Increased cellular uptake of biocompatible superparamagnetic iron oxide nanoparticles into malignant cells by an external magnetic field

Advances in screening hyperthermic nanomedicines in 3D tumor models

Hyperthermic nanomedicines are particularly relevant for tackling human cancer, providing a valuable alternative to conventional therapeutics. The early-stage preclinical performance evaluation of such anti-cancer treatments is conventionally performed in flat 2D cell cultures that do not mimic the volumetric heat transfer occurring in human tumors. Recently, improvements in bioengineered 3D in vitro models have unlocked the opportunity to recapitulate major tumor microenvironment hallmarks and generate highly informative readouts that can contribute to accelerating the discovery and validation of efficient hyperthermic treatments. Leveraging on this, herein we aim to showcase the potential of engineered physiomimetic 3D tumor models for evaluating the preclinical efficacy of hyperthermic nanomedicines, featuring the main advantages and design considerations under diverse testing scenarios. The most recent applications of 3D tumor models for screening photo- and/or magnetic nanomedicines will be discussed, either as standalone systems or in combinatorial approaches with other anti-cancer therapeutics. We envision that breakthroughs toward developing multi-functional 3D platforms for hyperthermia onset and follow-up will contribute to a more expedited discovery of top-performing hyperthermic therapies in a preclinical setting before their in vivo screening.

Photocatalytic Degradation of Antibiotics via Exploitation of a Magnetic Nanocomposite: A Green Nanotechnology Approach toward Drug-Contaminated Wastewater Reclamation

In the quest for eco-conscious innovations, this research was designed for the sustainable synthesis of magnetite (Fe3O4) nanoparticles, using ferric chloride hexahydrate salt as a precursor and extract of Eucalyptus globulus leaves as both a reducing and capping agent, which are innovatively applied as a photocatalyst for the photocatalytic degradation of antibiotics "ciprofloxacin and amoxicillin". Sugar cane bagasse biomass, sugar cane bagasse pyrolyzed biochar, and magnetite/sugar cane bagasse biochar nanocomposite were also synthesized via environmentally friendly organized approaches. The optimum conditions for the degradation of ciprofloxacin and amoxicillin were found to be pH 6 for ciprofloxacin and 5 for amoxicillin, dosage of the photocatalyst (0.12 g), concentration (100 mg/L), and irradiation time (240 min). The maximum efficiencies of percentage degradation for ciprofloxacin and amoxicillin were found to be (73.51%) > (63.73%) > (54.57%) and (74.07%) > (61.55%) > (50.66%) for magnetic nanocomposites, biochar, and magnetic nanoparticles, respectively. All catalysts demonstrated favorable performance; however, the "magnetite/SCB biochar" nanocomposite exhibited the most promising results among the various catalysts employed in the photocatalytic degradation of antibiotics. Kinetic studies for the degradation of antibiotics were also performed, and notably, the pseudo-first-order chemical reaction showed the best results for the degradation of antibiotics. Through a comprehensive and comparative analysis of three unique photocatalysts, this research identified optimal conditions for efficient treatment of drug-contaminated wastewater, thus amplifying the practical significance of the findings. The recycling of magnetic nanoparticles through magnetic separation, coupled with their functional modification for integration into composite materials, holds significant application potential in the degradation of antibiotics.

HER2 aptamer-conjugated iron oxide nanoparticles with PDMAEMA-b-PMPC coating for breast cancer cell identification

Aim: To synthesize HER2 aptamer-conjugated iron oxide nanoparticles with a coating of poly(2-(dimethylamino) ethyl methacrylate)-poly(2-methacryloyloxyethylphosphorylcholine) block copolymer (IONPPPs). Methods: Characterization covered molecular structure, chemical composition, thermal stability, magnetic characteristics, aptamer interaction, crystalline nature and microscopic features. Subsequent investigations focused on IONPPPs for in vitro cancer cell identification. Results: Results demonstrated high biocompatibility of the diblock copolymer with no significant toxicity up to 150 μg/ml. The facile coating process yielded the IONPP complex, featuring a 13.27 nm metal core and a 3.10 nm polymer coating. Functionalized with a HER2-targeting DNA aptamer, IONPPP enhanced recognition in HER2-amplified SKBR3 cells via magnetization separation. Conclusion: These findings underscore IONPPP's potential in cancer research and clinical applications, showcasing diagnostic efficacy and HER2 protein targeting in a proof-of-concept approach.

Mesenchymal stromal cell-derived magnetic nanovesicles for enhanced skin retention and hair follicle growth

BACKGROUND AIMS

Extracellular vesicles and exosome-mimetic nanovesicles (NVs) derived from mesenchymal stromal cells (MSCs) have emerged as promising to promote hair growth. However, short local skin retention after subcutaneous administration hinders their clinical applications.

