Dextran-coated magnetic nanoclusters as highly sensitive contrast agents for magnetic resonance imaging of inflammatory macrophages

Abstract

We fabricated dextran-coated magnetic nanoclusters (Dex-MNCs) for targeted magnetic resonance (MR) imaging of inflammatory macrophages. Dex-MNCs were prepared through encapsulation of hydrophobic magnetic nanocrystals (MNCs) by pyrenyl dextran in order that MNCs could achieve increased colloidal stability in aqueous phase as well as strongly interact with macrophages. Dex-MNCs exhibited biocompatibility and sufficient targeting efficiency against macrophages with strengthened MR contrast effect from in vitro/in vivo studies. Considering these results, we confirmed that Dex-MNCs could accurately detect inflammatory macrophage via MR imaging.

Colloidal magnetic nanocrystal clusters: variable length-scale interaction mechanisms, synergetic functionalities and technological advantages

“…Adding a solvent in which the polymer was insoluble yielded small secondary structures, while adding a solvent in which the polymer is soluble allowed for larger structures embedding a large number of primary nanocrystals to be formed. Different types of molecules, as encapsulating agents of iron oxide nanoparticles, have been used, including polymers/block copolymers ( Figure 6A, B) [24,99,98,101,94], micelles ( Figure 6C) [100], polysaccharides [22,32], or hydrogels [95]. For example, aggregated iron oxide particles with controlled size have been prepared by utilizing methods based on acid/base interactions involving pre-formed nanocrystals in an organic solvent ( Figure 6C) [100].…”

“…Different morphologies, compact or loose structures with diameters ranging from 30 to a few hundred nm have been obtained with the previous synthesis strategies. Colloidal assemblies of inorganic nanocrystals are commonly called nanoclusters [15,[21][22][23][24][25][26][27][28][29], but in the literature, they can also be found as nanoflowers [30], nanoroses [17], multi-core particles [31,32], nanoassemblies [13,14,33,34], porous particles [35], flower-like mesocrystals [36], nanobeads [37,38], and pomegranate-like particles [34]. Furthermore, it is worth noting that these can be delivered with diverse chemical origin, including nanoclusters of ZnO [39,40], Co 3 O 4 [41], CuO [42], In 2 O 3 [40], CoO [40], MnO [40], ZnSe [40], CuCr 2 S 4 [43], PbS [44], and TiO 2 [45].…”

One-pot synthesis of magnetic nanoclusters enabling atherosclerosis-targeted magnetic resonance imaging

“…Pyrenyl dextran was first synthesized as a stabilizer by esterification of 1-pyrenebutyric acid as a hydrophobic moiety and dextran as a hydrophilic moiety using DCC and 4-dimethylaminopyridine (see Figure S1). 32,33 Synthesis of pyrenyl dextran was confirmed by Fouriertransform infrared and 1 H-NMR spectra. Generation of its ester group was observed as an absorption peak at 1,727 cm −1 in the Fourier-transform infrared spectra (see Figure S2).…”

“…32,33 The hydroxyl group of dextran (molecular weight 10,000 Da) was linked to the carboxylic group of 1-pyrenebutyric acid (molecular weight 288.34 Da) using DCC and DMAP as the coupling agent and catalyst, respectively (Figure 1). A mixture of 0.1 mmol of dextran, 4.2 mmol of 1-pyrenebutyric acid, 0.5 mmol of DCC, 0.5 mmol of 4-dimethylaminopyridine, and 0.2 mmol of triethylamine dissolved in 60 mL of dimethyl sulfoxide was reacted for 48 hours at room temperature followed by lyophilization.…”

“…[31][32][33][34][35][36][37] Pyrenyl dextran, used as a surfactant, was first synthesized using dextran and 1-pyrenebutyric acid, as previously reported. 32,33 The DMNCs were then synthesized with iron precursors and pyrenyl dextran in the solution phase. We confirmed the physicochemical properties of DMNCs and their usefulness as MR imaging agents for detection of atherosclerosis using in vitro/in vivo systems (Figure 1).…”