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

We develop a novel and fast colorimetric sensing platform for spermine (Sp) by using macrocyclic host hydroxyl pillarl5larene (P5) molecule reduced and stabilized Au nanopartides via the supramolecular host-guest recognition interaction between P5 and Sp. The P5-modified Au nanopartides (P5-Au) are easily obtained by redox reaction between hydroxyl groups in PS 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 nanopartides can be synthesized by this green and rapid method. The mechanism of redox reaction between P5 and HAuCl4 is studied by the XPS and C-13 NMIL and the P5-Au is characterized by the TEM, XRD and XPS. (C) 2019 Published by Elsevier B.V.