Nanocrystals of Zn(Fe)O-based diluted magnetic semi-conductor as potential luminescent and magnetic bimodal bioimaging probes

Abstract

Nanocrystals of Zn(Fe)O-based diluted magnetic semi-conductor (nanoDMS) have been prepared by forced hydrolysis in polyol medium, using zinc and iron salts, and coated with carboxymethylpullulan (CMP). TEM studies revealed that CMP-nanoDMS are spherical, with average diameters on the order of 20 nm. Hydrodynamic diameters of about 75 nm were found in a physiological medium. NanoDMS were superparamagnetic at body temperature, and exhibited high saturation magnetization values (3.25 emu g À1 ). In aqueous suspensions, the colloids revealed high transverse proton relaxivities (T 2 ) with an r 2 value of 203 mM À1 s À1 (300 K, 1.41 T). Visible photoluminescent properties were evidenced with an excitation wavelength of 366 nm. No evidence of cell toxicity was found for human endothelial cells incubated with CMP-nanoDMS, at concentrations up to 100 mg mL À1 and for 48 h. No modification to the cytoskeleton was found up to 6 days of exposure. These hybrid nanomaterials could be considered as novel potential MR and luminescent bioimaging agents.

Bimodal Fucoidan-Coated Zinc Oxide/Iron Oxide-Based Nanoparticles for the Imaging of Atherothrombosis

“…Compared with the other preparations, the additional signal between 46° and 53°, which corresponds to an indexation (400) of the cubic phase, made it possible to conclude that the two Zn 0.54 (Fe) 0.46 O and ZnFe 2 O 4 phases were mixed with a molar proportion determined by refinement of 2.57: 1. In previous works using polyol method the NPs sizes were higher than those obtained in our study: Balti et al: 17 nm [ 20 ], Dinesha et al: 19–34 nm [ 21 ], Ciciliati et al: 11–25 nm [ 31 ], Il’ves et al: 10–20 nm [ 13 ] and Arciniegas-Grijalba et al: 20–35 nm [ 32 ]. Moreover, irrespective of the synthesis method, other studies have observed that the size of Zn(Fe)O NPs decreased with the increase of iron concentration and they noted also the formation of a secondary phase-spinel ZnFe 2 O 4 increasing with the concentration of Fe doping and with the annealing temperature [ 13 ].…”

“…The formation of Zn(Fe)O crystals without modification of the elementary cell, i.e., leading to the same crystal lattice, is obtained either by substitution of some zinc ions by iron ions or by inclusion of iron ions into tetraedric sites of the hexagonal cell [ 20 , 21 ]. For NP-0.50, we tried to propose a stoichiometry for the hexagonal phase by making the hypothesis of substitution.…”

“…Zn(Fe)O have been synthesized by many ways [ 13 ], the most popular approach being the polyol method [ 14 ] which makes it possible to solubilize a large number of metallic precursors and to efficiently activate the reactions favoring particles with a high crystallinity and a narrow size distribution [ 15 , 16 ] and Fe 3 O 4 @ZnO [ 17 , 18 ], and ZnO nanorods decorated with γ-Fe 2 O 3 have been proposed [ 19 ]. The formation of Zn(Fe)O nanocrystals without modification of the elementary cell, i.e., leading to the same crystal lattice, could be obtained either by substitution of some zinc ions by iron ions, or by the inclusion of iron ions into tetrahedral sites of the hexagonal wurtzite cell [ 20 , 21 ]. ZnO-based nanocrystals doped with up to 25 wt% Fe synthesized by the polyol method have been reported with a size of 17 nm and a narrow size distribution [ 20 ].…”

“…The formation of Zn(Fe)O nanocrystals without modification of the elementary cell, i.e., leading to the same crystal lattice, could be obtained either by substitution of some zinc ions by iron ions, or by the inclusion of iron ions into tetrahedral sites of the hexagonal wurtzite cell [ 20 , 21 ]. ZnO-based nanocrystals doped with up to 25 wt% Fe synthesized by the polyol method have been reported with a size of 17 nm and a narrow size distribution [ 20 ]. Eventually, a drastic reduction of the toxicity of iron-doped ZnO by comparison with pure ZnO nanocrystals was observed in rodent and zebrafish models up to an iron content of 10 wt% Fe [ 22 ].…”

Hexamethylene‐1,3‐bis(cetyldimethylammonium bromide) protected low‐toxicity ZnSe quantum dots as fluorescent probe for proteins

“…Semiconductor nanocrystals, known as 'quantum dots' (QDs), have high luminescence efficiency, continuous excitation spectrum, high stability against photobleaching, controllable and narrow emission bands compared with the traditional organic fluorescent dyes, due to the quantum confinement effects [13][14][15][16]. Thus, they are ideal fluorescent dyes to replace organic fluorescent dyes and have attracted increasing interest for bioimaging [17], biolabelling [18], biodetection [19] and clinical diagnosis [20]. Compared with the traditional CdSe QDs that have toxicity in certain conditions [21], ZnSe QDs (without heavy metal ions) are potential blue fluorescent biological labels because of their low cytotoxicity [22][23][24][25].…”