Direct Monitoring of Cell Membrane Vesiculation with 2D AuNP@MnO2 Nanosheet Supraparticles at the Single-Particle Level.

We herein demonstrate robust two-dimensional (2D) UFO-shaped plasmonic supraparticles made of gold nanoparticles (AuNPs) and MnO2 nanosheets (denoted as AMNS-SPs) for directly monitoring cell membrane vesiculation at the single-particle level. Because the decorated MnO2 nanosheets are ultrathin (4.2 nm) and have large diameters (230 nm), they are flexible enough for deformation and folding for parceling of the AuNPs during the endocytosis process. Correspondingly, the surrounding refractive index of the AuNPs increases dramatically, which results in a distinct red-shift of the localized surface plasmon resonance (LSPR). Such LSPR modulation provides a convenient and accurate means for directly monitoring the dynamic interactions between 2D nanomaterials and cell membranes. Furthermore, for the endocytosed AMNS-SPs, the subsequent LSPR blue-shift induced by etching effects of reducing molecules is promising for exploring the local environment redox states at the single-cell level.