Parallel Multifunctionalization of Nanoparticles: A One-Step Modular Approach for in Vivo Imaging

Bioluminescence Imaging and ICP-MS Associated with SPION as a Tool for Hematopoietic Stem and Progenitor Cells Homing and Engraftment Evaluation

Bone marrow transplantation is a treatment for a variety of hematological and non-hematological diseases. For the transplant success, it is mandatory to have a thriving engraftment of transplanted cells, which directly depends on their homing. The present study proposes an alternative method to evaluate the homing and engraftment of hematopoietic stem cells using bioluminescence imaging and inductively coupled plasma mass spectrometry (ICP-MS) associated with superparamagnetic iron oxide nanoparticles. We have identified an enriched population of hematopoietic stem cells in the bone marrow following the administration of Fluorouracil (5-FU). Lately, the cell labeling with nanoparticles displayed the greatest internalization status when treated with 30 µg Fe/mL. The quantification by ICP-MS evaluate the stem cells homing by identifying 3.95 ± 0.37 µg Fe/mL in the control and 6.61 ± 0.84 µg Fe/mL in the bone marrow of transplanted animals. In addition, 2.14 ± 0.66 mg Fe/g in the spleen of the control group and 2.17 ± 0.59 mg Fe/g in the spleen of the experimental group was also measured. Moreover, the bioluminescence imaging provided the follow up on the hematopoietic stem cells behavior by monitoring their distribution by the bioluminescence signal. Lastly, the blood count enabled the monitoring of animal hematopoietic reconstitution and ensured the transplantation effectiveness.

PET/Fluorescence Imaging: An Overview of the Chemical Strategies to Build Dual Imaging Tools

Molecular imaging is a biomedical research discipline that has quickly emerged to afford the observation, characterization, monitoring, and quantification of biomarkers and biological processes in living organism. It covers a large array of imaging techniques, each of which provides anatomical, functional, or metabolic information. Multimodality, as the combination of two or more of these techniques, has proven to be one of the best options to boost their individual properties, hence offering unprecedented tools for human health. In this review, we will focus on the combination of positron emission tomography and fluorescence imaging from the specific perspective of the chemical synthesis of dual imaging agents. Based on a detailed analysis of the literature, this review aims at giving a comprehensive overview of the chemical strategies implemented to build adequate imaging tools considering radiohalogens and radiometals as positron emitters, fluorescent dyes mostly emitting in the NIR window and all types of targeting vectors.

Targeted PET/MRI Imaging Super Probes: A Critical Review of Opportunities and Challenges

Recently, the demand for hybrid PET/MRI imaging techniques has increased significantly, which has sparked the investigation into new ways to simultaneously track multiple molecular targets and improve the localization and expression of biochemical markers. Multimodal imaging probes have recently emerged as powerful tools for improving the detection sensitivity and accuracy-both important factors in disease diagnosis and treatment; however, only a limited number of bimodal probes have been investigated in preclinical models. Herein, we briefly describe the strengths and limitations of PET and MRI modalities and highlight the need for the development of multimodal molecularly-targeted agents. We have tried to thoroughly summarize data on bimodal probes available on PubMed. Emphasis was placed on their design, safety profiles, pharmacokinetics, and clearance properties. The challenges in PET/MR probe development using a number of illustrative examples are also discussed, along with future research directions for these novel conjugates.

HAP-Multitag, a PET and Positive MRI Contrast Nanotracer for the Longitudinal Characterization of Vascular Calcifications in Atherosclerosis

Vascular microcalcifications are associated with atherosclerosis plaque instability and, therefore, to increased mortality. Because of this key role, several imaging probes have been developed for their in vivo identification. Among them, [¹⁸F]FNa is the gold standard, showing a large uptake in the whole skeleton by positron emission tomography. Here, we push the field toward the combined anatomical and functional early characterization of atherosclerosis. For this, we have developed hydroxyapatite (HAP)-multitag, a bisphosphonate-functionalized ⁶⁸Ga core-doped magnetic nanoparticle showing high affinity toward most common calcium salts present in microcalcifications, particularly HAP. We characterized this interaction in vitro and in vivo, showing a massive uptake in the atherosclerotic lesion identified by positron emission tomography (PET) and positive contrast magnetic resonance imaging (MRI). In addition, this accumulation was found to be dependent on the calcification progression, with a maximum uptake in the microcalcification stage. These results confirmed the ability of HAP-multitag to identify vascular calcifications by PET/(T₁)MRI during the vulnerable stages of the plaque progression.

