The pyranine-benzalkonium ion pair: A promising fluorescent system for the ratiometric detection of wound pH

Pyranine is a non-toxic fluorescent dye, with a broad range of applications in biomedicine where it allows precise ratiometric detection of pH within the physiological pH window. Hereby, the facile synthesis, potentially interesting for commercial applications, of a novel ion pair between pyranine and benzalkonium is described. Benzalkonium, a quaternary ammonium salt with potent antimicrobial properties, makes pyranine sufficiently hydrophobic to allow its incorporation in conventional membranes and commercial wound dressings while maintaining its pH sensing performance unaffected and conferring the resulting ion pair strong antimicrobial properties. In conclusion, this novel fluorescent ion pair could be extremely promising for the non-invasive monitoring of wound pH.