Self-propelled AzBA-algae microrobots enable rapid and stable dynamic remediation of sulfamethoxazole in aqueous...

Sulfamethoxazole (SMX), a common sulfonamide antibiotic, is a widespread aquatic contaminant. Conventional water treatment suffers from low removal efficiency and toxic byproducts, whereas synthetic microrobots are restricted by short lifespan, toxic propellants and poor environmental adaptability. Herein, we develop biohybrid AzBA-algae microrobots for dynamic SMX remediation. The microrobots are fabricated by surface modification of Chlamydomonas reinhardtii with DBCO-PEG₄-NHS, followed by conjugation with p-azidobenzoic acid (AzBA) via strain-promoted azide-alkyne cycloaddition. DFT calculations confirm high-affinity binding between AzBA and SMX via hydrogen bonding and π-π stacking. Owning to intrinsic self-mobility, the microrobots greatly improve SMX recognition and enrichment. They maintain a stable mobility of ∼11.3 μm·s^-1 in eight water matrices and keep activity for 24 h even at 0.5 mg·L^-1 SMX. The microrobots achieve 83.5% SMX removal in ultrapure water within 2 h, 5.7 times higher than raw algae (14.7%), and attain 84.1-87.7% removal in six natural water samples. This low-cost, eco-friendly biohybrid platform enables efficient SMX remediation and provides a scalable strategy for eliminating various aquatic pollutants.