Real-Time Tracking of Highly Luminescent Mesoporous Silica Particles Modified with Europium β-Diketone Chelates in Living Cells

Highly luminescent europium complexes modified mesoporous silica particles (MSP) were synthesized as an imaging probes for both in-vitro diagnostic and in-vivo cellular tracking agents. Europium β-diketone chelates (4,4,4-trifluoro-l-(2-thienyl)-l,3-butanedione) trioctylphosphine europium (III) (Eu(TTA)₃(P(Oct)₃)₃) were incorporated inside the nanocavities that existed in hierarchical MSP (Eu@MSP). The MSP and Eu@MSP on mouse bone marrow-derived macrophages (BMDMs) did not show any toxic effect. The MSP and Eu@MSP in the BMDMs were found at cytoplasm without any degradation and immunogenicity. However, both pro- and anti-inflammatory cytokines of macrophages were significantly increased when lipopolysaccharide and a high concentration (100 μg/mL) of MSP and Eu@MSP were treated simultaneously.

Radiolabeling strategies and pharmacokinetic studies for metal based nanotheranostics

Radiolabeled metal-based nanoparticles (MNPs) have drawn considerable attention in the fields of nuclear medicine and molecular imaging, drug delivery, and radiation therapy, given the fact that they can be potentially used as diagnostic imaging and/or therapeutic agents, or even as theranostic combinations. Here, we present a systematic review on recent advances in the design and synthesis of MNPs with major focuses on their radiolabeling strategies and the determinants of their in vivo pharmacokinetics, and together how their intended applications would be impacted. For clarification, we categorize all reported radiolabeling strategies for MNPs into indirect and direct approaches. While indirect labeling simply refers to the use of bifunctional chelators or prosthetic groups conjugated to MNPs for post-synthesis labeling with radionuclides, we found that many practical direct labeling methodologies have been developed to incorporate radionuclides into the MNP core without using extra reagents, including chemisorption, radiochemical doping, hadronic bombardment, encapsulation, and isotope or cation exchange. From the perspective of practical use, a few relevant examples are presented and discussed in terms of their pros and cons. We further reviewed the determinants of in vivo pharmacokinetic parameters of MNPs, including factors influencing their in vivo absorption, distribution, metabolism, and elimination, and discussed the challenges and opportunities in the development of radiolabeled MNPs for in vivo biomedical applications. Taken together, we believe the cumulative advancement summarized in this review would provide a general guidance in the field for design and synthesis of radiolabeled MNPs towards practical realization of their much desired theranostic capabilities. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > Diagnostic Nanodevices Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

nanocrystals (0 ≤ x ≤ 1): growth, size control and shell formation on β-NaCeF4:Tb core particles

is an interesting shell material for β-NaREF₄ particles of the lighter lanthanides (RE = Ce, Pr, Nd), as variation of its strontium content x allows to vary its lattice parameters and match those of the core material.

Gold nanoparticles and angiogenesis: molecular mechanisms and biomedical applications

Angiogenesis is the formation of new blood vessels from pre-existing vessels. It is a highly regulated process as determined by the interplay between pro-angiogenic and anti-angiogenic factors. Under certain conditions the balance between angiogenesis stimulators and inhibitors is altered, which results in a shift from physiological to pathological angiogenesis. Therefore, the goal of therapeutic targeting of angiogenic process is to normalize vasculature in target tissues by enhancing angiogenesis in disease conditions of reduced vascularity and blood flow, such as tissue ischemia, or alternatively to inhibit excessive and abnormal angiogenesis in disorders like cancer. Gold nanoparticles (AuNPs) are special particles that are generated by nanotechnology and composed of an inorganic core containing gold which is encircled by an organic monolayer. The ability of AuNPs to alter vasculature has captured recent attention in medical literature as potential therapeutic agents for the management of pathologic angiogenesis. This review provides an overview of the effects of AuNPs on angiogenesis and the molecular mechanisms and biomedical applications associated with their effects. In addition, the main synthesis methods, physical properties, uptake mechanisms, and toxicity of AuNPs are briefly summarized.

