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Publication - Professor Anthony Davis

    Rapid Macrocycle Threading by a Fluorescent Dye-Polymer Conjugate in Water with Nanomolar Affinity

    Citation

    Peck, EM, Liu, W, Spence, GT, Shaw, SK, Davis, AP, Destecroix, H & Smith, BD, 2015, ‘Rapid Macrocycle Threading by a Fluorescent Dye-Polymer Conjugate in Water with Nanomolar Affinity’. Journal of the American Chemical Society, vol 137., pp. 8668-8671

    Abstract

    A macrocyclic tetralactam host is threaded by a highly fluorescent squaraine dye that is flanked by two polyethylene glycol (PEG) chains with nanomolar dissociation constants in water. Furthermore, the rates of bimolecular association are very fast with k<inf>on</inf> ≤ 10<sup>6</sup>-10<sup>7</sup> M<sup>-1</sup> s<sup>-1</sup>. The association is effective under cell culture conditions and produces large changes in dye optical properties including turn-on near-infrared fluorescence that can be imaged using cell microscopy. Association constants in water are ∼1000 times higher than those in organic solvents and strongly enthalpically favored at 27 °C. The threading rate is hardly affected by the length of the PEG chains that flank the squaraine dye. For example, macrocycle threading by a dye conjugate with two appended PEG2000 chains is only three times slower than threading by a conjugate with triethylene glycol chains that are 20 times shorter. The results are a promising advance toward synthetic mimics of streptavidin/biotin.

    Full details in the University publications repository