Retrievable hydrogel networks with confined microalgae for exceptional antibiotic degradation and stress tolerance

Antibiotic contamination has emerged as a global challenge, which increases antibiotic resistance and threats human health and ecosystems. Bioremediation using microorganism offers sustainable methods to degrade such pharmaceutical contaminants. However, these microorganisms exhibit reduced activity under high-stress conditions, and are difficult to recycle and potentially leak into environment as microbial pollutions. Here, we report bioprinted retrievable microalgae hydrogel networks (MHNs) for efficient antibiotic wastewater treatment by confining the living microalgae in 3D double-network hydrogels, which achieves enhanced antibiotic degradation , self-regeneration properties, and recyclable ability. Particularly, coating MHN with tannic acid (MHN@TA) generates a semipermeable membrane to prevent the leakage of microalgae from the network (<1.3% for 7 days), ensuring the containment of potential microbial biohazards. The biohybrid system protects the biological activity of microalgae, enabling the superior microalgal proliferation and antibiotic degradation up to 400 mg/L. Free-standing MHN@TA fencing systemsare also manufactured to demonstrate their practical applications. This study provides insights of microalgae-material interactions in bioremediation and offers a valuable blueprint for designing robust biohybrid systems.