Production, characterization and effectiveness of cellulose acetate functionalized ZnO nanocomposite adsorbent for the removal of Se (VI) ions from aqueous media

In this study, ZnO functionalized cellulose acetate nanocomposite (ZnO/CA NC) was synthesized using a simple chemical approach found to have a high surface area of 657.34 m²/g and utilized as adsorbents for the removal of Se (VI) from aqueous solutions. Investigations on X-ray diffraction (XRD) revealed that ZnO nanocomposite has a smaller crystallite size compared to ZnO nanoparticles which facilitated for reduced agglomeration confirmed by scanning electron microscopy (SEM). The ensuing properties of ZnO/CA NC displayed high maximum adsorption capacity of 160.5 mg/g for Se (VI) ions. Inner-sphere surface complexes on ZnO/CA NC under prevailing conditions for Se (VI) were discussed using FTIR spectroscopical results. In order to evaluate the removal efficiency, the effects of adsorbent dosage, pH, and temperature were thoroughly investigated. The amount of Se (VI) ions adsorbed on ZnO/CA NC was also determined by zeta potential. The fractional removal of pollutants (Se (VI)) was done using mass transfer model. In addition, prominent adsorption capacity was also tested utilizing concurrent anions (SO₄^2-, Cl^-, and F^-) with reference to Se (VI) and cost prudent regenerability of adsorbent by NaOH solution was ascertained with anti-interference and recovery steps. ZnO/CA NC was obtained by simple chemical methodology and high surface adsorption capacities supply an encouraging technique for Se (VI) removal in water treatment applications.

Family of Bioactive Heparin-Coated Iron Oxide Nanoparticles with Positive Contrast in Magnetic Resonance Imaging for Specific Biomedical Applications

Unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH) are well-known for their anticoagulant properties. There is also currently a growing interest in using LMWH in targeted cancer therapy. In particular, several types inhibit heparanase, a key enzyme overexpressed in the tumor microenvironment that promotes angiogenesis progression and metastasis spreading. Here, we propose iron oxide nanoparticles (HEP-IONP) coated with different heparins of distinct anticoagulant/anti-heparanase activity ratios and suitable for positive contrast in magnetic resonance imaging. As a proof of concept, magnetic resonance angiography (MRA) was conducted in mice up to 3 h after intravenous administration. This new IONP-based positive contrast appropriate for clinic together with the long vascular circulating times can enable innovative theranostic applications if combined with the various bioactivities of the heparins. Indeed, we showed, using advanced in vitro tests, how HEP-IONP anticoagulant or anti-heparanase activities were maintained depending on the heparin species used for the coating. Overall, the study allowed presenting an IONP coated with a commercial LMWH (Lovenox) suggested as a theranostic translational probe for MRA diagnostic and treatment of thrombosis, and an antitumor IONP coated with a specific depolymerized heparin to be used in targeted therapy and diagnostic modalities.

Surface PEG Grafting Density Determines Magnetic Relaxation Properties of Gd-Loaded Porous Nanoparticles for MR Imaging Applications

Surface PEGylation of nanoparticles designed for biomedical applications is a common and straightforward way to stabilize the materials for in vivo administration and to increase their circulation time. This strategy becomes less trivial when MRI active porous nanomaterials are concerned as their function relies on water/proton-exchange between the pores and bulk water. Here we present a comprehensive study on the effects of PEGylation on the relaxometric properties of nanozeolite LTL (dimensions of 20 × 40 nm) ion-exchanged with paramagnetic GdIII ions. We evidence that as long as the surface grafting density of the PEG chains does not exceed the "mushroom" regime (conjugation of up to 6.2 wt % of PEG), Gd-LTL retains a remarkable longitudinal relaxivity (38 s-1 mM-1 at 7 T and 25 °C) as well as the pH-dependence of the longitudinal and transverse relaxation times. At higher PEG content, the more compact PEG layer (brush regime) limits proton/water diffusion and exchange between the interior of LTL and the bulk, with detrimental consequences on relaxivity. Furthermore, PEGylation of Gd-LTL dramatically decreases the leakage of toxic GdIII ions in biological media and in the presence of competing anions, which together with minimal cytotoxicity renders these materials promising probes for MRI applications.

