Synthesis of Silica‐Coated Semiconductor and Magnetic Quantum Dots and Their Use in the Imaging of Live Cells

Abstract

Bifunctional nanocomposites comprising semiconductor and magnetic nanoparticles are of interest in biological applications for biolabeling, bioimaging, and cell separation. To this end, a nanocomposite system that consists of Fe2O3 magnetic nanoparticles and CdSe quantum dots and which exhibits superparamagnetism and tunable emission properties was prepared and used to label different live cell membranes (see picture).

Improved Biocompatibility and Pharmacokinetics of Silica Nanoparticles by Means of a Lipid Coating: A Multimodality Investigation

“…In addition to carrying contrastgenerating material for a single imaging modality, the ease of incorporation of different chemicals in silica makes it an excellent material for the integration of multiple properties to enable multimodality biomedical imaging. For example, combined FI and MRI have been shown in vitro [19][20][21][22][23] as well as in vivo. 24,25 Other promising, silica-based materials for combined FI and MRI, [26][27][28][29] combined FI and computed tomography (CT), 30 MRI and CT, 31 and even FI, MRI, and CT 32 have been reported but have not yet shown their applicability in vitro or in vivo.…”

Colloidal Magnetic Heterostructured Nanocrystals with Asymmetric Topologies: Seeded-Growth Synthetic Routes and Formation Mechanisms

“…By a reverse reaction scheme, hetero-dimers made of FePt-Au Choi et al, 2006;Shi et al, 2006b;Selvan et al, 2007;Wark et al, 2008;He et al, 2009;Franchini et al, 2010;Zeng et al, 2010;Mao et al, 2011;Krylova et al, 2012;Zhu et al, 2013), CoPt 3 -Au PazosPerez et al, 2007;Krylova et al, 2012), and Fe 3 O 4 -Ag (Zhang et al, 2006;Jiang et al, 2008;Yang and Ying, 2009;Huang et al, 2011;Peng et al, 2011;Mao et al, 2013) were generated upon reduction of Au(I)-, Au(III)-, or Ag(I)-ligand complexes onto FePt, CoPt 3 , and Fe 3 O 4 , seeds, respectively, with mild reducing agents (alkyl amines, alkyl diols, Ar/H 2 atmosphere) at moderate temperatures (<120°C) (Figures 2E-G). With the introduction of an extra reaction step, γ-Fe 2 O 3 -Cu 2 O and Au-Fe 3 O 4 heterodimer MHNCs were produced from parent γ-Fe 2 O 3 -Cu (Mirtchev et al, 2014) and Au-Fe (Jiang et al, 2016) hetero-dimers upon post-synthesis air oxidation of their Cu and Fe sections, respectively.…”

“…For example, the luminescence of semiconductor modules is severely quenched due to the metal contact promoting electron transfer, hence, decreasing the probability of radiative electron-hole recombination (de Mello Donegà, 2011;Sitt et al, 2013;Banin et al, 2014). The LSPR features of coinage-metal sections are largely modified, depending on the dielectric characteristics of their proximal neighbors Shi et al, 2006b;Yang et al, 2006aYang et al, ,b, 2009Yang and Ying, 2009;Pazos-Perez et al, 2007;Selvan et al, 2007;Wark et al, 2008;He et al, 2009;Franchini et al, 2010;Zeng et al, 2010). In addition, the relevant magnetic parameters of magnetic domains are often found to unpredictably deviate from those of the otherwise isolated components Huang et al, 2011;Mao et al, 2011;Wu et al, 2011b;Leung et al, 2012;Zhu et al, 2013), indirectly revealing an influence of interfacial electron communication on the electronic and magnetic behavior Shi et al, 2006b;Zhang et al, 2006;Pazos-Perez et al, 2007;Jiang et al, 2008;Yang and Ying, 2009;.…”

“…Detailed investigations on the formation of heterostructures based on either FePt or γ-Fe 2 O 3 and metal chalcogenides of the type MeX (Me = Cd, Zn, Hg; X = S, Se) (Gu et al, 2004;Kwon and Shim, 2005;Kwon et al, 2006;Selvan et al, 2007;Zanella et al, 2008;He et al, 2009;McDaniel and Shim, 2009) have revealed that interfacial strain emerging upon crystallization and induced coalescence in the early post-deposition stages impacted on their topological evolution ( Figure 3A). Examples of hetero-dimer and hetero-oligomer HNCs derived from these pathways are displayed in Figures 3B-E.…”

“…Upon prolonged heating at 280°C, the amorphous MeX shell gradually crystallized, consequently exerting strain across the formed lattice-mismatched seed/MeX heterojunctions. Over time, the shell coalesced, reshaping into a discrete MeX grain aside of the γ-Fe 2 O 3 seed (Gu et al, 2004;Kwon and Shim, 2005;Kwon et al, 2006;Selvan et al, 2007;Zanella et al, 2008;He et al, 2009). Such evolution was explained by considering that the large junction tension in the initially attained core@shell nanostructures could be greatly relieved during the annealing at high temperature, as supply of extra thermal energy promoted coalescence and dewetting of the crystallizing shell into a separate domain aside, which resulted in an obvious reduction of the interfacial area shared between the two materials.…”