Magnetic nanoparticles (NPs) are especially interesting for several biomedical applications due to their chemical surface, especially for targeted cancer imaging and therapeutics. In order to realize these applications, it is important to know their magnetic properties among other complementary properties that help to improve the understanding of the synthesis process. In this work, we report the magnetic properties of polyethyleneimine-coated magnetite (PEI-Fe3O4) NPs synthesized by a one-step method via the co-precipitation method and using PEI as a stabilizer. Transmission electron microscopy (TEM) images revealed agglomerated magnetic nanoparticles with an average size of similar to 10 nm; meanwhile, the X-ray diffraction (DRX) analysis confirmed a pure magnetite phase. The study of magnetic properties shows a superparamagnetic system with coexistence of non-interacting single NPs wi...

The O-carboxymethylchitosan (O-CMQ) was derivatized from the chitosan copolymer by the direct alkylation method. This method involved the reaction of the chitosan with monochloroacetic acid after alkalinization. The derivatized product showed solubilityin a pH range of 1-13 and low solubility at pH = 5. The degree of substitution (GS) was 0,92, determined by conductometric titration. The results of Fourier Transform Infrared Spectroscopy (FT-IR) allowed us to identify a strong intensity absorption band at 1585cm-1, corresponding to the stretching of C = O, which indicates the presence of a carboxylic anion (-COO- ) that is characteristic of O-carboxymethylchitosan (O-CMQ). Using the Nuclear Magnetic Resonance spectroscopy of proton and carbon-13 (1 H NMR, 13C NMR) showed that the substitution was carried out on carbon 3 and 6 of chitosan. The derivatized O-CMQ at concentration of 50mg / ...

The synthesis of the nanocomposite based on silver nanoparticles and O-carboxymethyl chitosan (NPsAg-CMQ), by the chemical reduction method, using the O-carboxymethylchitosan 0.01% and AgNO3 1 mM in a ratio of 3: 2, with a time of 30 minute reaction, at room temperature and neutral pH. The nanocomposite obtained from the complex [Ag(NH3)2]+ was synthesized under the same conditions as AgNO3 but at a basic pH. Using UV-VIS spectrophotometry, the plasmon formation of silver nanoparticles at 410nm was verified for both silver sources. The results by Dynamic Light Dispersion (DLS) for AgNO3, shows a monodisperse distribution of the nanocomposite with an average hydrodynamic size of 166.7 nm. In the case of the diamine silver [Ag(NH3)2] + 83.9% had an average size of 54.42 nm. and 15.2% of 4.48 nm. Infrared Spectroscopy Measurements with Fourier Transform (FT-IR) shows the inhibition of the s...