A cationic aggregation-induced emission luminogen for colorimetric and fluorimetric detection of heparin with a dual-read approach, stability and applicability in a 10% serum matrix

Abstract Accurate detection of heparin (Hep) is essential to ensure the safety of Hep medication in clinical treatment. Although a large number of Hep optical probes have been reported in the past decade, it is still an arduous task to design a Hep optical probe with satisfactory overall performance, such as dual-mode response, stability and applicability in high-concentration serum substrates. Herein, a double-charged cationic aggregation-induced emission (AIE) luminogen, PYNN, was rationally designed and readily synthesized for efficient colorimetric and fluorimetric detection of Hep. PYNN exhibits typical AIE characteristics and good water solubility, thus emitting faint fluorescence in aqueous media. In the presence of negatively charged Hep, PYNN molecules are immobilized on the Hep chain through electrostatic and van der Waals interactions to produce a PYNN-Hep complex, causing remarkable changes in the absorption and fluorescence spectra of PYNN. The spectral response of PYNN to Hep is highly sensitive, selective, rapid, reversible and stable to ambient temperature and storage time. The absorbance ratio of PYNN at 430 nm and 370 nm and its fluorescence intensity at 580 nm meet good linear relationships with Hep concentration, with a detection limit of 6.8 ng/mL, colorimetrically and fluorimetrically, 5.9 ng/mL. PYNN can serve as a highly efficient optical probe for the dual-readout approach of Hep levels in a 10% serum matrix without interference from serum components. Our work provides an efficient, convenient and practical tool for the rapid identification and precise detection of Hep, which is of great significance for its clinical detection.