Novel synthetic routes of large-pore magnetic mesoporous nanocomposites (SBA-15/Fe₃O₄) as potential multifunctional theranostic nanodevices

Abstract

In this paper, novel magnetic silica nanocomposites were prepared by anchoring magnetite nanoparticles onto the outer surface of mesoporous SBA-15 silica; the magnetic nanoparticles were prepared by microemulsion and solvothermal methods, varying the synthesis conditions in order to control the final physicochemical, textural and magnetic properties. The morphology and mesostructure of the materials were characterized by X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), N 2 adsorption-desorption, and Transmission and Scanning Electron Microscopy (TEM and SEM). Magnetic silica nanocomposites feature a two-dimensional hexagonal arrangement constituted by a homogeneous pore channel system with diameters between 13 and 18 nm and a Brunauer-Emmett-Teller (BET) surface area higher than 260 m 2 g À1 . The different morphologies of the samples are given by the presence of diverse magnetic nanoparticle arrangements covalently linked onto the outer surface of the mesoporous silica rods. This confers on them a superparamagnetic behaviour with a magnetic response between 50-80 emu g À1 , even though the weight percent of magnetite present in the samples does not exceed 21.7%. In addition, the magnetic nanocomposites exhibit magnetic hyperthermia with moderate Specific Absorption Rate (SAR) values.

Catalytic evaluation of copper (II)N‐salicylidene‐amino acid Schiff base in the various catalytic processes

“…The later constant is related to the energy of adsorption in the first adsorbed layer. The BET relation is applicable in the relative pressure range ( P / P o = 0.05−0.3) for the surface area of non‐, macro‐ and meso‐porous materials isotherm . Figure assigned the BET surface area plot of Fe 3 O 4 ‐SiO 2 ‐Cu‐PST.…”

Multifunctional Superparamagnetic Stiff Nanoreservoirs for Blood Brain Barrier Applications

“…SBA-15 mesoporous silica nanorods (S15N) were obtained under strongly acidic conditions from the condensation of hydrolyzed silica precursors in the presence of a soft template composed by a mixture of Pluronic P123, a triblock copolymer surfactant, and glycerol, as previously reported [32]. Afterwards, magnetic functionality was added by covalently anchoring [33] magnetite nanoparticles to the S15N surface by coating all with an aminated silica grafting (Figure 1) while the optical response was achieved by linking a dense fluorescent moiety layer (rhodamine B isothiocyanate) to the surface amines of the HMMSN sample.…”

“…Afterwards, magnetic S15N nanorods, HMMSN, were obtained by covalently anchoring magnetite NPs over mesoporous silica nanorods [33]. For this, a previously prepared solution (2.4 mL) of oleic acid-capped magnetite nanoparticles [Fe 3 O 4 @OA] stabilized in cyclohexane at 3.5% ( w / v ) was poured into a 7.6% solution of Igepal CO-520 in cyclohexane (266.16 mmol), at a 1:12.5 volume ratio, and stirred for 30 min.…”

Fenton and Photo-Fenton Nanocatalysts Revisited from the Perspective of Life Cycle Assessment

“…Fe 3 O 4 @SiO 2 core-shell nanoparticles were prepared through a water-in-cyclohexane reverse microemulsion starting from the oleic-acid-coated magnetite nanoparticles [25], using as main chemicals: polyoxyethylene(5)nonylphenyl ether (Igepal CO-520), cyclohexane, NH 4 OH, TEOS and isopropanol (IPA) [29]. Beyond the consumption of chemicals and the energy consumption associated with mechanical stirring and drying (60 • C), the consumption of distilled water and cyclohexane for washing and redispersion were also included.…”

“…This procedure was based on the formation of silica-coated NPs in water-in-oil microemulsion systems, but including the SBA-15 matrix to favor the anchoring of Fe 3 O 4 @SiO 2 on the external surface of the SBA-15 matrix [29]. Finally, the reaction was continued at room temperature for 16 h, under mechanical stirring and in the dark.…”