Chemical and Colloidal Stability of Carboxylated Core-Shell Magnetite Nanoparticles Designed for Biomedical Applications

Abstract

Despite the large efforts to prepare super paramagnetic iron oxide nanoparticles (MNPs) for biomedical applications, the number of FDA or EMA approved formulations is few. It is not known commonly that the approved formulations in many instances have already been withdrawn or discontinued by the producers; at present, hardly any approved formulations are produced and marketed. Literature survey reveals that there is a lack for a commonly accepted physicochemical practice in designing and qualifying formulations before they enter in vitro and in vivo biological testing. Such a standard procedure would exclude inadequate formulations from clinical trials thus improving their outcome. Here we present a straightforward route to assess eligibility of carboxylated MNPs for biomedical tests applied for a series of our core-shell products, i.e., citric acid, gallic acid, poly(acrylic acid) and poly(acrylic acid-co-maleic acid) coated MNPs. The discussion is based on physicochemical studies (carboxylate adsorption/desorption, FTIR-ATR, iron dissolution, zeta potential, particle size, coagulation kinetics and magnetization measurements) and involves in vitro and in vivo tests. Our procedure can serve as an example to construct adequate physico-chemical selection strategies for preparation of other types of core-shell nanoparticles as well.

Hemocompatibility and Biomedical Potential of Poly(Gallic Acid) Coated Iron Oxide Nanoparticles for Theranostic Use

“…The pH of magnetite dispersions was adjusted to ∼6.5 and GA was added in concentration of 0.6 mmol GA/g magnetite. The pH was readjusted subsequently for five weeks, during which period GA polymerized at the surface as it is demonstrated in [21,22]. The sample was stored in dark at 4 o C. The values of electrokinetic potential (-40 mV), hydrodynamic diameter (∼170 nm, as compared to that of naked MNPs of ∼100 nm) and critical coagulation concentration (500 mM, while that of naked MNPs of is only 1 mM) revealed the presence of a thick coating layer, which in turn, stabilizes the particles even in the presence of salt at high concentrations.…”

“…Magnetite (Fe 3 O 4 ) nanoparticles were synthesized by alkaline hydrolysis of iron(II) and iron(III) salts [22]. Briefly, the concentrated iron salt solutions were mixed at the ratio of 1:2 and precipitated by NaOH solution.…”

“…The PGA@MNPs for the biomedical tests were prepared on the basis of GA adsorption experiments detailed by us earlier [21,22]. The PGA@MNP dispersions were prepared at a concentration of 15 g/L in aqueous medium.…”

“…This way, the synthesis of PGA@MNPs would proceed in an all-natural soft method and the emergence of toxic by-products would be excluded. The PGA@MNPs have indeed been successfully produced and we have published their physico-chemical and colloidal characterization relevant to possible biomedical applications [20][21][22]. In the present study, we utilized in vitro experiments for testing the biodistribution, biocompatibility and antioxidant capacity of the polygallate stabilized SPION product.…”

Investigation of removal possibilities of chromium(III) oxide from water solution in the presence of albumins

“…There are few studies on this subject in the literature. Wells et al (2011) described the stability of iron(III) and zinc oxide nanoparticle suspensions in the serum protein presence, and Szekeres et al (2013) determined the modified magnetite suspension stability. However, their main purpose was to check the possibility of medical applications.…”