Water-Soluble and Bright Luminescent Cesium-Lead-Bromide Perovskite Quantum Dot-Polymer Composites for Tumor-Derived Exosome Imaging.

Cesium-lead-halide perovskite quantum dots (PQDs) are a highly promising class of the next-generation optical material for bioimaging applications. Herein, we present a nanocomposite strategy for the design of water-soluble, highly luminescence CsPbBr 3 PQD nanocomposites without modifying the crystal symmetry and photoluminescence (PL) property. Water-soluble PQDs are reproducibly synthesized via encapsulating CsPbBr 3 PQDs with polystyrene- block -poly(ethylene- ran -butylene)- block -polystyrene (PS-PEB-PS) and poly(ethylene glycol)- block -poly(propylene glycol)- block -poly(ethylene glycol (PEG-PPG-PEG). In the reported design, the polystyrene triblock polymers strongly interact with the hydrophobic parts of PQDs, and the water-soluble PEG moiety acts as a protection layer to effectively prevent degradation of PQDs in water. The outer shell PEG layer also helps to develop biocompatible PQDs. Reported data indicate that encapsulating CsPbBr 3 PQDs with a polymer helps to improve the photoluminescence quantum yield (PLQY) from 83% to 88%, which may be due to a decrease in the surface defects after the effective polymer coating. Experimental data show that the PL intensity from CsPbBr 3 PQD nanocomposites remains unchanged even after 30 days of exposure in air. Similarly, reported data indicate that nanocomposites retain their luminescence properties in water for the first 8 days and then decrease slowly to 60% of its initial PL intensity after one month. On the other hand, the PL emission for the PQD without polymer encapsulation is completely quenched within a few hours. Exosomes are a highly promising avenue for accessing tumor type and stage and monitoring cancer treatment response. Reported data reveal that anti-CD63 antibody-attached PQD nanocomposites are capable of tracking triple-negative MDA-MB-231 breast tumor-derived exosomes via binding using anti-CD63 antibody and selective green luminescence imaging using PQD nanocomposites.