Original Covalent Approach for Gold Nanorods Immobilization onto Acid-Terminated-Cysteamine Self-Assembled Monolayers for FT-SPR Biosensor Applications

In this paper, we report an original method to immobilize gold nanorods onto mixed self-assembled monolayers (SAMs) of Mercaptoundecanoic Acid (MUA), Mercaptohexanol (MOH) and cysteamine (CYS) onto planar gold surface. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images revealed a remarkable shape and size narrow distribution on well functionalized gold surfaces, as well as a tendency to form linear assemblies after immobilization. The results highlight the good distribution of gold nanorods with an average length of 32.6 ± 0.9 nm and width of 13 ± 1.8 nm, the simplicity of the immobilization procedure of gold nanorods and the interest of using them as labels to enhance the sensitivity of FT-SPR-based sensors. gold nanostructured surface FT-SPR measurements of biorecognition using gold nanorods immobilized onto gold surfaces were performed at various prostatic antigen specific (PSA) concentrations, from 5 mg/L to 0.5 mg/L reaching a system sensitivity of 37 ± 2 cm-1/ mgL-1.