Fluorescent Polymer Synthesis and Functionalization

All of the chemicals and solvents were purchased from Sigma-Aldrich (St. Louis, MO, USA) and TCI America company (Portland, OR, USA) unless indicated otherwise. Poly(9,9-dioctylfluorene) (PFO) (average MW 147 000, polydispersity 3.0) was purchased from ADS Dyes, Inc. (Quebec, Canada). BODIPY 520 dye, BODIPY 680 dye, and BODIPY 520-fluorene copolymer were synthesized according to our previously published protocols.^{1 (link)} Polystyrene grafted ethylene oxide functionalized with carboxyl groups (PS-PEGCOOH, main chain MW 8500, graft chain MW 1200, total chain MW 21 700, polydispersity 1.25) was purchased from Polymer Source Inc. (Quebec, Canada). Streptavidin was purchased from Invitrogen (Eugene, OR, USA). Quantum Dot 525 was purchased from Life Technologies Corporation of Thermo Fisher Scientific (Carlsbad, CA, USA). All chemicals were used as received without further purification. High purity Milli-Q water (18.2 MΩ·cm) was used throughout the experiments.