Monitoring H2 O2 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 H2 O2 at the single-cell level. LCEM-HRP could report H2 O2 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 H2 O2 . The level of transfiguration of LCEM-HRP revealed the different amounts of H2 O2 released from cells. The estimated detection sensitivity was ≈2.2×10-7  μm 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 H2 O2 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.