Amine-surface-modified superparamagnetic iron oxide nanoparticles interfere with differentiation of human mesenchymal stem cells

Fighting age-related orthopedic diseases: focusing on ferroptosis

Ferroptosis, a unique type of cell death, is characterized by iron-dependent accumulation and lipid peroxidation. It is closely related to multiple biological processes, including iron metabolism, polyunsaturated fatty acid metabolism, and the biosynthesis of compounds with antioxidant activities, including glutathione. In the past 10 years, increasing evidence has indicated a potentially strong relationship between ferroptosis and the onset and progression of age-related orthopedic diseases, such as osteoporosis and osteoarthritis. Therefore, in-depth knowledge of the regulatory mechanisms of ferroptosis in age-related orthopedic diseases may help improve disease treatment and prevention. This review provides an overview of recent research on ferroptosis and its influences on bone and cartilage homeostasis. It begins with a brief overview of systemic iron metabolism and ferroptosis, particularly the potential mechanisms of ferroptosis. It presents a discussion on the role of ferroptosis in age-related orthopedic diseases, including promotion of bone loss and cartilage degradation and the inhibition of osteogenesis. Finally, it focuses on the future of targeting ferroptosis to treat age-related orthopedic diseases with the intention of inspiring further clinical research and the development of therapeutic strategies.

Advanced Hydrogel systems for mandibular reconstruction

Mandibular defect becomes a prevalent maxillofacial disease resulting in mandibular dysfunctions and huge psychological burdens to the patients. Considering the routine presence of oral contaminations and aesthetic restoration of facial structures, the current clinical treatments are however limited, incapable to reconstruct the structural integrity and regeneration, spurring the need for cost-effective mandibular tissue engineering. Hydrogel systems possess great merit for mandibular reconstruction with precise involvement of cells and bioactive factors. In this review, current clinical treatments and distinct mode(s) of mandible formation and pathological resorption are summarized, followed by a review of hydrogel-related mandibular tissue engineering, and an update on the advanced fabrication of hydrogels with improved mechanical property, antibacterial ability, injectable form, and 3D bioprinted hydrogel constructs. The exploration of advanced hydrogel systems will lay down a solid foundation for a bright future with more biocompatible, effective, and personalized treatment in mandibular reconstruction.

Synthesis and Characterization of Supermagnetic Nanocomposites Coated with Pluronic F127 as a Contrast Agent for Biomedical Applications

Nanomedicine has garnered significant interest owing to advances in drug delivery, effectively demonstrated in the treatment of certain diseases. Here, smart supermagnetic nanocomposites based on iron oxide nanoparticles (MNPs) coated with Pluronic F127 (F127) were developed for the delivery of doxorubicin (DOX) to tumor tissues. The XRD patterns for all samples revealed peaks consistent with Fe3O4, as shown by their indices (220), (311), (400), (422), (511), and (440), demonstrating that the structure of Fe3O4 did not change after the coating process. After loading with DOX, the as-prepared smart nanocomposites demonstrated drug-loading efficiency and drug-loading capacity percentages of 45 ± 0.10 and 17 ± 0.58% for MNP-F127-2-DOX and 65 ± 0.12 and 13 ± 0.79% for MNP-F127-3-DOX, respectively. Moreover, a better DOX release rate was observed under acidic conditions, which may be credited to the pH sensitivity of the polymer. In vitro analysis demonstrated the survival rate of approximately 90% in HepG2 cells treated with PBS and MNP-F127-3 nanocomposites. Furthermore, after treatment with MNP-F127-3-DOX, the survival rate decreased, confirming cellular inhibition. Hence, the synthesized smart nanocomposites showed great promise for drug delivery in liver cancer treatment, overcoming the limitations of traditional therapies.

Efficient Liposome Loading onto Surface of Mesenchymal Stem Cells via Electrostatic Interactions for Tumor-Targeted Drug Delivery

Mesenchymal stem cells (MSCs) have a tumor-homing capacity; therefore, MSCs are a promising drug delivery carrier for cancer therapy. To maintain the viability and activity of MSCs, anti-cancer drugs are preferably loaded on the surface of MSCs, rather than directly introduced into MSCs. In this study, we attempted to load liposomes on the surface of MSCs by using the magnetic anionic liposome/atelocollagen complexes that we previously developed and assessed the characters of liposome-loaded MSCs as drug carriers. We observed that large-sized magnetic anionic liposome/atelocollagen complexes were abundantly associated with MSCs via electrostatic interactions under a magnetic field, and its cellular internalization was lower than that of the small-sized complexes. Moreover, the complexes with higher atelocollagen concentrations showed lower cellular internalization than the complexes with lower atelocollagen concentrations. Based on these results, we succeeded in the efficient loading of liposomes on the surface of MSCs by using large-sized magnetic anionic liposomes complexed with a high concentration of atelocollagen. The constructed liposome-loaded MSCs showed a comparable proliferation rate and differentiation potential to non-loaded MSCs. Furthermore, the liposome-loaded MSCs efficiently adhered to vascular endothelial cells and migrated toward the conditioned medium from cancer cells in vitro and solid tumor tissue in vivo. These findings suggest that liposome-loaded MSCs could serve as an efficient cell-based drug carrier for tumor-targeted delivery.

In Vivo Cellular Magnetic Imaging: Labeled vs. Unlabeled Cells

Superparamagnetic iron oxide (SPIO)-labeling of cells has been applied for magnetic resonance imaging (MRI) cell tracking for over 30 years, having resulted in a dozen or so clinical trials. SPIO nanoparticles are biodegradable and can be broken down into elemental iron, and hence the tolerance of cells to magnetic labeling has been overall high. Over the years, however, single reports have accumulated demonstrating that the proliferation, migration, adhesion and differentiation of magnetically labeled cells may differ from unlabeled cells, with inhibition of chondrocytic differentiation of labeled human mesenchymal stem cells (hMSCs) as a notable example. This historical perspective provides an overview of some of the drawbacks that can be encountered with magnetic labeling. Now that magnetic particle imaging (MPI) cell tracking is emerging as a new in vivo cellular imaging modality, there has been a renaissance in the formulation of SPIO nanoparticles this time optimized for MPI. Lessons learned from the occasional past pitfalls encountered with SPIO-labeling of cells for MRI may expedite possible future clinical translation of (combined) MRI/MPI cell tracking.

