Article pubs.acs.org/Macromolecules
Color-Tunable Amphiphilic Segmented π‑Conjugated Polymer NanoAssemblies and Their Bioimaging in Cancer Cells Karnati Narasimha and Manickam Jayakannan* Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pune 411008, Maharashtra India S Supporting Information *
ABSTRACT: We report a unique color tunable amphiphilic segmented π-conjugated polymer design and their π-stack driven diverse self-assembled nanostructures and demonstrate their application as a new classes of aqueous luminescent nanoparticle probes for bioimaging in cervical and breast cancer cells. Oligo-phenylenevinylene (OPV) was employed as rigid luminescent π-core and oligoethyleneoxy chains were used as flexible spacers to construct new amphiphilic segmented π-conjugated polymers by Witting−Horner polymerization route. The rigidity of the π-core was varied using tricyclodecanemethyleneoxy, 2-ethylhexyloxy or methoxy pendants and appropriate π-core geometry was optimized to achieve maximum aromatic π-stacking interactions. Solvent-induced chain aggregation of the polymers exhibited a morphological transition from one-dimensional helical nanofibrous to three-dimensional spherical nanoassemblies in good/bad solvent combinations. This morphological transformation was accompanied by the fluorescence color change from blue-to-white-to-yellow. CIE color coordinates exhibited x = 0.25 and y = 0.32 for the white light followed by the collective emission from aggregated and isolated OPV chromophores. Electron and atomic microscopes, steady state photophysical studies, time-resolved fluorescent decay analysis, and dynamic light scattering method enabled us to establish the precise mechanism for the self-assembly of segmented OPV polymers. The polymers produced stable and luminescent aqueous nanoparticles of