METHODS

In this study, we prepared magnetic nanovesicles (MNVs) from iron oxide nanoparticle-incorporated MSCs. MNVs contained more therapeutic growth factors than NVs derived from naive MSCs, and their localization and internalization were manipulated by external magnetic field.

RESULTS

Following the subcutaneous injection of MNVs into a mouse model of depilation-induced hair regeneration, the magnetic attraction increased their skin retention. Then, the cellular proliferation and β-catenin signaling in hair follicles (HF) were markedly enhanced by MNV injection and magnetic field application. Furthermore, an acceleration of HF growth was revealed by histological analysis.

CONCLUSIONS

The proposed strategy can enhance the therapeutic potential of MSC-derived NVs for hair regeneration and other dermatological diseases.

Bioactive superparamagnetic iron oxide-gold nanoparticles regulated by a dynamic magnetic field induce neuronal Ca2+ influx and differentiation

Treating neurodegenerative diseases, e.g., Alzheimer's Disease, remains a significant challenge due to the limited neuroregeneration rate in the brain. The objective of this study is to evaluate the hypothesis that external magnetic field (MF) stimulation of nerve growth factor functionalized superparamagnetic iron oxide-gold (NGF-SPIO-Au) nanoparticles (NPs) can induce Ca²⁺ influx, membrane depolarization, and enhance neuron differentiation with dynamic MF (DMF) outperforming static MF (SMF) regulation. We showed the that total intracellular Ca²⁺ influx of PC-12 cells was improved by 300% and 535% by the stimulation of DMF (1 Hz, 0.5 T, 30min) with NGF-SPIO-Au NPs compared to DMF alone and SMF with NGF-SPIO-Au NPs, respectively, which was attributed to successive membrane depolarization. Cellular uptake performed with the application of sodium azide proved that DMF enhanced cellular uptake of NGF-SPIO-Au NPs via endocytosis. In addition, DMF upregulated both the neural differentiation marker (β3-tubulin) and the cell adhesive molecule (integrin-β1) with the existence of NGF-SPIO-Au NPs, while SMF did not show these effects. The results imply that noninvasive DMF-stimulated NPs can regulate intracellular Ca²⁺ influx and enhance neuron differentiation and neuroregeneration rate.

Force-Mediated Endocytosis of Iron Oxide Nanoparticles for Magnetic Targeting of Stem Cells

Stem cell therapy represents one of the most promising approaches for tissue repair and regeneration. However, the full potential of stem cell therapy remains to be realized. One major challenge is the insufficient homing and retention of stem cells at the desired sites after in vivo delivery. Here, we provide a proof-of-principle demonstration of magnetic targeting and retention of human muscle-derived stem cells (hMDSCs) in vitro through magnetic force-mediated internalization of magnetic iron oxide nanoparticles (MIONs) and the use of a micropatterned magnet. We found that the magnetic force-mediated cellular uptake of MIONs occurs through an endocytic pathway, and the MIONs were exclusively localized in the lysosomes. The intracellular MIONs had no detrimental effect on the proliferation of hMDSCs or their multilineage differentiation, and no MIONs were translocated to other cells in a coculture system. Using hMDSCs and three other cell types including human umbilical vein endothelial cells (HUVECs), human dermal fibroblasts (HDFs), and HeLa cells, we further discovered that the magnetic force-mediated MION uptake increased with MION size and decreased with cell membrane tension. We found that the cellular uptake rate was initially increased with MION concentration in solution and approached saturation. These findings provide important insight and guidance for magnetic targeting of stem cells in therapeutic applications.

Superparamagnetic Iron-Oxide Nanoparticles Synthesized via Green Chemistry for the Potential Treatment of Breast Cancer

In the emerging field of nanomedicine, nanoparticles have been widely considered as drug carriers and are now used in various clinically approved products. Therefore, in this study, we synthesized superparamagnetic iron-oxide nanoparticles (SPIONs) via green chemistry, and the SPIONs were further coated with tamoxifen-conjugated bovine serum albumin (BSA-SPIONs-TMX). The BSA-SPIONs-TMX were within the nanometric hydrodynamic size (117 ± 4 nm), with a small poly dispersity index (0.28 ± 0.02) and zeta potential of -30.2 ± 0.09 mV. FTIR, DSC, X-RD, and elemental analysis confirmed that BSA-SPIONs-TMX were successfully prepared. The saturation magnetization (M_s) of BSA-SPIONs-TMX was found to be ~8.31 emu/g, indicating that BSA-SPIONs-TMX possess superparamagnetic properties for theragnostic applications. In addition, BSA-SPIONs-TMX were efficiently internalized into breast cancer cell lines (MCF-7 and T47D) and were effective in reducing cell proliferation of breast cancer cells, with IC₅₀ values of 4.97 ± 0.42 μM and 6.29 ± 0.21 μM in MCF-7 and T47D cells, respectively. Furthermore, an acute toxicity study on rats confirmed that these BSA-SPIONs-TMX are safe for use in drug delivery systems. In conclusion, green synthesized superparamagnetic iron-oxide nanoparticles have the potential to be used as drug delivery carriers and may also have diagnostic applications.

