Efficient Trapping and Degradation of Polyethylene Terephthalate Nanoplastics Using Enzyme‐Functionalized Bowl‐Shaped Janus Particles

Polyethylene terephthalate (PET) nanoplastics are pervasive aquatic contaminants due to their high dispersibility and persistence, yet their removal at extremely low concentrations remains challenging. Here, we report a “capture‐and‐degrade” strategy for PET nanoparticle degradation using enzyme‐functionalized bowl‐shaped Janus particles. Amphiphilic Janus particles featuring a hydrophobic concave surface were synthesized via interfacial emulsion polymerization. A thermostable PET hydrolase, HotPETase, fused with the hydrophobic anchor peptide LCI, was specifically immobilized on the concave region. This architecture efficiently captures PET nanoparticles from dilute systems, promoting enzyme–substrate colocalization and thereby enhancing their degradation. The strong interaction between the Janus particles and the HotPETase‐LCI fusion protein provides the immobilized enzyme with high operational activity and stability, enabling reuse for more than 17 cycles with over 90% of its initial activity retained. Furthermore, integration into a packed‐bed continuous‐flow reactor achieved 96% PET removal during 20 h of operation, corresponding to a space‐time conversion of 1.5 × 10 14 particles L −1 ·h −1 . This work establishes a scalable platform based on topology‐engineered Janus materials for PET nanoplastic remediation and may inspire new approaches for the capture and degradation of other nanoplastics from dilute conditions.