Biological Impact of γ-Fe2O3 Magnetic Nanoparticles Obtained by Laser Target Evaporation: Focus on Magnetic Biosensor Applications

The biological activity of γ-Fe2O3 magnetic nanoparticles (MNPs), obtained by the laser target evaporation technique, was studied, with a focus on their possible use in biosensor applications. The biological effect of the MNPs was investigated in vitro on the primary cultures of human dermal fibroblasts. The effects of the MNPs contained in culture medium or MNPs already uptaken by cells were evaluated for the cases of the fibroblast’s proliferation and secretion of cytokines and collagen. For the tests related to the contribution of the constant magnetic field to the biological activity of MNPs, a magnetic system for the creation of the external magnetic field (having no commercial analogues) was designed, calibrated, and used. It was adapted to the size of standard 24-well cell culture plates. At low concentrations of MNPs, uptake by fibroblasts had stimulated their proliferation. Extracellular MNPs stimulated the release of pro-inflammatory cytokines (Interleukin-6 (IL-6) and Interleukin-8 (IL-8) or chemokine (C-X-C motif) ligand 8 (CXCL8)) in a concentration-dependent manner. However, the presence of MNPs did not increase the collagen secretion. The exposure to the uniform constant magnetic field (H ≈ 630 or 320 Oe), oriented in the plane of the well, did not cause considerable changes in fibroblasts proliferation and secretion, regardless of presence of MNPs. Statistically significant differences were detected only in the levels of IL-8/CXCL8 release.

Nanotechnology-Assisted Cell Tracking

The usefulness of nanoparticles (NPs) in the diagnostic and/or therapeutic sector is derived from their aptitude for navigating intra- and extracellular barriers successfully and to be spatiotemporally targeted. In this context, the optimization of NP delivery platforms is technologically related to the exploitation of the mechanisms involved in the NP–cell interaction. This review provides a detailed overview of the available technologies focusing on cell–NP interaction/detection by describing their applications in the fields of cancer and regenerative medicine. Specifically, a literature survey has been performed to analyze the key nanocarrier-impacting elements, such as NP typology and functionalization, the ability to tune cell interaction mechanisms under in vitro and in vivo conditions by framing, and at the same time, the imaging devices supporting NP delivery assessment, and consideration of their specificity and sensitivity. Although the large amount of literature information on the designs and applications of cell membrane-coated NPs has reached the extent at which it could be considered a mature branch of nanomedicine ready to be translated to the clinic, the technology applied to the biomimetic functionalization strategy of the design of NPs for directing cell labelling and intracellular retention appears less advanced. These approaches, if properly scaled up, will present diverse biomedical applications and make a positive impact on human health.

Magnetic Nanoparticles in Bone Tissue Engineering

Large bone defects with limited intrinsic regenerative potential represent a major surgical challenge and are associated with a high socio-economic burden and severe reduction in the quality of life. Tissue engineering approaches offer the possibility to induce new functional bone regeneration, with the biomimetic scaffold serving as a bridge to create a microenvironment that enables a regenerative niche at the site of damage. Magnetic nanoparticles have emerged as a potential tool in bone tissue engineering that leverages the inherent magnetism of magnetic nano particles in cellular microenvironments providing direction in enhancing the osteoinductive, osteoconductive and angiogenic properties in the design of scaffolds. There are conflicting opinions and reports on the role of MNPs on these scaffolds, such as the true role of magnetism, the application of external magnetic fields in combination with MNPs, remote delivery of biomechanical stimuli in-vivo and magnetically controlled cell retention or bioactive agent delivery in promoting osteogenesis and angiogenesis. In this review, we focus on the role of magnetic nanoparticles for bone-tissue-engineering applications in both disease modelling and treatment of injuries and disease. We highlight the materials-design pathway from implementation strategy through the selection of materials and fabrication methods to evaluation. We discuss the advances in this field and unmet needs, current challenges in the development of ideal materials for bone-tissue regeneration and emerging strategies in the field.

Superparamagnetic Iron Oxide Nanoparticles: Cytotoxicity, Metabolism, and Cellular Behavior in Biomedicine Applications

Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely investigated and applied in the field of biomedicine due to their excellent superparamagnetic properties and reliable traceability. However, with the optimization of core composition, shell types and transfection agents, the cytotoxicity and metabolism of different SPIONs have great differences, and the labeled cells also show different cellular behaviors. Therefore, a holistic review of the construction and application of SPIONs is desired. This review focuses the advances of SPIONs in the field of biomedicine in recent years. After summarizing the toxicity of different SPIONs, the uptake, distribution and metabolism of SPIONs in vitro were discussed. Then, the regulation of labeled-cells behavior is outlined. Furthermore, the major challenges in the optimization process of SPIONs and insights on its future developments are proposed.

Shaping the bone through iron and iron-related proteins

Well-controlled iron levels are indispensable for health. Iron deficiency is the most common cause of anemia, whereas iron overload, either hereditary or secondary due to disorders of ineffective erythropoiesis, causes widespread organ failure. Bone is particularly sensitive to fluctuations in systemic iron levels as both iron deficiency and overload are associated with low bone mineral density and fragility. Recent studies have shown that not only iron itself, but also iron-regulatory proteins that are mutated in hereditary hemochromatosis can control bone mass. This review will summarize the current knowledge on the effects of iron on bone homeostasis and bone cell activities, and on the role of proteins that regulate iron homeostasis, i.e. hemochromatosis proteins and proteins of the bone morphogenetic protein pathway, on bone remodeling. As disorders of iron homeostasis are closely linked to bone fragility, deeper insights into common regulatory mechanisms may provide new opportunities to concurrently treat disorders affecting iron homeostasis and bone.

Chitosan, Polyethylene Glycol and Polyvinyl Alcohol Modified MgFe2O4 Ferrite Magnetic Nanoparticles in Doxorubicin Delivery: A Comparative Study In Vitro

Cancer-based magnetic theranostics has gained significant interest in recent years and can contribute as an influential archetype in the effective treatment of cancer. Owing to their excellent biocompatibility, minute sizes and reactive functional surface groups, magnetic nanoparticles (MNPs) are being explored as potential drug delivery systems. In this study, MgFe₂O₄ ferrite MNPs were evaluated for their potential to augment the delivery of the anticancer drug doxorubicin (DOX). These MNPs were successfully synthesized by the glycol-thermal method and functionalized with the polymers; chitosan (CHI), polyvinyl alcohol (PVA) and polyethylene glycol (PEG), respectively, as confirmed by Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction (XRD) confirmed the formation of the single-phase cubic spinel structures while vibrating sample magnetometer (VSM) analysis confirmed the superparamagnetic properties of all MNPs. Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) revealed small, compact structures with good colloidal stability. CHI-MNPs had the highest DOX encapsulation (84.28%), with the PVA-MNPs recording the lowest encapsulation efficiency (59.49%). The 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) cytotoxicity assays conducted in the human embryonic kidney (HEK293), colorectal adenocarcinoma (Caco-2), and breast adenocarcinoma (SKBR-3) cell lines showed that all the drug-free polymerized MNPs promoted cell survival, while the DOX loaded MNPs significantly reduced cell viability in a dose-dependent manner. The DOX-CHI-MNPs possessed superior anticancer activity (<40% cell viability), with approximately 85.86% of the drug released after 72 h in a pH-responsive manner. These MNPs have shown good potential in enhancing drug delivery, thus warranting further optimizations and investigations.

