Multivalent (Nitrilotriacetic Acid)‐End‐Functionalized Polystyrenes by ATRP and Their Self‐Assembly

The synthesis of tri-(nitrilotriacetic acid) (NTA)-end-functionalized polystyrenes using an initiator containing tert-butyl protected NTA moieties, by atom transfer radical polymerization (ATRP) of styrene is described. First, a suitable ATRP initiator is prepared andsubsequently characterized by H-1 and(13)C NMR spectroscopy, gel-permeation chromatography(GPC), and matrix-assisted laser desorptionionization time-of-flight (MALDI-TOF) mass spectroscopy.The structures of the tri-NTA-end-functionalized polystyrenes (tri-NTA-PS) areconfirmed by H-1 and C-13 NMR spectroscopy. Tri-NTA-PS itself produces self-assembled spherical aggregates with approximate to 40-60 nm diameters in water/THF, whereas nickel-complexed tri-NTA-PS produces spherical core-shell hybrid aggregates with approximate to 90-115 nm diameters with His-tagged GFP in water/DMF (DMF 4 vol%), as confirmed by transmission electron microscopy and dynamic light scattering measurements.