In her recently published paper in Analyst, Yifei Xu, a graduate student in our group, described the differentiation of carboxylate anions on disposable paper supports such as common printer paper, filter paper, chromatography paper. Differentiation is achieved with sensors built from commercially available components using non-covalent interactions, namely a cationic PAMAM dendrimer and a small organic fluorophore (calcein). The assay's physical dimensions were chosen to fit the microwell plate standard so detection could be carried out on widely available plate reader instrumentation. Small, yet nuanced changes in fluorescence associated with carboxylate binding to the PAMAM dendrimer could be used to discriminate each carboxylate. The long-term stability ("shelf life") of the assembled sensing system on paper support was also excellent.
The paper was featured on the cover of Analyst!