Pattern-Based Sensing of Sulfated Glycosaminoglycans with a Dynamic Mixture of Iron Complexes

A dynamic mixture of iron complexes was used as a colorimetric sensor for sulfated glycosaminoglycans. The sensing ensemble was prepared by mixing [FeCl2(H2O)4] with dipicolylamine, the functionalized bipyridyl ligand N-(6-aminohexyl)-4'-methyl-2,2'-bipyridine-4-carboxamide, and the dye Evans Blue. Upon addition of the analytes, characteristic changes in the UV-Vis spectrum of the solutions were observed. The spectral changes allowed indentifying different sulfated glucosaminoglycans (unfractionated heparin sulfate, low molecular weight heparin, dextran sulfate, chondroitin sulfate A, dermatan sulfate, heparan sulfate) with the help of a linear discriminant analysis. Furthermore, it was possible to distinguish mixtures of unfractionated heparin sulfate and heparan sulfate with good resolution.