Superparamagnetic Iron Oxide Particles (VSOPs) Show Genotoxic Effects but No Functional Impact on Human Adipose Tissue-Derived Stromal Cells (ASCs)

Adipose tissue-derived stromal cells (ASCs) represent a capable source for cell-based therapeutic approaches. For monitoring a cell-based application in vivo, magnetic resonance imaging (MRI) of cells labeled with iron oxide particles is a common method. It is the aim of the present study to analyze potential DNA damage, cytotoxicity and impairment of functional properties of human (h)ASCs after labeling with citrate-coated very small superparamagnetic iron oxide particles (VSOPs). Cytotoxic as well as genotoxic effects of the labeling procedure were measured in labeled and unlabeled hASCs using the MTT assay, comet assay and chromosomal aberration test. Trilineage differentiation was performed to evaluate an impairment of the differentiation potential due to the particles. Proliferation as well as migration capability were analyzed after the labeling procedure. Furthermore, the labeling of the hASCs was confirmed by Prussian blue staining, transmission electron microscopy (TEM) and high-resolution MRI. Below the concentration of 0.6 mM, which was used for the procedure, no evidence of genotoxic effects was found. At 0.6 mM, 1 mM as well as 1.5 mM, an increase in the number of chromosomal aberrations was determined. Cytotoxic effects were not observed at any concentration. Proliferation, migration capability and differentiation potential were also not affected by the procedure. Labeling with VSOPs is a useful labeling method for hASCs that does not affect their proliferation, migration and differentiation potential. Despite the absence of cytotoxicity, however, indications of genotoxic effects have been demonstrated.

New Insights into Biocompatible Iron Oxide Nanoparticles: A Potential Booster of Gene Delivery to Stem Cells

Gene delivery to stem cells is a critical issue of stem cells-based therapies, still facing ongoing challenges regarding efficiency and safety. Recent advances in the controlled synthesis of biocompatible magnetic iron oxide nanoparticles (IONPs) have provided a powerful nanotool for assisting gene delivery to stem cells. However, this field is still at an early stage, with well-designed and scalable IONPs synthesis highly desired. Furthermore, the potential risks or bioeffects of IONPs on stem cells are not completely figured out. Therefore, in this review, the updated researches focused on the gene delivery to stem cells using various designed IONPs are highlighted. Additionally, the impacts of the physicochemical properties of IONPs, as well as the magnetofection systems on the gene delivery performance and biocompatibility are summarized. Finally, challenges attributed to the potential impacts of IONPs on the biologic behaviors of stem cells and the large-scale productions of uniform IONPs are emphasized. The principles and challenges summarized in this review provide a general guidance for the rational design of IONPs-assisted gene delivery to stem cells.

Synthesis and toxicity assessment of Fe3O4 NPs grafted by ∼ NH2-Schiff base as anticancer drug: modeling and proposed molecular mechanism through docking and molecular dynamic simulation

Superparamagnetic iron oxide nanoparticles have been synthesized using chain length of (3-aminopropyl) triethoxysilane for cancer therapy. First, we have developed a layer by layer functionalized with grafting 2,4-toluene diisocyanate as a bi-functional covalent linker onto a nano-Fe₃O₄ support. Then, they were characterized by Fourier transform infrared, X-ray powder diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and VSM techniques. Finally, all nanoparticles with positive or negative surface charges were tested against K562 (myelogenous leukemia cancer) cell lines to demonstrate their therapeutic efficacy by MTT assay test. We found that the higher toxicity of Fe₃O₄@SiO₂@APTS ∼ Schiff base-Cu(II) (IC₅₀: 1000 μg/mL) is due to their stronger in situ degradation, with larger intracellular release of iron ions, as compared to surface passivated NPs. For first time, the molecular dynamic simulations of all compounds were carried out afterwards optimizing using MM+, Semi-empirical (AM1) and Ab-initio (STO-3G), Forcite Gemo Opt, Forcite Dynamics, Forcite Energy and CASTEP in Materials studio 2017. The energy (eV), space group, lattice parameters (Å), unit cell parameters (Å), and electron density of the predicted structures were taken from the CASTEP module of Materials Studio. The docking methods were used to predict the DNA binding affinity, ribonucleotide reductase, and topoisomerase II.

Assessment of proliferation, migration and differentiation potentials of bone marrow mesenchymal stem cells labeling with silica-coated and amine-modified superparamagnetic iron oxide nanoparticles

Superparamagnetic iron oxide nanoparticles have been widely used for cell labeling in preclinical and clinical studies, to improve labeling efficiency, particle conjugation and surface modifications are developed, but some modified SPIONs exert side-effect on physiological activity of cells, which cannot be served as ideal cell tracker. In this study, amine-modified silica-coated SPIO (SPIO@SiO₂-NH₂, SPIO@S-N) nanoparticles were used to label bone marrow derived mesenchymal stem cells (BM-MSCs), then the stem cell potentials were evaluated. It was found BM-MSCs could be efficiently labeled by SPIO@S-N nanoparticles. After labeling, the BM-MSCs viability kept well and the migration ability increased, but the osteogenesis and adipogenesis potentials were not impaired. In steroid associated osteonecrosis (SAON) bone defect model, stem cell implantation was performed by injection of SPIO@S-N labeled BM-MSCs into marrow cavity locally, it was found the SPIO positive cells homed to the periphery of defect region in control group, but were recruited to the defect region in poly lactic-coglycolic acid/tricalcium phosphate (PLGA/TCP) scaffold implantation group. In conclusion, SPIO@S-N nanoparticles promoted migration while retained proliferation and differentiation ability of BM-MSCs, implying this kind of nanoparticles could be served not only an ideal tracking marker but also an accelerator for stem cell homing during tissue repair.

Synthesis, Characterization, Biomedical Application, Molecular Dynamic Simulation and Molecular Docking of Schiff Base Complex of Cu(II) Supported on Fe3O4/SiO2/APTS

INTRODUCTION

Over the past several years, nano-based therapeutics were an effective cancer drug candidate in order to overcome the persistence of deadliest diseases and prevalence of multiple drug resistance (MDR).

METHODS

The main objective of our program was to design organosilane-modified Fe3O4/SiO2/APTS(~NH2) core magnetic nanocomposites with functionalized copper-Schiff base complex through the use of (3-aminopropyl)triethoxysilane linker as chemotherapeutics to cancer cells. The nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), TEM, and vibrating sample magnetometer (VSM) techniques. All analyses corroborated the successful synthesis of the nanoparticles. In the second step, all compounds of magnetic nanoparticles were validated as antitumor drugs through the conventional MTT assay against K562 (myelogenous leukemia cancer) and apoptosis study by Annexin V/PI and AO/EB. The molecular dynamic simulations of nanoparticles were further carried out; afterwards, the optimization was performed using MM+, semi-empirical (AM1) and Ab Initio (STO-3G), ForciteGemo Opt, Forcite Dynamics, Forcite Energy and CASTEP in Materials studio 2017.

