A new ratiometric fluorescence detection of heparin based on the combination of the aggregation-induced fluorescence quenching and enhancement phenomena

A new ratiometric fluorescence detection of heparin is reported with the ensemble of 1 and 2. This method is based on the respective ACQ (aggregation-caused quenched emission) and AIE (aggregation-induced emission) features of anthracene and tetraphenylethene. DLS, CLSM and fluorescent spectral investigations suggest that the variation of the fluorescence intensity ratio I(497)/I(421) is due to the formation of aggregates of 1 and 2 with heparin. Moreover, this ratiometric fluorescence method can be used to distinguish heparin from its analogues (HA, Dex). In order to demonstrate the practical utilization of this ratiometric fluorescence method, the fluorescence spectra of the ensemble of 1 and 2 were measured in the presence of serum, and the results indicate that it is possible to eliminate the interferences from other biomolecules by either subtracting the background fluorescence intensities or lowering the pH values of the sample solutions.