Thin Films of Lanthanide Stearates as Modifiers of the Q-Sense Device Sensor for Studying Insulin Adsorption

Abstract

This article presents new possibilities of using thin films of lanthanide stearates as sorbent materials. Modification of the Q-sense device resonator with monolayers of lanthanide stearates by the Langmuir–Schaeffer method made it possible to study the process of insulin protein adsorption on the surface of new thin-film sorbents. The resulting films were also characterized by compression isotherms, chemical analysis, scanning electron microscopy, and mass spectrometry. The transition of stearic acid to salt was recorded by IR spectroscopy. Using the LDI MS method, the main component of thin films, lanthanide distearate, was established. The presence of Eu 2+ in thin films was revealed. In the case of europium stearate, the maximum value of insulin adsorption was obtained, −1.67·10 −10 mole/cm 2 . The findings suggest the possibility of using thin films of lanthanide stearates as a sorption material for the proteomics determination of the quantitative protein content in complex fluid systems by specific adsorption on modified surfaces and isolation of such proteins from complex mixtures.

Surface Modification of NiO‐Al2O3 Nanocomposites using Stearic Acid as a Modifier and their Applications in Self‐cleaning and Removal of Dyes

“…In unmodified NiO‐Al 2 O 3 nanocomposite, the bands at 3566–3457 cm −1 and 1640 cm −1 are due to stretching and bending vibrations of hydroxyl groups of physisorbed water molecules, respectively. The bands at 812 cm −1 and 551 cm −1 are attributed to Al‐O and Ni‐O stretching vibrations, respectively [68–69] . In the free stearic acid, the IR bands observed at 2928 cm −1 , 2852 cm −1 , and 1705 cm −1 are assigned to asymmetric (−CH 2 ) and symmetric (−CH 2 ) stretching and C=O group of COOH, respectively [40] …”

“…The bands at 812 cm À 1 and 551 cm À 1 are attributed to Al-O and Ni-O stretching vibrations, respectively. [68][69] In the free stearic acid, the IR bands observed at 2928 cm À 1 , 2852 cm À 1 , and 1705 cm À 1 are assigned to asymmetric (À CH 2 ) and symmetric (À CH 2 ) stretching and C=O group of COOH, respectively. [40] In the IR spectra of stearic acid-modified NiO-Al 2 O 3 samples (NA(SA1), NA(SA2), and NA(SA3)), the band due to stretching vibration of COOH (at 1705 cm À 1 ) disappears and two new IR bands at 1552 cm À 1 and 1414 cm À 1 attributed to asymmetric and symmetric stretching of COO À group appear.…”

Holmium-Containing Metal-Organic Frameworks as Modifiers for PEBA-Based Membranes

“…Membranes and thin solid films with metal ions [ 32 , 33 , 34 ] have been used in many fields, such as seawater desalination, wastewater treatment and gas separation [ 35 , 36 , 37 ]. Most modern research into the use of membrane technologies for the separation of components is based on the use of mixed matrix membranes (MMMs) containing various additives, such as metal oxides, fullerene and its derivatives, MOFs, etc.…”