Intracellular Dynamic Assembly of Deep‐Red Emitting Supramolecular Nanostructures Based on the Pt…Pt Metallophilic Interaction

Abstract

Many drug delivery systems end up in the lysosome because they are built from covalent or kinetically inert supramolecular bonds. To reach other organelles, nanoparticles hence need to either be made from a kinetically labile interaction that allows re‐assembly of the nanoparticles inside the cell following endocytic uptake, or, be taken up by a mechanism that short‐circuits the classical endocytosis pathway. In this work, the intracellular fate of nanorods that self‐assemble via the Pt…Pt interaction of cyclometalated platinum(II) compounds, is studied. These deep‐red emissive nanostructures (638 nm excitation, ≈700 nm emission) are stabilized by proteins in cell medium. Once in contact with cancer cells, they cross the cell membrane via dynamin‐ and clathrin‐dependent endocytosis. However, time‐dependent confocal colocalization and cellular electron microscopy demonstrate that they directly move to mitochondria without passing by the lysosomes. Altogether, this study suggests that Pt…Pt interaction is strong enough to generate emissive, aggregated nanoparticles inside cells, but labile enough to allow these nanostructures to reach the mitochondria without being trapped in the lysosomes. These findings open new venues to the development of bioimaging nanoplatforms based on the Pt…Pt interaction.

Highly Efficient Deep-Blue Phosphorescent OLEDs Based on a Trimethylsilyl-Substituted Tetradentate Pt(II) Complex

“…However, Pt­(II) complexes in the concentrated solution or the solid state tend to stack together due to their square planar geometry and Pt–Pt metallophilic interactions through their overlapping empty d z 2 orbitals. As a result, they show not only native emission but also additional excimer or aggregate emission in the long-wavelength region. − While this feature is good for inducing red or near-IR (NIR) emissions, it is a problem for realizing deep-blue OLEDs. , Therefore, hindering the solid-state molecular stacking and intermolecular interactions of these complexes are required to achieve a high-quality blue emission.…”

Supramolecular Assembly of Organoplatinum(II) Complexes for Subcellular Distribution and Cell Viability Monitoring with Differentiated Imaging

“…All these results indicate that complex 1 is gradually enriched in the nucleus to form the aggregates, independent of the health conditions of the cells. Cellular uptake of complex 1 at different culture concentrations of 10 μM and 50 μM exhibits a similar time dependence, and the short incubation time (0.5 h) suggests that the monomeric state of complex 1 can readily permeate through the plasma membrane and accumulate intracellularly under passive diffusion control [15b] . The accumulation of red emission in the nucleus is realized by migration of complex 1 to the nucleus driven by electrostatic interaction due to the negative charge of the nucleus, which was found to induce further assembly upon increasing the local concentration of the monomers.…”

Near-infrared metal agents assisting precision medicine: from strategic design to bioimaging and therapeutic applications

“…In 2021, Bonnet et al further investigated the PtÁ Á ÁPt interactions at a cellular level. 122 The authors synthesized two isomeric Pt(II) complexes using the tetradentate ligands HMeL1 and HMeL2. Complex 18 was further away from the bridging NMe group.…”