RESULTS

The results showed that the anti-cancer activity was barely reduced after modifying the surface of the Fe3O4/SiO2/APTS nanoparticles with 2-hydroxy-3-methoxybenzaldehyde as Schiff base and then Cu(II) complex. The apoptosis study by Annexin V/PI and AO/EB stained cell nuclei was performed that apoptosis percentage of the nanoparticles increased upon increasing the thickness of Fe3O4 shell on the magnetite core. The docking studies of the synthesized compounds were conducted towards the DNA and Topoisomerase II via AutoDock 1.5.6 (The Scripps Research Institute, La Jolla, CA, USA).

CONCLUSION

Results of biology activities and computational modeling demonstrate that nanoparticles were targeted drug delivery system in cancer treatment.

Engineered iron oxide nanoparticles to improve regenerative effects of mesenchymal stem cells

Abstract

Mesenchymal stem cells (MSCs) based therapies are a major field of regenerative medicine. However, the success of MSC therapy relies on the efficiency of its delivery and retention, differentiation, and secreting paracrine factors at the target sites. Recent studies show that superparamagnetic iron oxide nanoparticles (SPIONs) modulate the regenerative effects of MSCs. After interacting with the cell membrane of MSCs, SPIONs can enter the cells via the endocytic pathway. The physicochemical properties of nanoparticles, including size, surface charge (zeta-potential), and surface ligand, influence their interactions with MSC, such as cellular uptake, cytotoxicity, homing factors, and regenerative related factors (VEGF, TGF-β1). Therefore, in-depth knowledge of the physicochemical properties of SPIONs might be a promising lead in regenerative and anti-inflammation research using SPIONs mediated MSCs. In this review, recent research on SPIONs with MSCs and the various designs of SPIONs are examined and summarized.

Graphic abstract

A graphical abstract describes important parameters in the design of superparamagnetic iron oxide nanoparticles, affecting mesenchymal stem cells. These physicochemical properties are closely related to the mesenchymal stem cells to achieve improved cellular responses such as homing factors and cell uptake.

Targeting strategies for superparamagnetic iron oxide nanoparticles in cancer therapy

Among various nanoparticles, superparamagnetic iron oxide nanoparticles (SPIONs) have been increasingly studied for their excellent superparamagnetism, magnetic heating properties, and enhanced magnetic resonance imaging (MRI). The conjugation of SPIONs with drugs to obtain delivery nanosystems has several advantages including magnetic targeted functionalization, in vivo imaging, magnetic thermotherapy, and combined delivery of anticancer agents. To further increase the targeting efficiency of drugs through a delivery nanosystem based on SPIONs, additional targeting moieties including transferrin, antibodies, aptamers, hyaluronic acid, folate, and targeting peptides are coated onto the surface of SPIONs. Therefore, this review summarizes the latest progresses in the conjugation of targeting molecules and drug delivery nanosystems based on SPIONs, especially focusing on their performances to develop efficient targeted drug delivery systems for tumor therapy. STATEMENT OF SIGNIFICANCE: Some magnetic nanoparticle-based nanocarriers loaded with drugs were evaluated in patients and did not produce convincing results, leading to termination of clinical development in phase II/III. An alternative strategy for drug delivery systems based on SPIONs is the conjugation of these systems with targeting segments such as transferrin, antibodies, aptamers, hyaluronic acid, folate, and targeting peptides. These targeting moieties can be recognized by specific integrin/receptors that are overexpressed specifically on the tumor cell surface, resulting in minimizing dosage and reducing off-target effects. This review focuses on magnetic nanoparticle-based nonviral drug delivery systems with targeting moieties to deliver anticancer drugs, with an aim to provide suggestions on the development of SPIONs through discussion.

Labeling of human mesenchymal stem cells with different classes of vital stains: robustness and toxicity

Background

Mesenchymal stem cell (MSC) transplantation has been explored as a new clinical approach to repair injured tissues. However, in order to evaluate the therapeutic activity of MSC, cell tracking techniques are required to determine the fate of transplanted cells in both preclinical and clinical studies. In these aspects, different vital stains offer the potential for labeling and monitoring of grafted cells in vivo. It is desirable to have tracking agents which have long-term stability, are not toxic to the cells, and do not affect cell function.

Methods

Here, we selected three different labels: CellTracker™ Green CMFDA, eGFP-mRNA (genetic pre-tag), and Molday ION Rhodamine B™ (nanoparticle-based fluorescent and magnetic label) and performed extensive analysis of their influence on in vitro expansion of human bone marrow-derived mesenchymal stem cells (hBM-MSCs), as well as potential of affecting therapeutic activity and the impact on the durability of staining.

Results

Our study showed that basic hBM-MSC characteristics and functions might be affected by labeling. We observed strong alterations of metabolic activity and morphology after eGFP and CellTracker™ Green CMFDA hBM-MSC staining. Molday ION Rhodamine B™ labeling revealed superior properties relatively to other vital stains. The relative expression level of most of the investigated growth factors remained stable after cell labeling, but we have observed some changes in the case of EGF, GDNF, HGF, and IGF gene expression.

Conclusions

Taken together, we suggest performing similar to ours extensive analysis prior to using any cell label to tag MSC in experiments, as it can thoroughly bias results.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1296-8) contains supplementary material, which is available to authorized users.

A brief review of cytotoxicity of nanoparticles on mesenchymal stem cells in regenerative medicine

Multipotent mesenchymal stem cells have shown great promise for application in regenerative medicine owing to their particular therapeutic effects, such as significant self-renewability, low immunogenicity, and ability to differentiate into a variety of specialized cells. However, there remain certain complicated and unavoidable problems that limit their further development and application. One of the challenges is to noninvasively monitor the delivery and biodistribution of transplanted stem cells during treatment without relying on behavioral endpoints or tissue histology, and it is important to explore the potential mechanisms to clarify how stem cells work in vivo. To solve these problems, various nanoparticles (NPs) and their corresponding imaging methods have been developed recently and have made great progress. In this review, we mainly discuss NPs used to label stem cells and their toxic effects on the latter, the imaging techniques to detect such NPs, and the current existing challenges in this field.

