A Graphene Oxide-based AIE Probe For Heparin Detection

Heparin is known as a polysaccharide which has a lot of negative charges.Because of the extensive biological function of heparin,it plays an important role in the field of medicine.At present,the common methods for heparin detection are time-consuming,complicated and have poor reproducibilities.In recent years,sensors based on fluorescent materials have become more and more popular because of their simpleness and sensitivities.After the phenomenon of aggregation induced emission（AIE）had reported,the AIE luminogens have been used as new fluorescent materials for the detection of heparin.However,this method suffers from strong background noise and may influence the results of experiments.Because of the unique physical,chemical and optical properties,graphene has been widely used in many fields.In recent years,graphene oxide（GO）has been used as a platform for fluorescent detection.This paper mainly focus on the design and synthesis of a new AIE material.It was used for the detection of heparin using GO as a platform.The main results obtained are listed as below:（1）In this paper,we synthesized three of 1,2-Diphenylethene compounds through the improved Wittig reaction,which have hydroxyl group,halogen group and amino cation,respectivily.They were measured by NMR spectrum and UV-vis spectroscopy after the purification by column chromatography,recrystallization and preparative reversed-phase high performance liquid chromatography.In the ¹H NMR and ¹³C NMR spectra,the peak splitting and the integral area can be correlated well with the number and position of H and C of the compounds.The results show that the products are purified.（2）The results of experiments show that the three compounds can emit purple fluorescence in the aggregation state,and their fluorescence characteristics can be determined by PL spectrum.After the detection,it is sure that they have AIE properties.（3）It is found that 1,2-Diphenylethene compound with amino cation shows a purple fluorescence in the states of aggregation.Therefore,it was used as a fluorescent probe for the heparin detection.The experimental results show that the exist of GO can cause the fluorescence quenching,when the oxygen-rich functional groups enable GO to interact with the fluorophore with positive charge through electrostatic interactions.When heparin sodium was added,because of the more negative charges,the fluorophore was escaped from GO,and with a result of fluorescence enhancement.This new material is efficient for the heparin detection.