Magnetic Nanoparticles-Templated Assembly of Protein Subunits: A New Platform for Carbohydrate-Based MRI Nanoprobes

Abstract

A new approach for the preparation of carbohydrate-coated magnetic nanoparticles is reported. In a first step, we show that the pH-driven assembly-disassembly natural process that occurs in apoferritin protein is effective for the encapsulation of maghemite nanoparticles of different sizes: 4 and 6 nm. In a second step, we demonstrate that the presence of functional amine groups in the outer shell of apoferritin allows functionalization with two carbohydrates, N-acetyl-D-glucosamine and d-mannose. High-resolution electron microscopy (HREM), high angle annular dark field scanning electron microscopy (HAADF-STEM), electron energy loss spectroscopy (EELS), X-ray diffraction (XRD), and SQUID technique have been used to characterize the magnetic samples, termed herein Apomaghemites. The in vivo magnetic resonance imaging (MRI) studies showed the efficiency in contrasting images for these samples; that is, the r(2) NMR relaxivities are comparable with Endorem (a commercial superparamagnetic MRI contrast agent). The r(2) relaxivity values as well as the pre-contrast and post-contrast T(2)*-weighted images suggested that our systems could be used as perspective superparamagnetic contrast agents for magnetic resonance imaging (MRI). The carbohydrate-functionalized Apomaghemite nanoparticles retained their recognition abilities, as demonstrated by the strong affinity with their corresponding carbohydrate-binding lectins.

Apoferritin–CeO2nano-truffle that has excellent artificial redox enzyme activity

“…1a). 8,9 To the best of our knowledge, the nano-CeO 2 , with all the faces being the most chemically active (100) facet and a narrow size distribution centered around 4.5 nm (Fig. S1, ESIw), have not been synthesized before.…”

Physiological origin of biogenic magnetic nanoparticles in health and disease: from bacteria to humans

“…178 Worthy of note are also other considered approaches based on the disassembly of the apoferritin shell and its reassembly in the presence of the species to be encapsulated. [183][184][185] Besides the possible applications of synthetic ferritin in electronics 186 and biomedicine, 119,120 the interest in this unique material has been stimulated also by its role as the artificial modeling object for the development of methods for the determination and study of the physical and chemical properties of the hypothetical precursor of BMNPs.…”

“…On the other hand, purified ferritin cages in vitro can incorporate a variety of metal ions (Fe, Au, Pd, Rh, Pt, Ni, Cr, Cd, Ti, Tb, Co, Cu, and Zn), most likely through a hydrophilic threefold ion channel. 183,223,224 Therefore, both ferritin and BMNPs might contribute to the excess of zinc and copper in neurodegenerative disorders. 225 …”

Bioinspired Magneto-optical Bacteria

“…[38][39] However, once they are incorporated into the external bacterial surface, dipoledipole interactions occur due to the close mutual proximity of the maghemite particles so that the maghemite-gold bacteria behave as ferromagnets at room temperature. This behavior is consistent with results that we have reported previously, in which massive incorporation of maghemite nanoparticles onto the bacteria surface yielded increased magnetic properties.…”

“…38 Quantification of bacterial proliferation was performed using Live/Dead Bacterial Viability Kits SYTO9 (green) and propidium iodine (red), by counting the number of live (green) and dead (red) bacteria. The average live/dead ratio was used to quantify the effect of gold and maghemite nanoparticles upon bacterial proliferation by comparing with control cultures in the absence of nanoparticles.…”