Monitoring H 2 O 2 on the Surface of Single Cells with Liquid Crystal Elastomer Microspheres

Live‐imaging of signaling molecules released from living cells is a fundamental challenge in life sciences. Herein, we synthesized liquid crystal elastomer microspheres functionalized with horse‐radish peroxidase (LCEM‐HRP), which can be immobilized directly on the cell membrane to monitor real‐time release of H 2 O 2 at the single‐cell level. LCEM‐HRP could report H 2 O 2 through a concentric‐to‐radial (C‐R) transfiguration, which is due to the deprotonation of LCEM‐HRP and the break of inter or intra‐chain hydrogen bonding in LCEM‐HRP caused by HRP‐catalyzed reduction of H 2 O 2 . The level of transfiguration of LCEM‐HRP revealed the different amounts of H 2 O 2 released from cells. The estimated detection sensitivity was ≈2.2×10 −7 μ m for 10 min of detection time. The cell lines and cell–cell heterogeneity was explored from different configurations. LCEM‐HRP presents a new approach for in situ real‐time imaging of H 2 O 2 release from living cells and can be the basis for seeking more advanced chemical probes for imaging of various signaling molecules in the cellular microenvironment.