Development of a fluorescent peptide for the highly sensitive and selective detection of oxytocin

Abstract

A novel oxytocin-targeting fluorescent peptide (compound 1), with a cyanopyranyl group as the fluorophore and a peptide as the binding site of oxytocin, was developed. Compound 1 allowed the detection of oxytocin by alteration of its fluorescence quantum yield. When alone in solution and unbound to oxytocin, compound 1 had a weak fluorescence emission, contrary to a much stronger fluorescence emission when associated with oxytocin. The increase in fluorescence intensity was concentration-dependent, from which a good linear relationship was observed by plotting the data as a function of oxytocin concentration. The binding and detection of compound 1 with oxytocin was not affected by the presence of foreign substances, thereby allowing for the highly selective detection of oxytocin. As an application of this fluorescent reagent, compound 1 was immobilized on the surface of magnetic beads via covalent bonding under optimal conditions. The fluorescent detection of oxytocin in rat serum was successfully achieved using magnetic beads. Overall, the experimental results of this work clearly show that compound 1 is a good probe for oxytocin detection, and can be widely employed in oxytocin detection protocols in diverse areas of research.