Single cell sensing and degradation of H2O2 via Cyt c@ZIF-8 confined nanoreactor

Oxidative stress refers to an imbalance characterized by an excess of reactive oxygen species (ROS), which is closely linked to the pathogenesis of various diseases. Nanotools enabling single-cell sensing and degradation of ROS are envisioned to offer deeper insights into oxidative stress. Herein, we design a nanoreactor based on Cyt c encapsulated within zeolitic imidazolate framework-8 (ZIF-8) nanoparticles confined in a nanopipette. Cyt c@ZIF-8 nanoparticles are fixed within a cone-tipped glass nanopipette to create a nanoconfined reaction tunnel. Upon the insertion of Cyt c@ZIF-8 nanoreactor into a single living cell, the subcellular H 2 O 2 is sorted into the nanopipette and degraded by Cyt c@ZIF-8, causing an obvious change in ionic current signal. The ZIF-8 triggered enhancement of Cyt c enzyme activity enables effective H 2 O 2 elimination. Molecular dynamics simulations confirmed that the stability and activity of Cyt c could be significantly enhanced upon encapsulation in ZIF-8. The designed nanotool achieves the double effects of H 2 O 2 sensing and oxidative stress scavenging at single cell level, demonstrating significant potential for future research related to Cyt c. • We developed a Cyt c@ZIF-8 nanoreactor for H 2 O 2 sensing at single-cell level. • Cyt c in ZIF-8 enhances activity, confirmed by molecular simulations. • The nanoreactor shows potential for monitoring cascade reactions in single cells.