Composite polymer particles with pH- and thermosensitive fluorescence consisting of a solid polymer core and a stimulus-sensitive shell doped with CdSe/ZnS QDs are presented. Organic-inorganic hybrid particles with pH-sensitive fluorescence were prepared by the layer-by-layer deposition technique. Polyacrolein particles were used as cores for deposition of hydrophilic QDs/polyelectrolyte multilayers formed by electrostatic interactions. The outermost layer was essential for application of fluorescent hybrid particles in bioassay. Hybrid particles with thermosensitive fluorescence consist of a solid poly(acrolein-co-styrene) core and a poly(N-vinylcaprolactam) (PVCL) shell doped with QDs. The temperature response of fluorescence was determined by the dependence of the QD fluorescence intensity on the distances between them in the PVCL shell, which shrinks upon heating above its lower critical solution temperature. Bioanalytical applications of developed thermosensitive particles were illustrated by examples of their use for real-time remote monitoring the local temperature of a reaction mixture in the course of exothermic chemical reactions.
This study was supported by the Ministry of Education and Science of the Russian Federation, grant no. 11.G34.31.0050, and by the European Community through the ERA-Net ICENAP project. The part of this study dealing with the photophysical properties of the QDs used for encoding of beads was supported by the Russian Science Foundation, grant no. 14-13-01160.