AM-DMC-AMPS Multi-Functionalized Magnetic Nanoparticles for Efficient Purification of Complex Multiphase Water System

Complex multiphase waste system purification, as one of the major challenges in many industrial fields, urgently needs an efficient one-step purification method to remove several pollutants simultaneously and efficiently. Multi-functionalized magnetic nanoparticles, Fe3O4@SiO2-MPS-AM-DMC-AMPS, were facilely prepared via a one-pot in situ polymerization of three different functional monomers, AM, DMC, and AMPS, on a Fe3O4@SiO2-MPS core-shell structure. The multi-functionalized magnetic nanoparticles (MNPs) are proven to be a highly effective purification agent for oilfield wastewater, an ideal example of industrial complex multiphase waste system containing cations, anions, and organic pollutants. Excellent overall removal efficiencies for both cations, including K(+), Ca(2+), Na(+), and Mg(2+) of 80.68 %, and anions, namely Cl(-) and SO4 (2-), of 85.18 % along with oil of 97.4 % were shown. The high removal efficiencies are attributed to the effective binding of the functional groups from the selected monomers with cations, anions, and oil emulsions.

Pivotal role for skin transendothelial radio-resistant anti-inflammatory macrophages in tissue repair

Heterogeneity and functional specialization among skin-resident macrophages are incompletely understood. In this study, we describe a novel subset of murine dermal perivascular macrophages that extend protrusions across the endothelial junctions in steady-state and capture blood-borne macromolecules. Unlike other skin-resident macrophages that are reconstituted by bone marrow-derived progenitors after a genotoxic insult, these cells are replenished by an extramedullary radio-resistant and UV-sensitive Bmi1⁺ progenitor. Furthermore, they possess a distinctive anti-inflammatory transcriptional profile, which cannot be polarized under inflammatory conditions, and are involved in repair and remodeling functions for which other skin-resident macrophages appear dispensable. Based on all their properties, we define these macrophages as Skin Transendothelial Radio-resistant Anti-inflammatory Macrophages (STREAM) and postulate that their preservation is important for skin homeostasis.

DOI:http://dx.doi.org/10.7554/eLife.15251.001

The skin forms an essential barrier that defends our body from external damage. For this reason, it is important to understand the complex mechanisms involved in healing wounds and maintaining healthy skin. This could allow us to find effective treatments for skin diseases such as atopic dermatitis and psoriasis.

Immune cells called macrophages can protect the body in different ways depending on the signals they receive. Their protective roles include killing microbes that may cause disease, and helping to repair damaged tissues. Barreiro et al. have now investigated the roles of the macrophages in the skin by means of a number of complementary techniques, including a method called intravital microscopy that can image cells in a living organism.

The experiments revealed that a division of labor exists among the macrophages that reside in the skin of mice. Some macrophages help to trigger inflammatory responses in the skin. These immune cells disappear after being exposed to ionizing radiation (such as that used to treat cancer) but can be replaced via a bone marrow transplant. Other macrophages that help to repair tissues can survive being exposed to ionizing radiation but cannot resist high levels of ultraviolet light. Both types of macrophages perform unique and essential roles, and both types are necessary for maintaining healthy skin.

Barreiro et al. also discovered that the skin macrophages that help to repair tissues have the ability to move into blood vessels and take up substances from the blood. A question for future investigation is whether the macrophages perform this scavenging process to trigger a protective immune response in the nearby skin.

DOI:http://dx.doi.org/10.7554/eLife.15251.002

Characterization of multifunctional β-NaEuF4/NaGdF4 core-shell nanoparticles with narrow size distribution

The properties of β-NaEuF4/NaGdF4 core-shell nanocrystals have been thoroughly investigated. Nanoparticles with narrow size distribution and an overall diameter of ∼22 nm have been produced with either small β-NaEuF4 cores (∼3 nm diameter) or large β-NaEuF4 cores (∼18 nm diameter). The structural properties and core-shell formation are investigated by X-ray diffraction, transmission electron microscopy and electron paramagnetic resonance, respectively. Optical luminescence measurements and X-ray photoelectron spectroscopy are employed to gain information about the optical emission bands and valence states of the rare earth constituents. Magnetic characterization is performed by SQUID and X-ray magnetic circular dichroism measurements at the rare earth M(4,5) edges. The characterization of the core-shell nanoparticles by means of these complementary techniques demonstrates that partial intermixing of core and shell materials takes place, and a significant fraction of europium is present in the divalent state which has significant influence on the magnetic properties. Hence, we obtained a combination of red emitting Eu(3+) ions and paramagnetic Gd(3+) ions, which may be highly valuable for potential future applications.