Adverse Effects of Fine-Particle Exposure on Joints and Their Surrounding Cells and Microenvironment

Current understanding of the health risks and adverse effects upon exposure to fine particles is premised on the direct association of particles with target organs, particularly the lung; however, fine-particle exposure has also been found to have detrimental effects on sealed cavities distant to the portal-of-entry, such as joints. Moreover, the fundamental toxicological issues have been ascribed to the direct toxic mechanisms, in particular, oxidative stress and proinflammatory responses, without exploring the indirect mechanisms, such as compensated, adaptive, and secondary effects. In this Review, we recapitulate the current findings regarding the detrimental effects of fine-particle exposure on joints, the surrounding cells, and microenvironment, as well as their deteriorating impact on the progression of arthritis. We also elaborate the likely molecular mechanisms underlying the particle-induced detrimental influence on joints, not limited to direct toxicity, but also considering the other indirect mechanisms. Because of the similarities between fine air particles and engineered nanomaterials, we compare the toxicities of engineered nanomaterials to those of fine air particles. Arthritis and joint injuries are prevalent, particularly in the elderly population. Considering the severity of global exposure to fine particles and limited studies assessing the detrimental effects of fine-particle exposure on joints and arthritis, this Review aims to appeal to a broad interest and to promote more research efforts in this field.

Biosynthesis of magnetic nanoparticles from nano-degradation products revealed in human stem cells

While magnetic nanoparticles offer exciting possibilities for stem cell imaging or tissue bioengineering, their long-term intracellular fate remains to be fully documented. Besides, it appears that magnetic nanoparticles can occur naturally in human cells, but their origin and potentially endogenous synthesis still need further understanding. In an effort to explore the life cycle of magnetic nanoparticles, we investigated their transformations upon internalization in mesenchymal stem cells and as a function of the cells' differentiation status (undifferentiated, or undergoing adipogenesis, osteogenesis, and chondrogenesis). Using magnetism as a fingerprint of the transformation process, we evidenced an important degradation of the nanoparticles during chondrogenesis. For the other pathways, stem cells were remarkably "remagnetized" after degradation of nanoparticles. This remagnetization phenomenon is the direct demonstration of a possible neosynthesis of magnetic nanoparticles in cellulo and could lay some foundation to understand the presence of magnetic crystals in human cells. The neosynthesis was shown to take place within the endosomes and to involve the H-subunit of ferritin. Moreover, it appeared to be the key process to avoid long-term cytotoxicity (impact on differentiation) related to high doses of magnetic nanoparticles within stem cells.

Influence of Iron on Bone Homeostasis

Bone homeostasis is a complex process, wherein osteoclasts resorb bone and osteoblasts produce new bone tissue. For the maintenance of skeletal integrity, this sequence has to be tightly regulated and orchestrated. Iron overload as well as iron deficiency disrupt the delicate balance between bone destruction and production, via influencing osteoclast and osteoblast differentiation as well as activity. Iron overload as well as iron deficiency are accompanied by weakened bones, suggesting that balanced bone homeostasis requires optimal-not too low, not too high-iron levels. The goal of this review is to summarize our current knowledge about how imbalanced iron influence skeletal health. Better understanding of this complex process may help the development of novel therapeutic approaches to deal with the pathologic effects of altered iron levels on bone.

Uptake and Intracellular Fate of Engineered Nanoparticles in Mammalian Cells: Capabilities and Limitations of Transmission Electron Microscopy-Polymer-Based Nanoparticles

In order to elucidate mechanisms of nanoparticle (NP)-cell interactions, a detailed knowledge about membrane-particle interactions, intracellular distributions, and nucleus penetration capabilities, etc. becomes indispensable. The utilization of NPs as additives in many consumer products, as well as the increasing interest of tailor-made nanoobjects as novel therapeutic and diagnostic platforms, makes it essential to gain deeper insights about their biological effects. Transmission electron microscopy (TEM) represents an outstanding method to study the uptake and intracellular fate of NPs, since this technique provides a resolution far better than the particle size. Additionally, its capability to highlight ultrastructural details of the cellular interior as well as membrane features is unmatched by other approaches. Here, a summary is provided on studies utilizing TEM to investigate the uptake and mode-of-action of tailor-made polymer nanoparticles in mammalian cells. For this purpose, the capabilities as well as limitations of TEM investigations are discussed to provide a detailed overview on uptake studies of common nanoparticle systems supported by TEM investigations. Furthermore, methodologies that can, in particular, address low-contrast materials in electron microscopy, i.e., polymeric and polymer-modified nanoparticles, are highlighted.

A 3D magnetic tissue stretcher for remote mechanical control of embryonic stem cell differentiation

The ability to create a 3D tissue structure from individual cells and then to stimulate it at will is a major goal for both the biophysics and regenerative medicine communities. Here we show an integrated set of magnetic techniques that meet this challenge using embryonic stem cells (ESCs). We assessed the impact of magnetic nanoparticles internalization on ESCs viability, proliferation, pluripotency and differentiation profiles. We developed magnetic attractors capable of aggregating the cells remotely into a 3D embryoid body. This magnetic approach to embryoid body formation has no discernible impact on ESC differentiation pathways, as compared to the hanging drop method. It is also the base of the final magnetic device, composed of opposing magnetic attractors in order to form embryoid bodies in situ, then stretch them, and mechanically stimulate them at will. These stretched and cyclic purely mechanical stimulations were sufficient to drive ESCs differentiation towards the mesodermal cardiac pathway.

The development of embryoid bodies that are responsive to external stimuli is of great interest in tissue engineering. Here, the authors culture embryonic stem cells with magnetic nanoparticles and show that the presence of magnetic fields could affect their aggregation and differentiation.

Nanoparticles for bone tissue engineering

Tissue engineering (TE) envisions the creation of functional substitutes for damaged tissues through integrated solutions, where medical, biological, and engineering principles are combined. Bone regeneration is one of the areas in which designing a model that mimics all tissue properties is still a challenge. The hierarchical structure and high vascularization of bone hampers a TE approach, especially in large bone defects. Nanotechnology can open up a new era for TE, allowing the creation of nanostructures that are comparable in size to those appearing in natural bone. Therefore, nanoengineered systems are now able to more closely mimic the structures observed in naturally occurring systems, and it is also possible to combine several approaches - such as drug delivery and cell labeling - within a single system. This review aims to cover the most recent developments on the use of different nanoparticles for bone TE, with emphasis on their application for scaffolds improvement; drug and gene delivery carriers, and labeling techniques. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:590-611, 2017.

Clinical Impact and Cellular Mechanisms of Iron Overload-Associated Bone Loss

Diseases/conditions with diverse etiology, such as hemoglobinopathies, hereditary hemochromatosis and menopause, could lead to chronic iron accumulation. This condition is frequently associated with a bone phenotype; characterized by low bone mass, osteoporosis/osteopenia, altered microarchitecture and biomechanics, and increased incidence of fractures. Osteoporotic bone phenotype constitutes a major complication in patients with iron overload. The purpose of this review is to summarize what we have learnt about iron overload-associated bone loss from clinical studies and animal models. Bone is a metabolically active tissue that undergoes continuous remodeling with the involvement of osteoclasts that resorb mineralized bone, and osteoblasts that form new bone. Growing evidence suggests that both increased bone resorption and decreased bone formation are involved in the pathological bone-loss in iron overload conditions. We will discuss the cellular and molecular mechanisms that are involved in this detrimental process. Fuller understanding of this complex mechanism may lead to the development of improved therapeutics meant to interrupt the pathologic effects of excess iron on bone.

