摘要： Cesium-lead-halide perovskite quantum dots (PQDs), are a highly promising class of next-generation optical material for bio-imaging applications. Herein, we present a nanocomposite strategy for the design of water soluble, highly luminescence CsPbBr3 PQD nanocomposites without modifying the crystal symmetry and photoluminescence (PL) property. Water soluble PQDs are reproducibly synthesized via encapsulating CsPbBr3 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 protection layer to effectively prevent degradation of PQDs in water. Outer shell PEG layer also helps to develop biocompatible PQDs. Reported data indicate that encapsulating CsPbBr3 PQDs with polymer helps to improve the photoluminescence quantum yield (PLQY) from 83% to 88%, which may be due to decrease in the surface defects after the effective polymer coating. Experimental data show that PL intensity from CsPbBr3 PQD nanocomposites remain unchanged even after 30 days of exposure in air. Similarly, reported data indicate that nanocomposites retain their luminescence properties in water for first 8 days and then decreases 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 few hours. Exosomes are highly promising avenue for accessing tumor type and stage and to monitor cancer treatment response. Reported data reveal that anti-CD63 antibody attached PQD nanocomposites are capable of tracking of triple negative MDA-MB-231 breast tumor derived exosomes via binding using anti- CD63 antibody and selective green luminescence imaging using PQD nanocomposites.