Highly cohesive dual nanoassemblies for complementary multiscale bioimaging

Abstract

International audienceInnovative nanostructures made of a high payload of fluorophores and superparamagnetic nanoparticles (NPs) have simply been fabricated upon self-assembling in a two-step process. The resulting hybrid supraparticles displayed a dense shell of iron oxide nanoparticles tightly attached through an appropriate polyelectrolyte to a highly emissive non-doped nanocore made of more than 10 5 small organic molecules. Cooperative magnetic dipole interactions arose due to the closely packed magnetic NPs at the nanoarchitecture surface, causing enhanced NMR transverse relaxivity. Large in vivo MRI T 2 contrast was thus obtained with unusually diluted solutions after intravenous injection in small rodents. Two-photon excited fluorescence imaging could be performed, achieving unprecedented location resolution for agents combining both magnetic nanoparticles and fluorescence properties. Finally, TEM imaging of the sectioned mouse tissue succeeded in isolating the core–shell structures, which represents the first image of intact complex magnetic and fluorescent nanoassemblies upon in vivo injection. Such highly cohesive dual nanoarchitectures should open great horizons toward the assessment with high spatial resolution of the drug or labeled stem cell biodistribution

PEGylated Anionic Magnetofluorescent Nanoassemblies: Impact of Their Interface Structure on Magnetic Resonance Imaging Contrast and Cellular Uptake

“…18 Thus, PAA has currently appeared as a very attractive biocompatible stabilizing ligand as it displays strong affinity for iron oxide, [19][20] little toxicity 21 and multiple anchoring points, limiting its detachment from the iron oxide surface, even after in vivo injection. 22 More recently, poly(phosphonic acid) (PPA) known for its even larger association to iron, was also showed to form very strong stabilizing shell around SPIONs. [23][24] While most of studies have largely investigated the impact of the diameter of SPIONs and magnetic nanoassemblies on MRI contrast and cellular uptake, 5,25 the effects of the polymer shell architecture are much more rarely been scrutinized.…”

Pro‐osteoclastic in vitro effect of Polyethylene‐like nanoparticles: Involvement in the pathogenesis of implant aseptic loosening

“…17 Finally, these nanoparticles are detectable and biocompatible by presenting fluorophores akin to those used in fluorescent and magnetofluorescent nanoparticles exploited for in cellulo 11 and in vitro MRI imaging. 12 In those cases, cell viability assays showed no detectable cytotoxicity, confirming the biocompatibility of fluorescent organic nanoparticles while strong emissive signal could be observed inside the cells after internalization. Moreover, we established a culture system of macrophages and osteoclasts exposed to nanoparticles in suspension overcoming the technical limitations reported for classical bi-dimensional culture systems challenged with polyethylene particles.…”

“…The recognition of DAMPs by TLRs is an crucial step in the classical activation of naïve macrophages to the pro‐inflammatory phenotype . Finally, these nanoparticles are detectable and biocompatible by presenting fluorophores akin to those used in fluorescent and magnetofluorescent nanoparticles exploited for in cellulo and in vitro MRI imaging . In those cases, cell viability assays showed no detectable cytotoxicity, confirming the biocompatibility of fluorescent organic nanoparticles while strong emissive signal could be observed inside the cells after internalization.…”

“…Macrophage cell culture 1.5 3 10 6 human blood-derived CD14 1 monocytes were seeded in six-well plate and cultured for 3 days in 2 ml of minimum essential medium alpha (MEM-a, Lonza, Belgium) supplemented with 10% foetal bovine serum (FBS, Ozyme, France), 1% of antibiotics and supplemented with 25 ng/ mL of human macrophage colony stimulating factor (hM-CSF, R&D systems, Abingdon, UK) (macrophage growth media). Then, adherent CD14 1 cells were cultured in macrophage media as naive macrophages and incubated with three different ratios of FPN per cell during 1,4,8,12,24,48, and 72 h. The three ratios of FPN were theoretically calculated from the stock solution concentration (4 3 10 10 FPN/mL) and diluting in culture media accordingly. They are 2 3 10 3 FPN per cell (baseline equivalent with 2 3 10 9 FPN/mL), 4 3 10 3 FPN per cell (equivalent with 4 3 10 9 FPN/mL) and 8 310 3 FPN per cell (equivalent with 8 3 10 9 FPN/mL).…”

Luminophore and Magnetic Multicore Nanoassemblies for Dual-Mode MRI and Fluorescence Imaging

“…The use of magneto-fluorescent nanoassemblies provides generally biodegradable systems that advantageously avoid bioaccumulation. In this context, several molecular matrices are envisaged composed of polymers [151][152][153][154][155][156][157][158][159], lipids [160][161][162][163], PDots [164][165][166][167] or organic molecule [168][169][170][171][172] ( Figure 6). In this type of organization we will distinguish the assemblies with inert matrices of those composed of active units.…”