Tetracationic macrocycles form highly stable inclusion complexes with uric acid enabling solution-phase and paper-strip bicolor colorimetric detection of hyperuricemia

Abstract

The uric acid (UA) level in the human body is one of the important clinical indicators associated with gout and various metabolic diseases. Here, we appeal to side chain-appended tetracationic macrocycles that have intrinsic fluorescence emission to bind UA for its colorimetric detection. We show that the introduction of four aminoethoxy side chains to the naphthalene-derived macrocycle leads to a binding constant of 4.45 × 10⁶ M⁻¹, which is the highest among those achieved using reported receptors. This high binding affinity enables the generation of a visual sensing system for detecting UA of hyperuricemia from that of normal by mixing with rhodamine B, which works in solution as well as paper assays.