Thermosensitive, reversible luminescence properties and bright fluorescence imaging of water-soluble quantum dots/microgels nanocompounds

At room temperature, the self-assembly of CdTe/ZnS quantum dots (QDs)/poly(N-isopropylmethacylamide-co- methylacrylic acid) [QDs/P(NIPAM–MAA)] hybrid microgels were achieved. The temperature-dependent swelling and shrinking behavior of polymer microgels played an important role in the photoluminescence (PL) changes of hybrid microgels. At 25 °C, polyethylenimine modified-QDs and P(NIPAM–MAA) microgels (at the swelling state) were combined by electrostatic attraction to form nanocompounds. At 45 °C, nanocompounds' shrinking triggered strong scattering centers, together with marked PL decrease. Almost whole reversible PL changes were observed between 25 °C and 45 °C after repeated heating-cooling cycles. In addition, the nanocompounds exhibited well monodisperse spheres and bright PL imaging, the average diameter was found to be approximately 300 nm.

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► Water-soluble quantum dots encapsulated into thermosensitive microgels exhibited reversible luminescence behavior between 25 °C and 45 °C.
► TEM testified the acquirement of quantum dots/microgels nanocompounds.
► Luminescent mechanism was discussed.
► These nanocompounds were applied in fluorescence imaging.