Preparation of a 3D printable high-performance GelMA hydrogel loading with magnetic cobalt ferrite nanoparticles

Osteosarcoma remains a worldwide concern due to the poor effectiveness of available therapies in the clinic. Therefore, it is necessary to find a safe and effective therapy to realize the complete resection of osteosarcoma and reconstruction of the bone defect. Magnetic hyperthermia based on magnetic nanoparticles can kill tumor cells by raising the temperature without causing the side effects of conventional cancer treatments. This research aims to design a high-performance magnetic hydrogel composed of gelatin methacrylate and highly magnetic cobalt ferrite (CFO) nanoparticles for osteosarcoma treatment. Specifically, CFO is surface functionalized with methacrylate groups (MeCFO). The surface modified CFO has good biocompatibility and stable solution dispersion ability. Afterward, MeCFO nanoparticles are incorporated into GelMA to fabricate a three-dimensional (3D) printable MeCFO/GelMA magnetic hydrogel and then photocross-linked by UV radiation. MeCFO/GelMA hydrogel has high porosity and swelling ability, indicating that the hydrogel possesses more space and good hydrophily for cell survival. The rheological results showed that the hydrogel has shear thinning property, which is suitable as a bioprinting ink to produce desired structures by a 3D printer. Furthermore, 50 μg/mL MeCFO not only decreases the cell activity of osteosarcoma cells but also promotes the osteogenic differentiation of mBMSCs. The results of the CCK-8 assay and live/dead staining showed that MeCFO/GelMA hydrogel had good cytocompatibility. These results indicated that MeCFO/GelMA hydrogel with potential antitumor and bone reconstruction functions is a promising therapeutic strategy after osteosarcoma resection.

Interfacial engineered iron oxide nanoring for T2-weighted magnetic resonance imaging-guided magnetothermal-chemotherapy

Due to no penetration depth limitation, low cost, and easy control, magnetic nanoparticles mediated magnetic hyperthermia therapy (MHT) has shown great potential in experimental and clinal treatments of various diseases. However, the low heating conversion efficiencies and short circulation times are major drawback for most existing magnetic-thermal materials. Additionally, single MHT treatment always leads to resistance and recurrence. Herein, a highly efficient magnetic-thermal conversion, ferrimagnetic vortex nanoring Fe₃O₄ coated with hyaluronic acid (HA) nanoparticles (Fe₃O₄@HA, FVNH NPs) was firstly constructed. Additionally, the doxorubicin (DOX) was successfully enclosed inside the FVNH and released remotely for synergetic magnetic–thermal/chemo cancer therapy. Due to the ferrimagnetic vortex-domain state, the ring shape Fe₃O₄ displays a high specific absorption rate (SAR) under an external alternating magnetic field (AMF). Additionally, antitumor drug (DOX) can be encapsulated inside the single large hole of FVNH by the hyaluronic acid (HA) shell and quickly released in response the tumor acidic microenvironments and AMF. What’s more, the non-loaded FVNH NPs show good biocompatibility but high cytotoxicity after loading DOX under AMF. Furthermore, the synthesized FVNH can efficiently reduce the transverse relaxation time and enhance negative magnetic resonance imaging (MRI). The impressive in vivo systemic therapeutic efficacy of FVNH was also proved in this work. Taken together, the results of this study demonstrate that the synthesized FVNH NPs offer the promise of serving as multifunctional theranostic nanoplatforms for medical imaging-guided tumor therapies.

Toxicological effects of the mixed iron oxide nanoparticle (Fe3O4 NP) on murine fibroblasts LA-9

