Impact of the Presence of Octadecylamine on the Properties of Hydrothermally Prepared CoFe₂O₄ Nanoparticles

Abstract

CoFe 2 O 4 magnetic nanoparticles (MNPs) were synthesized in a new synthetic system from metal acetylacetonates in the presence of octadecylamine (ODA) in autoclaves with subcritical water. By altering the water extent and ratio of the precursors, four samples were isolated. High crystallinity MNPs of various sizes (26, 15, 18, 9 nm) and saturation magnetization (71, 87, 93, 64 emu g -1 ) were formed. The organic coating was characterized by FTIR spectroscopy, 1 H NMR and 13 C NMR spectroscopy, and thermogravimetric analysis (TGA), and the free amine groups were detected by a ninhy- [a]3645 drin assay. Under the present conditions, the CoFe 2 O 4 MNPs were covered by a bilayer consisting of N-octadecylamide and ODA. The MNPs were converted into fluorescence probes through the formation of a sulfonamide bond between ODA and sulforhodamine B (SRB). NMR relaxometric measurements were performed for MNPs modified with SRB, cetyltrimethylammonium bromide, and by 2,3-dimercaptosuccinic acid. The bimodal magnetic fluorescent MNPs showed relaxivity values of up to r 2 = 219.5 mM -1 s -1 , which renders them promising as dual agents.

Nanoplatforms of Manganese Ferrite Nanoparticles Functionalized with Anti‐Inflammatory Drugs

“…We have shown before that based on the synthetic conditions, the linear configuration of ODA molecules can lead to unshielded NH 2 groups on the surface of CoFe 2 O 4 MNPs . In the present study we tested if this efficacy is present in case of MnFe 2 O 4 MNPs in addition to the prerequisites of size, crystallinity, magnetization.…”

Octadecylamine-Mediated Versatile Coating of CoFe2O4 NPs for the Sustained Release of Anti-Inflammatory Drug Naproxen and in Vivo Target Selectivity

“…Aliquots of 0.1–0.6 mL of ODA (0.25 mg mL –1 ) in DMF were pipetted into a series of tubes . Ninhydrin solution (0.7 mL) in MeOH 0.06 M (10.7 mg mL –1 ) was added in each tube, mixed well, and heated in a water bath at 100 °C for 5 min.…”

Diverse Surface Chemistry of Cobalt Ferrite Nanoparticles to Optimize Copper(II) Removal from Aqueous Media

“…The concentration of the free amine groups on the MNPs' surface was determined by a ninhydrin colorimetric assay [39]. The method is based on the formation of Ruhemann's purple complex, which is indicative of the reaction between amino groups and ninhydrin.…”