Novel multifunctional nanospheres of Zn1/3Fe8/3O4@Ag: synthesis, properties and application for multi-modality tumor imaging

New multifunctional nanospheres have been designed and synthesized through a green and facile strategy, which could be readily used in multi-modality tumor imaging through near-infrared fluorescence (NIRF) imaging, magnetic resonance imaging (MRI) and computed tomography (CT) imaging.

Recent advances in superparamagnetic iron oxide nanoparticles (SPIONs) for in vitro and in vivo cancer nanotheranostics

Recently superparamagnetic iron oxide nanoparticles (SPIONs) have been extensively used in cancer therapy and diagnosis (theranostics) via magnetic targeting, magnetic resonance imaging, etc. due to their remarkable magnetic properties, chemical stability, and biocompatibility. However, the magnetic properties of SPIONs are influenced by various physicochemical and synthesis parameters. So, this review mainly focuses on the influence of spin canting effects, introduced by the variations in size, shape, and organic/inorganic surface coatings, on the magnetic properties of SPIONs. This review also describes the several predominant chemical synthesis procedures and role of the synthesis parameters for monitoring the size, shape, crystallinity and composition of the SPIONs. Moreover, this review discusses about the latest developments of the inorganic materials and organic polymers for encapsulation of the SPIONs. Finally, the most recent advancements of the SPIONs and their nanopackages in combination with other imaging/therapeutic agents have been comprehensively discussed for their effective usage as in vitro and in vivo theranostic agents in cancer treatments.

Potential Use of Biological Proteins for Liver Failure Therapy

Biological proteins have unlimited potential for use as pharmaceutical products due to their various biological activities, which include non-toxicity, biocompatibility, and biodegradability. Recent scientific advances allow for the development of novel innovative protein-based products that draw on the quality of their innate biological activities. Some of them hold promising potential for novel therapeutic agents/devices for addressing hepatic diseases such as hepatitis, fibrosis, and hepatocarcinomas. This review attempts to provide an overview of the development of protein-based products that take advantage of their biological activity for medication, and discusses possibilities for the therapeutic potential of protein-based products produced through different approaches to specifically target the liver (or hepatic cells: hepatocytes, hepatic stellate cells, liver sinusoidal endothelial cells, and Kupffer cells) in the treatment of hepatic diseases.

NaGdF4:Yb(3+)/Er(3+)@NaGdF4:Nd(3+)@Sodium-Gluconate: Multifunctional and Biocompatible Ultrasmall Core-Shell Nanohybrids for UCL/MR/CT Multimodal Imaging

Multimodal bioimaging nanoparticles by integrating diverse imaging ingredients into one system, represent a class of emerging advanced materials that provide more comprehensive and accurate clinical diagnostics than conventional contrast agents. Here monodisperse and biocompatible core-shell nanoparticles, NaGdF4: Yb(3+)/Er(3+)@NaGdF4:Nd@sodium-gluconate (termed as GNa-Er@Nd), with about 26 nm in diameter were successfully prepared by a facile two step reactions in high boiling solvents, and followed a ligand exchange process with sodium gluconate. The resulting GNa-Er@Nd nanoparticles were well characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), and zeta potentials. These nanohybrids present brightly dual-wavelength excited upconversion luminescence (UCL) under both 980 and 793 nm laser because of the synergistic effect of Yb(3+)/Er(3+) and Nd(3+). They also exhibited excellent relaxivity parameters (r1) in magnetic resonance imaging (MRI) and Hounsfield units (HU) in X-ray computed tomography (CT) that are comparable to the clinical contrast agents. Therefore, these small and monodisperse nanoparticles provide options to construct a unique platform for potential multimodal UCL/CT/MRI imaging simultaneously.