Probing the Functionalization of Gold Surfaces and Protein Adsorption by PM‐IRRAS

Abstract

The control of morphology and coating of metal surfaces is essential for a number of organic electronic devices including photovoltaic cells and sensors. In this study, we monitor the functionalization of gold surfaces with 11-mercaptoundecanoic acid (MUA, HS(CH(2) )(10) CO(2) H) and cysteamine, aiming at passivating the surfaces for application in surface plasmon resonance (SPR) biosensors. Using polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS), cyclic voltammetry, atomic force microscopy and quartz crystal microbalance, we observed a time-dependent organization process of the adsorbed MUA monolayer with alkyl chains perpendicular to the gold surface. Such optimized condition for surface passivation was obtained with a systematic search for experimental parameters leading to the lowest electrochemical signal of the functionalized gold electrode. The ability to build supramolecular architectures was also confirmed by detecting with PM-IRRAS the adsorption of streptavidin on the MUA-functionalized gold. As the approaches used for surface functionalization and its verification with PM-IRRAS are generic, one may now envisage monitoring the fabrication of tailored electrodes for a variety of applications.

Interplay of mycolic acids, antimycobacterial compounds and pulmonary surfactant membrane: A biophysical approach to disease

“…This allowed the simultaneous measurements of spectra for the two polarizations, and their difference provides surface-specific information, while their sum provides the reference spectrum (buffer with or without antimycobacterial compound). In this work, PM-IRRAS was elected due to the advantages over the conventional IRRAS mode, namely the independence of modulated reflectivity of the isotropic adsorption from the vapor or bulk water, overcoming the problem of the surrounding water vapor [36,37].…”

Cantilever Nanobiosensor Functionalized with Tyrosinase for Detection of Estrone and β-estradiol in Water

“…This peak decrease in absorption at 1650 cm −1 was attributed to the loss of carbonyl groups (C=O) with the enzyme attachment. The peak at 2300 cm −1 is characteristic of O-H stretching of carboxylic acid [13]. The PM-RAIS spectra confirmed that amine 3, characteristic of the enzyme, reacted with the NHS active esters, resulting in a modification of the peak at 2350 cm −1 .…”

Evaluation of the Structure–Activity Relationship of Rifabutin and Analogs: A Drug–Membrane Study

“…PM-IRRAS was used due its advantages over the conventional IRRAS mode, namely, the independence of the modulated reflectivity of the isotropic adsorption from bulk water or water vapor, which allows the problem of the surrounding water vapor to be overcome. [21,23] …”

“…[21,47] Moreover, PM-IRRAS allows monitoring of the vibrational spectra of the characteristic head groups of the phospholipids, such as phosphate and carbonyl present at the air/solution interface during compression of the monolayer. [21,23] The band positions of the asymmetric phosphate and carbonyl stretching vibrations in the EPC:CHOL monolayer in the absence and presence of the antimycobacterial compounds are listed in Table 2. Analysis of the phosphate and carbonyl bands is of special interest and allowed the interactions of the antimycobacterial compounds with the polar phospholipid head groups to be monitored.…”