Strategies to reduce the intracellular effects of iron oxide nanoparticle degradation

Mesenchymal stem cells (MSCs) have a significant self-renewal capacity and can differentiate into a variety of cell types. Cell labeling is crucial as it is difficult to detect cell fate after transplantation in vivo. MSCs labeled with iron oxide nanoparticles (IONPs), which can be tracked by MRI, have tremendous potential in regenerative medicine and oncological research. As a part of nanoparticle, the iron oxide core is a key aspect that can exhibit adverse or beneficial effects on MSCs labeled for tracking. Some IONPs exhibit adverse effects, such as cytotoxicity and apoptosis, while other IONPs exhibit beneficial functions that can promote both MSC proliferation and homing efficiency. This review reveals the cytotoxic mechanisms and potential functions of the iron oxide core of IONPs in cell labeling as well as strategies for minimizing the intracellular effects of IONPs.

A comprehensive literatures update of clinical researches of superparamagnetic resonance iron oxide nanoparticles for magnetic resonance imaging

This paper aims to update the clinical researches using superparamagnetic iron oxide (SPIO) nanoparticles as magnetic resonance imaging (MRI) contrast agent published during the past five years. PubMed database was used for literature search, and the search terms were (SPIO OR superparamagnetic iron oxide OR Resovist OR Ferumoxytol OR Ferumoxtran-10) AND (MRI OR magnetic resonance imaging). The literature search results show clinical research on SPIO remains robust, particularly fuelled by the approval of ferumoxytol for intravenously administration. SPIOs have been tested on MR angiography, sentinel lymph node detection, lymph node metastasis evaluation; inflammation evaluation; blood volume measurement; as well as liver imaging. Two experimental SPIOs with unique potentials are also discussed in this review. A curcumin-conjugated SPIO can penetrate brain blood barrier (BBB) and bind to amyloid plaques in Alzheime's disease transgenic mice brain, and thereafter detectable by MRI. Another SPIO was fabricated with a core of Fe3O4 nanoparticle and a shell coating of concentrated hydrophilic polymer brushes and are almost not taken by peripheral macrophages as well as by mononuclear phagocytes and reticuloendothelial system (RES) due to the suppression of non-specific protein binding caused by their stealthy ''brush-afforded'' structure. This SPIO may offer potentials for the applications such as drug targeting and tissue or organ imaging other than liver and lymph nodes.

Evaluation of Magnetic Nanoparticle-Labeled Chondrocytes Cultivated on a Type II Collagen-Chitosan/Poly(Lactic-co-Glycolic) Acid Biphasic Scaffold

Chondral or osteochondral defects are still controversial problems in orthopedics. Here, chondrocytes labeled with magnetic nanoparticles were cultivated on a biphasic, type II collagen-chitosan/poly(lactic-co-glycolic acid) scaffold in an attempt to develop cultures with trackable cells exhibiting growth, differentiation, and regeneration. Rabbit chondrocytes were labeled with magnetic nanoparticles and characterized by scanning electron microscopy (SEM), transmission electron (TEM) microscopy, and gene and protein expression analyses. The experimental results showed that the magnetic nanoparticles did not affect the phenotype of chondrocytes after cell labeling, nor were protein and gene expression affected. The biphasic type II collagen-chitosan/poly(lactic-co-glycolic) acid scaffold was characterized by SEM, and labeled chondrocytes showed a homogeneous distribution throughout the scaffold after cultivation onto the polymer. Cellular phenotype remained unaltered but with increased gene expression of type II collagen and aggrecan, as indicated by cell staining, indicating chondrogenesis. Decreased SRY-related high mobility group-box gene (Sox-9) levels of cultured chondrocytes indicated that differentiation was associated with osteogenesis. These results are encouraging for the development of techniques for trackable cartilage regeneration and osteochondral defect repair which may be applied in vivo and, eventually, in clinical trials.

Fe3O4/BSA particles induce osteogenic differentiation of mesenchymal stem cells under static magnetic field

Differentiation of stem cells is influenced by many factors, yet uptake of the magnetic particles with or without magnetic field is rarely tackled. In this study, iron oxide nanoparticles-loaded bovine serum albumin (BSA) (Fe₃O₄/BSA) particles were prepared, which showed a spherical morphology with a diameter below 200 nm, negatively charged surface, and tunable magnetic property. The particles could be internalized into bone marrow mesenchymal stem cells (MSCs), and their release from the cells was significantly retarded under external magnetic field, resulting in almost twice intracellular amount of the particles within 21 d compared to that of the magnetic field free control. Uptake of the Fe₃O₄/BSA particles enhanced significantly the osteogenic differentiation of MSCs under a static magnetic field, as evidenced by elevated alkaline phosphatase (ALP) activity, calcium deposition, and expressions of collagen type I and osteocalcin at both mRNA and protein levels. Therefore, uptake of the Fe₃O₄/BSA particles brings significant influence on the differentiation of MSCs under magnetic field, and thereby should be paid great attention for practical applications.

STATEMENT OF SIGNIFICANCE

Differentiation of stem cells is influenced by many factors, yet uptake of the magnetic particles with or without magnetic field is rarely tackled. In this study, iron oxide nanoparticles-loaded bovine serum albumin (BSA) (Fe₃O₄/BSA) particles with a diameter below 200nm, negatively charged surface, tunable Fe₃O₄ content and subsequently adjustable magnetic property were prepared. The particles could be internalized into bone marrow mesenchymal stem cells (MSCs), and their release from the cells was significantly retarded under external magnetic field. Uptake of the Fe₃O₄/BSA particles enhanced significantly the osteogenic differentiation of MSCs under a constant static magnetic field, while the magnetic particles and external magnetic field alone do not influence significantly the osteogenic differentiation potential of MSCs regardless of the uptake amount. The results demonstrate a potential magnetic manipulation method for stem cell differentiation, and also convey the significance of careful evaluation of the safety issue of magnetic particles in real an application situation.

Massive Intracellular Biodegradation of Iron Oxide Nanoparticles Evidenced Magnetically at Single-Endosome and Tissue Levels

Quantitative studies of the long-term fate of iron oxide nanoparticles inside cells, a prerequisite for regenerative medicine applications, are hampered by the lack of suitable biological tissue models and analytical methods. Here, we propose stem-cell spheroids as a tissue model to track intracellular magnetic nanoparticle transformations during long-term tissue maturation. We show that global spheroid magnetism can serve as a fingerprint of the degradation process, and we evidence a near-complete nanoparticle degradation over a month of tissue maturation, as confirmed by electron microscopy. Remarkably, the same massive degradation was measured at the endosome level by single-endosome nanomagnetophoretic tracking in cell-free endosomal extract. Interestingly, this spectacular nanoparticle breakdown barely affected iron homeostasis: only the genes coding for ferritin light chain (iron loading) and ferroportin (iron export) were up-regulated 2-fold by the degradation process. Besides, the magnetic and tissular tools developed here allow screening of the biostability of magnetic nanomaterials, as demonstrated with iron oxide nanocubes and nanodimers. Hence, stem-cell spheroids and purified endosomes are suitable models needed to monitor nanoparticle degradation in conjunction with magnetic, chemical, and biological characterizations at the cellular scale, quantitatively, in the long term, in situ, and in real time.

