Nature of Interactions of Amino Acids with Bare Magnetite Nanoparticles

Abstract

Owing to their chemical and magnetic properties, magnetite nanoparticles are an interesting adsorbing material for biomolecules. The understanding of the interactions of simple biomolecules with inorganic nanoparticles is an important approach for research on the bio-nano interface and can constitute the fundamentals to manifold applications in biotechnology, medicine and catalysis. The aim of the work presented here is to compare the interaction of seven different amino acids (L-alanine, L-cysteine, Lglutamic acid, glycine, L-histidine, L-lysine, and L-serine) with magnetite nanoparticles in a colloidal system at pH 6. We investigate the influence of the side chain on the adsorption at a magnetite−water interface with incubation experiments. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and simultaneous thermal analysis (STA) reveal deeper insights into the interactions of amino acids with magnetite nanoparticles. The amino acids that contain polar side chains adsorb on the nanoparticles to a high degree. Cysteine demonstrates the highest adsorption capacity and the formation of cystine is observed. ATR-FTIR spectroscopy results indicate a strong influence of the carboxyl group and side chains on the binding mechanism of amino acids at the iron oxide surface. Our investigation offers novel knowledge into adsorption behavior at the bio-nano interface.

Hydrophobic Forces Are Relevant to Bacteria-Nanoparticle Interactions: Pseudomonas putida Capture Efficiency by Using Arginine, Cysteine or Oxalate Wrapped Magnetic Nanoparticles

“…For all NPs synthetized in this study, we detected stretching signals corresponding to carboxyl group vibrations. In particular, C=O stretching and C-O-H in plane bending signals corresponding to the carboxylic acid can be observed at values closed to 1600 cm −1 and 1400 cm −1 , respectively [18,24,27]. We found a carbonyl signal at 1634 cm −1 for Fe3O4@Oxa, 1624 cm −1 for Fe3O4@Cys and 1653 cm −1 for Fe3O4@Arg; we also found C-O-H in plane bending signals at 1403 cm −1 for Fe3O4@Oxa, 1398 cm −1 for Fe3O4@Arg and 1408 cm −1 for Fe3O4@Cys.…”

“…For all NPs synthetized in this study, we detected stretching signals corresponding to carboxyl group vibrations. In particular, C=O stretching and C-O-H in plane bending signals corresponding to the carboxylic acid can be observed at values closed to 1600 cm −1 and 1400 cm −1 , respectively [18,24,27]. We found a carbonyl signal at 1634 cm −1 for Fe 3 2− equal to 2:1:1 was used in the first synthesis step, but when molar ratio was 2:1:0.1, as Tie et al used [24], these signals did not appear ( Figure S2).…”

“…In the case of pure cysteine (Figure 5a), the weak stretching signal at 2561 cm −1 belongs to S-H, which commonly appears near 2500 cm −1 [18]; however, these stretching signals were not present for Fe 3 O 4 @Cys. In the study of Schwaminger et al [18], they show that cysteine absorbed to magnetite and can form S-S bonds between them, and this can be seen in the stretch between 500 and 530 cm −1 [29]. Figure 5b shows the presence of S-S signal at 539 cm −1 , suggesting that there is a molecular bond between two cysteine molecules over the surface of the NP.…”

Adsorption of Amino Acids, Aspartic Acid, and Lysine onto Iron-Oxide Nanoparticles

“…Different AAs have been applied to prepare stable suspensions of iron-oxide nanoparticles. [19][20][21][22][23][24][25][26] It was also proposed that the adsorbed AAs can be used for the functionalization of nanoparticles, providing specific functional groups at the nanoparticle surfaces for the subsequent conjugation of different molecules. 19,20,23 As AAs play a very important role in the body, their adsorption onto the magnetic nanoparticles was proposed to aid their targeted delivery.…”

Green synthesis and characterisation of L-Serine capped magnetite nanoparticles for removal of Rhodamine B from contaminated water

“…So, it is still a great challenge to develop biocompatible synthesis methods. More recently, amino acids have been showing a fascinating interest because of their biocompatibility and good capping capability towards Fe 3 O 4 NPs [18,19]. Syntheses of Fe 3 O 4 NPs with amino acids as a capping agent have often done in the absence of toxic organic solvents which increases the popularity of amino acids as capping materials [19].…”