One-step synthesis of gold colloids using amidoaminocalix[4]resorcinarenes as reducing and stabilizing agents. Investigation of naproxen binding

Abstract

© 2017 Elsevier B.V.Amido(dimethylamino) calix[4]resorcinarenes with different substituents on the lower rim (-CH3 (С1), −C5H11 (C5), −C11H23 (C11)) both as reducing and stabilizing agent in an aqueous solution were used for the fabrication of stable gold colloids. Gold colloids are characterized by spectrophotometry, FTIR − spectroscopy, transmission electron microscopy, dynamic light scattering. It is found that increase of the macrocycle's concentration towards HAuCl4 concentration during the synthesis leads to the decrease in the size of formed particles. It is shown that the size of gold nanoparticles (AuNPs) decreases with the increase of the hydrophobicity of the substituents on the macrocycles lower rim (C1@Au − 4–14 nm, C5@Au - 10–11 nm, C11@Au − 7–8 nm). The monolayer packing of the macrocycle molecules on the surface of the metal particle for C1@Au and bilayer − for C5@Au and C11@Au, providing both the stabilization of AuNPs and their solubility in water, are proposed. Temperature and pH variation during the synthesis showed that the optimal synthesis conditions for all kinds of particles C1@Au, C5@Au, C11@Au are spontaneous installed during the synthesis pH (for C1@Au − pH 8.10, C5@Au − pH 8.56, C11@Au − pH 8.63) and the synthesis temperature of the 25 °C. High binding fraction of drug substrate naproxen on the surface of AuNPs modified by C5 and C11 macrocyclic aggregates due to the ordering of the macrocycles on the particle surface and enhancing their receptor ability towards naproxen is defined by fluorescence method.