Novel Morphology-Controlled Hierarchical Core@Shell Structural Organo-Layered Double Hydroxides Magnetic Nanovehicles for Drug Release

Abstract

Novel hierarchical core@shell structured salicylate (SA) intercalated ZnAl-LDH (layered double hydroxides) magnetic nanovehicles were obtained via a special double-drop coprecipitation strategy assembling organo-ZnAl-LDH nanocrystals onto the surface of Fe3O4 submicrospheres (∼480 nm) from cheap aspirin and Zn- and Al-nitrates in alkaline solutions. The obtained Fe3O4@SA-LDH-r nanovehicles exhibit varied morphologies with hexagonal LDH ab-face horizontal, vertical, and vertical/slant/horizontal to the surfaces of Fe3O4 upon proper mass ratio (r) of Zn-salt to Fe3O4 from 1.93 to 7.71 in a low supersaturation system and possess moderate drug loadings and strong superparamagnetism. An in vitro release study reveals that under "no MF" mode (without external magnetic field) the SA release exhibits the higher accumulated release amount and smaller half-life (t0.5) for Fe3O4@SA-LDH-3.85 (41.2%, 1.63 min) and Fe3O4@SA-LDH-7.71 (51.1%, 1.66 min) probably owing to their mainly vertical LDH orientations, while the dramatically reduced SA release (10.0%) and greatly elongated t0.5 (25.6 min) for Fe3O4@SA-LDH-1.93 may be due to its relatively stronger host-guest interaction and compact horizontally oriented LDH shell stack. Under "MF on" mode, all the magnetic samples show a detectable reduced SA release owing to the particle-particle interactions among the magnetic nanovehicles. The kinetic fittings show that the release processes of all the samples involve the bulk and surface diffusion. The SA release from Fe3O4@SA-LDH-1.93 is mainly determined by the interparticle diffusion among the horizontally oriented LDH shell nanocrystals while those of Fe3O4@SA-LDH-3.85 and Fe3O4@SA-LDH-7.71 mainly involve the interlayer intraparticle diffusion between LDHs layers due to their largely vertical LDH shell nanocrystals.

Dissolvable layered double hydroxide as a sorbent in dispersive micro‐solid phase extraction for the determination of acidic quinolones in honey by HPLC

“…The crystalline structure of LDH was investigated by XRD and the spectrum pattern was shown in Figure . The intense and sharp diffraction peaks around 11.6, 23.4, 34.5, 39.1, 46.6, 60.1, and 61.4° was ascribed to the (003), (006), (012), (015), (018) (110), (113) planes of the LDH crystal structure . Three distinguishable (003), (006), and (012) reflections were observed, which could be attributed to the typical Zn‐Al LDH structure .…”

Enhanced adsorption of anionic diazo dye by magnetic layered double hydroxide (Zn0.5Cu0.5Fe2O4@SiO2@Ni-CrLDH) from aqueous solution

“…Also, the band at 1636 cm -1 is attributed to the H−O−H deformation mode [24]. An intense absorption at 1381 cm -1 of the spectra of Zn0.5Cu0.5Fe2O4@SiO2@Ni−CrLDH are ascribed to the asymmetric stretching of nitrate anion in the interlayer of Ni−CrLDH [25]. The very strong and broad IR band at 1111 cm -1 with a shoulder at 1188 cm -1 is usually assigned to the Si−O−Si asymmetric stretching vibrations that is decreased in the FT-IR of Zn0.5Cu0.5Fe2O4@SiO2@Ni−CrLDH due to the successful coating of the Zn0.5Cu0.5Fe2O4@SiO2 sample with LDH layer.…”

Sólidos básicos como catalizadores en la síntesis ecoeficiente de heterociclos potencialmente activos

“…En la región alrededor de los 1000 cm El cambio en las intensidades de la fase hidrotalcita, cuando es combinada con las nanopartículas magnéticas, es evidencia de un ensamblaje con buena orientación de las láminas y se considera consistente con los ejes que son paralelos a la superficie de Fe3O4, este resultado también fue observado en el sólido Fe3O4@MgAl-LDH@Au [172]. Sin embargo, se observa una mejor cristalinidad para Fe3O4-HDL-Mg. Esta apreciación se relaciona con lo reportado por Chen y colaboradores, ellos sintetizaron compuestos de Fe3O4@HDL con diferentes morfologías, ajustando la relación metanol-agua, que se utiliza para la dispersión de las nanopartículas en el inicio del proceso de síntesis, encontrando que la relación 1:1 metanol-agua permite la obtención de una morfología con orientación mixta de las capas laminares, y que cuando se realiza la dispersión sin metanol, se obtiene una morfología orientada verticalmente [173,174].…”

“…La muestra correspondiente a la magnetita (a) presenta una banda de absorción a 588 cm -1 , que se atribuye a vibraciones de latencia del enlace Fe-O de Fe3O4 [173,175]. Las bandas a 795 y 895 cm -1 , se asignan a vibraciones del enlace Fe-OH que se relacionan con la fase α-FeOOH, que es característica de la mezcla de óxidos de hierro [176].…”

“…La banda a 3488 cm -1 , se atribuye al modo de estiramiento de los grupos -OH de la superficie laminar o de las moléculas de agua del espacio interlaminar. Las moléculas de agua también se pueden confirmar con la banda a los 1646 cm -1 , que se asigna al modo vibracional de deformación H-O-H, la banda a los 1395 cm -1 se asigna al estiramiento asimétrico del anión carbonato [171,173]…”