Aqueous synthesis of magnetite nanoparticles for magnetic hyperthermia: Formation mechanism approach, high water-dispersity and stability

Magnetite Nanoparticles Coated with Biodegradable Zwitterionic Polymers as Multifunctional Nanocomposites for Drug Delivery and Cancer Treatment

“…9 The XRD pattern of the sample (Figure S1a, see the Supporting Information) shows the characteristic peaks assigned to the magnetite phase corresponding to the standard pattern diffraction JCPDS 19-0629. A previously detailed structural study 9 S1b reveal spherical nanoparticle formation with an average 9.5 ± 1.9 nm (D TEM ± SD) diameter. A polydispersity index (σ = SD/D TEM ) of 0.2 indicates a narrow size distribution in a monodisperse-like system.…”

“…The naked magnetite spectrum shows the characteristic band at 580 cm −1 assigned to the Fe−O stretching and a discreet shoulder at 640 cm −1 attributed to the Fe−O stretching band due to structural vacancies, leading to some nonstoichiometric magnetite phase. 9 The additional bands at 870 and 1015 cm −1 are assigned to adsorbed sulfur groups onto the nanoparticle's surface, respectively, regarding ν(S−O) and ν(S�O). The black arrows identify the iron and sulfur bands in Figure S12c.…”

“…The magnetite synthesis was performed as previously reported . Briefly, appropriate volumes of 1 mol L –1 FeCl 3 (in an acidic medium) and 1 mol L –1 Na 2 SO 3 aqueous solutions ([Fe 3+ ]/[SO 3 2– ] = 3) were mixed, resulting in a red-colored [Fe-SO 3 ] complex.…”

“…After 470 s, the magnetic field was turned off, and the temperature was registered for more than 30 s. The ability of the samples to absorb energy from an alternating field is quantified by SAR (Specific Absorption Rate, (W g –1 )), also known as SLP (Specific Loss Power). First, the time-dependent heating curve was fitted with a Box–Lucas-type equation , normalΔ T = a 0.25em ( 1 − e ( − b false( t − t 0 false) ) ) where Δ T , t 0 , and t are the temperature variation, initial time, and actual time, respectively. The adjustable parameters a and b are used to calculate the SAR values (eq ) SAR false( normalW 0.25em normalg − 1 false) = C m a 0.25em b where C is the heat capacity of the suspension (4.184 J g –1 °C –1 for diluted aqueous dispersion) and m is the concentration of the nanoparticle suspension in g mL –1 .…”

“…This alternative and complementary cancer treatment is currently applied to brain tumors . However, some challenges still prevent SPIONs from expressing their full potential: a simple, reproducible, and inexpensive methodology allowing large-scale production with useful physicochemical features suitable for hyperthermia applications . Nevertheless, the technological challenge lies in the surface engineering of SPIONS, concerning solving the problems of (i) injectability, colloidal stability, biocompatibility, and increase in circulation time; (ii) introduction of tissue targeting and recognition agents, improving the accumulation or internalization in tumor cells; and (iii) coatings that potentiate the loading and release of anti-inflammatory and antineoplastic agents …”