A sustainable luminescence-enhanced tri-assembly of polyoxometalate-peptide-polyamine developed for ultrasensitive spermine determination and discrimination.

ABSTRACT

A supramolecular strategy with sustainable emission amplification of an environmentally sensitive polyoxometalate, Na9[EuW10O36]·32H2O (EuW10), has been constructed for the Spm determination and discrimination. The EuW10 has no response to Put and other biogenic amine but a sensitive response to Spm (LOD = 0.56 nM) and Spd (LOD = 85.93 nM), respectively. Assembling with a cationic peptide from HPV E6, GL-22, achieved the EuW10/GL-22 assembly, which showed a unique enhanced emission response to Spm and distinguished it from Spd successfully. Furthermore, a synergistic rather than competitive binding of Spm to the EuW10/GL-22 assembly was revealed using FT-IR, and NMR titration spectra, together with DLS and TEM, essentially for the three-component sensing system. Besides, both EuW10 and EuW10/GL-22 assembly were successfully applied to the Spm determination in human urine and serum, suggesting the potential of these sensing approaches in detecting trace amounts of Spm in the clinic. Therefore, the constructed supramolecular assembly can detect the Spm sensitively (LOD = 2.0 nM) and efficiently distinguish it step-wise from other biogenic amines. It is a facile, straightforward, sensitive, and selective strategy for Spm determination and discrimination, which will be helpful in addressing the related biological and clinical requirements.