Colorimetric sensing towards spermine based on supramolecular pillar[5]arene reduced and stabilized gold nanoparticles.

ABSTRACT

We develop a novel and fast colorimetric sensing platform for spermine (Sp) by using macrocyclic host hydroxyl pillar[5]arene (P5) molecule reduced and stabilized Au nanoparticles via the supramolecular host-guest recognition interaction between P5 and Sp. The P5-modified Au nanoparticles (P5-Au) are easily obtained by redox reaction between hydroxyl groups in P5 and Au3+ in HAuCl4, where hydroxyl groups are oxidized to carboxyl groups and Au3+ is reduced to Au0+ under alkali catalysis at room temperature without NaBH4 or other reducing agent. A uniform diameter of about 5.0 nm and wine red color P5-Au nanoparticles can be synthesized by this green and rapid method. The mechanism of redox reaction between P5 and HAuCl4 is studied by the XPS and 13C NMR, and the P5-Au is characterized by the TEM, XRD and XPS.