Autonomous magnetic labelling of functional mesenchymal stem cells for improved traceability and spatial control in cell therapy applications

Mesenchymal stem cells (MSCs) represent a valuable resource for regenerative medicine treatments for orthopaedic repair and beyond. Following developments in isolation, expansion and differentiation protocols, efforts to promote clinical translation of emerging cellular strategies now seek to improve cell delivery and targeting. This study shows efficient live MSC labelling using silica‐coated magnetic particles (MPs), which enables 3D tracking and guidance of stem cells. A procedure developed for the efficient and unassisted particle uptake was shown to support MSC viability and integrity, while surface marker expression and MSC differentiation capability were also maintained. In vitro, MSCs showed a progressive decrease in labelling over increasing culture time, which appeared to be linked to the dilution effect of cell division, rather than to particle release, and did not lead to detectable secondary particle uptake. Labelled MSC populations demonstrated magnetic responsiveness in vitro through directed migration in culture and, when seeded onto a scaffold, supporting MP‐based approaches to cell targeting. The potential of these silica‐coated MPs for MRI cell tracking of MSC populations was validated in 2D and in a cartilage repair model following cell delivery. These results highlight silica‐coated magnetic particles as a simple, safe and effective resource to enhance MSC targeting for therapeutic applications and improve patient outcomes. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.

Multimodal iron oxide (Fe3O4)-saturated lactoferrin nanocapsules as nanotheranostics for real-time imaging and breast cancer therapy of claudin-low, triple-negative (ER-/PR-/HER2-)

Aim: To unravel the multimodal nanotheranostic ability of Fe3O4-saturated bovine lactoferrin nanocapsules (FebLf NCs) in claudin-low, triple-negative breast cancer model. Materials & methods: Xenograft study was performed to examine biocompatibility, antitumor efficacy and multimodal nanotheranostic action in combination with near-infrared live mice imaging. Results: FebLf NCs exhibited a size range of 80 nm ± 5 nm with observed superparamagnetism. FebLf NCs successfully internalized into breast cancer cells through receptor-mediated endocytosis and induced apoptosis through the downregulation of inhibitor of apoptosis survivin and livin proteins. Investigations revealed a remarkable biocompatibility, anticancer efficacy of the FebLf NCs. Near-infrared imaging observations confirmed selective localization of multimodal FebLf NCs at the tumor site and lead to time-dependent reduction of tumor growth. Conclusion: FebLf NCs can be safe, biocompatible nanotheranostic approach for real-time imaging and monitoring the effect of drugs in real time and have potentials in future clinical trials.

Two novel amino acid-coated super paramagnetic nanoparticles at low concentrations label and promote the proliferation of mesenchymal stem cells

We identified two amino acid-coated magnetic nanoparticles that promoted mesenchymal stem cell growth without the need for transfection agents by increasing the proportion of cells in the S phase.

Citrate-capped iron oxide nanoparticles impair the osteogenic differentiation potential of rat mesenchymal stem cells

The cellular uptake of citrate-capped iron oxide nanoparticles can impair the osteogenic differentiation of MSCs.

In Vitro/In Vivo Toxicity Evaluation and Quantification of Iron Oxide Nanoparticles

Increasing biomedical applications of iron oxide nanoparticles (IONPs) in academic and commercial settings have alarmed the scientific community about the safety and assessment of toxicity profiles of IONPs. The great amount of diversity found in the cytotoxic measurements of IONPs points toward the necessity of careful characterization and quantification of IONPs. The present document discusses the major developments related to in vitro and in vivo toxicity assessment of IONPs and its relationship with the physicochemical parameters of IONPs. Major discussion is included on the current spectrophotometric and imaging based techniques used for quantifying, and studying the clearance and biodistribution of IONPs. Several invasive and non-invasive quantification techniques along with the pitfalls are discussed in detail. Finally, critical guidelines are provided to optimize the design of IONPs to minimize the toxicity.

A Nanoparticle-based Sensor Platform for Cell Tracking and Status/Function Assessment

Nanoparticles are increasingly popular choices for labeling and tracking cells in biomedical applications such as cell therapy. However, all current types of nanoparticles fail to provide real-time, noninvasive monitoring of cell status and functions while often generating false positive signals. Herein, a nanosensor platform to track the real-time expression of specific biomarkers that correlate with cell status and functions is reported. Nanosensors are synthesized by encapsulating various sensor molecules within biodegradable polymeric nanoparticles. Upon intracellular entry, nanosensors reside within the cell cytoplasm, serving as a depot to continuously release sensor molecules for up to 30 days. In the absence of the target biomarkers, the released sensor molecules remain 'Off'. When the biomarker(s) is expressed, a detectable signal is generated (On). As a proof-of-concept, three nanosensor formulations were synthesized to monitor cell viability, secretion of nitric oxide, and β-actin mRNA expression.

Preclinical good laboratory practice-compliant safety study to evaluate biodistribution and tumorigenicity of a cartilage advanced therapy medicinal product (ATMP)

BACKGROUND

The clinical development of advanced therapy medicinal products (ATMPs), a new class of drugs, requires initial safety studies that deviate from standard non-clinical safety protocols. The study provides a strategy to address the safety aspects of biodistribution and tumorigenicity of ATMPs under good laboratory practice (GLP) conditions avoiding cell product manipulation. Moreover, the strategy was applied on a human ATMP for cartilage repair.

METHODS

The testing strategy addresses biodistribution and tumorigenicity using a multi-step analysis without any cell manipulation to exclude changes of test item characteristics. As a safeguard measurement for meeting regulatory expectations, the project design and goals were discussed continuously with the regulatory authority using a staggered scientific advice concept. Subsequently, the strategy was applied to co.don chondrosphere® (huChon spheroid), a tissue-engineered matrix-free ATMP of human normal chondrocytes. In both the biodistribution and tumorigenicity studies, huChon spheroids were implanted subcutaneously into 40 immunodeficient mice. Biodistribution was studied 1 month after implantation. A skin disc containing the huChon spheroid, two surrounding skin rings and selected organs were analyzed by validated, gender-specific, highly-sensitive triplex qPCR and by immunohistochemistry (IHC).

