Aptamer-based spectrofluorometry for cellular prion protein using N,N′-bis[3,3′-(dimethylamino)propylamine]-3,4,9,10-perylenetetracarboxylic diimide.

A new spectrofluorometric method for cellular prion protein (PrPC) was developed based on the regulation of N,N′-bis[3,3′-(dimethylamino)propylamine]-3,4,9,10-perylenetetracarboxylic diimide (DAPER) fluorescence. As a perylene derivative, DAPER emits strong fluorescence in the form of free monomer in aqueous medium, but not in the form of aggregates. In this contribution, we found that the aptamer of PrPC could induce the aggregation of DAPER, and the bright fluorescence of DAPER was completely quenched. The quenched fluorescence, however, was recovered if PrPC was further added, which was ascribed to the specific binding of PrPC to its aptamer and the releasing of free DAPER monomers. This signalling mechanism makes it possible to detect PrPC by fluorescence spectroscopy. The assay allows the selective determination of PrPC in aqueous solution with high sensitivity and exhibits a good linear range from 0.4 to 1.6 nmol L−1. Moreover, this probe can be applied to monitor the level of PrPC in human urine samples with satisfactory results. [ABSTRACT FROM AUTHOR]