable potential as the carrier for gastrointestinal (GI) tract delivery. When orally administered in vivo into mice, our green algae-based microrobots substantially improved GI distribution of the payload compared with traditional magnesium-based micromotors, which are limited by short propulsion lifetimes. Such appealing motion behavior and extended lifetime of green algae-based microrobots allow precise GI localization and enhanced cargo deliveries in GI tissue for practical biomedical applications. Taking one specific example, green algae-based microrobots can be equipped with macrophage membrane-coated nanoparticles to efficiently capture pro-inflammatory cytokines ‘on-the-fly’. The dynamic green algae-based microrobots outperform static counterparts by enhancing cytokine removal through continuous movement, better distribution, and extended retention in the colon to ease inflammatory bowel disease free from side effects. The advantages are not restricted to GI applications, as green algae-based microrobots also excel upon treating the mouse model of acute pseudomonas aeruginosa pneumonia, where the algae microrobots effectively reduce bacterial burden and substantially lessen animal mortality, with negligible toxicity. Overall, these findings highlight the attractive functions of green algae-based microrobots for the active in vivo delivery.