RESULTS

No human DNA was detected in distant skin rings and analyzed organs. IHC revealed no direct or indirect indications of cell migration. Tumorigenicity was assessed 6 months after huChon spheroid implantation by palpation, macroscopic inspection, histology and IHC. No mice from the huChon spheroid group developed a tumor at the implantation site. In two mice, benign tumors were detected that were negative for HLA-ABC, suggesting that they were of spontaneous murine origin.

CONCLUSIONS

In summary, the presented strategy using a multi-step analysis was confirmed to be suitable for safety studies of ATMPs.

Biological characteristics of adipose tissue-derived stem cells labeled with amine-surface-modified superparamagnetic iron oxide nanoparticles

Cell labeling and tracking are becoming increasingly important areas within the field of stem cell transplantation. The ability to track the migration and distribution of implanted cells is critical to understanding the beneficial effects and mechanisms of stem cell therapy. The present study investigated the effects of amine-surface-modified superparamagnetic iron oxide (SPIO) nanoparticles on the biological properties of human adipose tissue-derived stem cells (hADSCs). Monodisperse hydrophobic magnetite (Fe3 O4 ) nanoparticles were prepared using silicon and surface-modified with amine coating. Cell viability, proliferation, differentiation potential, and surface marker expression were evaluated. The magnetic particles (10-18 nm) displayed high labeling efficiency and stability in hADSCs. SPIO-labeled cells produced a hypointense signal and were effectively visualized by MRI for up to 21 days. The results of MTT proliferation assays and flow cytometry analysis demonstrated that SPIOs were biocompatible, viz. the labeling process did not cause cell death or apoptosis and had no side effects on cell proliferation. In vivo experiments showed that the magnetic particles did not affect liver and kidney function. The successful and stable labeling of hADSCs combined with efficient magnetic tropism demonstrates that SPIOs are promising candidates for hADSC tracking in hADSC-based cell therapy applications.

In vitro 30 nm silver nanoparticles promote chondrogenesis of human mesenchymal stem cells

Silver nanoparticles positively influence chondrogenesis of human mesenchymal stem cells through promoting expression of chondrogenic markers while reducing hypertrophy.

Tracking mesenchymal stem cell tumor-homing using fluorescent silica nanoparticles

Core–shell fluorescent silica nanoparticles for in vitro and in vivo tracking of tumor tropism of human mesenchymal stem cells.

Mesenchymal stromal cell labeling by new uncoated superparamagnetic maghemite nanoparticles in comparison with commercial Resovist--an initial in vitro study

OBJECTIVE

Cell therapies have emerged as a promising approach in medicine. The basis of each therapy is the injection of 1-100×10(6) cells with regenerative potential into some part of the body. Mesenchymal stromal cells (MSCs) are the most used cell type in the cell therapy nowadays, but no gold standard for the labeling of the MSCs for magnetic resonance imaging (MRI) is available yet. This work evaluates our newly synthesized uncoated superparamagnetic maghemite nanoparticles (surface-active maghemite nanoparticles - SAMNs) as an MRI contrast intracellular probe usable in a clinical 1.5 T MRI system.

METHODS

MSCs from rat and human donors were isolated, and then incubated at different concentrations (10-200 μg/mL) of SAMN maghemite nanoparticles for 48 hours. Viability, proliferation, and nanoparticle uptake efficiency were tested (using fluorescence microscopy, xCELLigence analysis, atomic absorption spectroscopy, and advanced microscopy techniques). Migration capacity, cluster of differentiation markers, effect of nanoparticles on long-term viability, contrast properties in MRI, and cocultivation of labeled cells with myocytes were also studied.

RESULTS

SAMNs do not affect MSC viability if the concentration does not exceed 100 μg ferumoxide/mL, and this concentration does not alter their cell phenotype and long-term proliferation profile. After 48 hours of incubation, MSCs labeled with SAMNs show more than double the amount of iron per cell compared to Resovist-labeled cells, which correlates well with the better contrast properties of the SAMN cell sample in T2-weighted MRI. SAMN-labeled MSCs display strong adherence and excellent elasticity in a beating myocyte culture for a minimum of 7 days.

CONCLUSION

Detailed in vitro tests and phantom tests on ex vivo tissue show that the new SAMNs are efficient MRI contrast agent probes with exclusive intracellular uptake and high biological safety.

Comparative in vitro study on magnetic iron oxide nanoparticles for MRI tracking of adipose tissue-derived progenitor cells

Magnetic resonance imaging (MRI) using measurement of the transverse relaxation time (R2*) is to be considered as a promising approach for cell tracking experiments to evaluate the fate of transplanted progenitor cells and develop successful cell therapies for tissue engineering. While the relationship between core composition of nanoparticles and their MRI properties is well studied, little is known about possible effects on progenitor cells. This in vitro study aims at comparing two magnetic iron oxide nanoparticle types, single vs. multi-core nanoparticles, regarding their physico-chemical characteristics, effects on cellular behavior of adipose tissue-derived stem cells (ASC) like differentiation and proliferation as well as their detection and quantification by means of MRI. Quantification of both nanoparticle types revealed a linear correlation between labeling concentration and R2* values. However, according to core composition, different levels of labeling concentrations were needed to achieve comparable R2* values. Cell viability was not altered for all labeling concentrations, whereas the proliferation rate increased with increasing labeling concentrations. Likewise, deposition of lipid droplets as well as matrix calcification revealed to be highly dose-dependent particularly regarding multi-core nanoparticle-labeled cells. Synthesis of cartilage matrix proteins and mRNA expression of collagen type II was also highly dependent on nanoparticle labeling. In general, the differentiation potential was decreased with increasing labeling concentrations. This in vitro study provides the proof of principle for further in vivo tracking experiments of progenitor cells using nanoparticles with different core compositions but also provides striking evidence that combined testing of biological and MRI properties is advisable as improved MRI properties of multi-core nanoparticles may result in altered cell functions.

Perturbation of physiological systems by nanoparticles

Nanotechnology is having a tremendous impact on our society. However, societal concerns about human safety under nanoparticle exposure may derail the broad application of this promising technology. Nanoparticles may enter the human body via various routes, including respiratory pathways, the digestive tract, skin contact, intravenous injection, and implantation. After absorption, nanoparticles are carried to distal organs by the bloodstream and the lymphatic system. During this process, they interact with biological molecules and perturb physiological systems. Although some ingested or absorbed nanoparticles are eliminated, others remain in the body for a long time. The human body is composed of multiple systems that work together to maintain physiological homeostasis. The unexpected invasion of these systems by nanoparticles disturbs normal cell signaling, impairs cell and organ functions, and may even cause pathological disorders. This review examines the comprehensive health risks of exposure to nanoparticles by discussing how nanoparticles perturb various physiological systems as revealed by animal studies. The potential toxicity of nanoparticles to each physiological system and the implications of disrupting the balance among systems are emphasized.