The increase in large-scale production of magnetic nanoparticles (NP) associated with the incomplete comprehensive knowledge regarding the potential risks of their use on environmental and human health makes it necessary to study the biological effects of these particles on organisms at the cellular level. The aim of this study to examine the cellular effects on fibroblast lineage LA-9 after exposure to mixed iron oxide NP (Fe₃O₄ NP). The following analyses were performed: field emission gun-scanning electron microscopy (SEM-FEG), dynamic light scattering (DLS), zeta potential, ultraviolet/visible region spectroscopy (UV/VIS), and attenuated total reactance-Fourier transform infrared (ATR-FTIR) spectroscopy analyses for characterization of the NP. The assays included cell viability, morphology, clonogenic potential, oxidative stress as measurement of reactive oxygen species (ROS) and nitric oxide (NO) levels, cytokines quantification interleukin 6 (IL-6) and tumor necrosis factor (TNF), NP uptake, and cell death. The size of Fe₃O₄ NP was 26.3 nm when evaluated in water through DLS. Fe₃O₄ NP did not reduce fibroblast cell viability until the highest concentration tested (250 µg/ml), which showed a decrease in clonogenic potential as well as small morphological changes after exposure for 48 and 72 hr. The NP concentration of 250 µg/ml induced enhanced ROS and NO production after 24 hr treatment. The uptake assay exhibited time-dependent Fe₃O₄ NP internalization at all concentrations tested with no significant cell death. Hence, exposure of fibroblasts to Fe₃O₄ NP-induced oxidative stress but not reduced cell viability or death. However, the decrease in the clonogenic potential at the highest concentration demonstrates cytotoxic effects attributed to Fe₃O₄ NP which occurred on the 7^th day after exposure.

Prodigious therapeutic effects of combining mesenchymal stem cells with magnetic nanoparticles

Mesenchymal stem cells (MSCs) have gained wide-ranging reputation in the medical research community due to their promising regenerative abilities. MSCs can be isolated from various resources mostly bone marrow, Adipose tissues and Umbilical cord. Huge advances have been achieved in comprehending the possible mechanisms underlying the therapeutic functions of MSCs. Despite the proven role of MSCs in repairing and healing of many disease modalities, many hurdles hinder the transferring of these cells in the clinical settings. Among the most reported problems encountering MSCs therapy in vivo are loss of tracking signal post-transplantation, insufficient migration, homing and engraftment post-infusion, and undesirable differentiation at the site of injury. Magnetic nanoparticles (MNPs) have been used widely for various biomedical applications. MNPs have a metallic core stabilized by an outer coating material and their magnetic properties can be modulated by an external magnetic field. These magnetic properties of MNPs were found to enhance the quality of diagnostic imaging procedures and can be used to create a carrying system for targeted delivery of therapeutic substances mainly drug, genes and stem cells. Several studies highlighted the advantageous outcomes of combining MSCs with MNPs in potentiating their tracking, monitoring, homing, engraftment and differentiation. In this review, we will discuss the role of MNPs in promoting the therapeutic profile of MSCs which may improve the success rate of MSCs transplantation and solve many challenges that delay their clinical applicability.

Progress, Opportunities, and Challenges of Magneto-Plasmonic Nanoparticles under Remote Magnetic and Light Stimulation for Brain-Tissue and Cellular Regeneration

Finding curable therapies for neurodegenerative disease (ND) is still a worldwide medical and clinical challenge. Recently, investigations have been made into the development of novel therapeutic techniques, and examples include the remote stimulation of nanocarriers to deliver neuroprotective drugs, genes, growth factors, and antibodies using a magnetic field and/or low-power lights. Among these potential nanocarriers, magneto-plasmonic nanoparticles possess obvious advantages, such as the functional restoration of ND models, due to their unique nanostructure and physiochemical properties. In this review, we provide an overview of the latest advances in magneto-plasmonic nanoparticles, and the associated therapeutic approaches to repair and restore brain tissues. We have reviewed their potential as smart nanocarriers, including their unique responsivity under remote magnetic and light stimulation for the controlled and sustained drug delivery for reversing neurodegenerations, as well as the utilization of brain organoids in studying the interaction between NPs and neuronal tissue. This review aims to provide a comprehensive summary of the current progress, opportunities, and challenges of using these smart nanocarriers for programmable therapeutics to treat ND, and predict the mechanism and future directions.

Optimization of Multimodal Nanoparticles Internalization Process in Mesenchymal Stem Cells for Cell Therapy Studies

Considering there are several difficulties and limitations in labeling stem cells using multifunctional nanoparticles (MFNP), the purpose of this study was to determine the optimal conditions for labeling human bone marrow mesenchymal stem cells (hBM-MSC), aiming to monitor these cells in vivo. Thus, this study provides information on hBM-MSC direct labeling using multimodal nanoparticles in terms of concentration, magnetic field, and period of incubation while maintaining these cells’ viability and the homing ability for in vivo experiments. The cell labeling process was assessed using 10, 30, and 50 µg Fe/mL of MFNP, with periods of incubation ranging from 4 to 24 h, with or without a magnetic field, using optical microscopy, near-infrared fluorescence (NIRF), and inductively coupled plasma mass spectrometry (ICP-MS). After the determination of optimal labeling conditions, these cells were applied in vivo 24 h after stroke induction, intending to evaluate cell homing and improve NIRF signal detection. In the presence of a magnetic field and utilizing the maximal concentration of MFNP during cell labeling, the iron load assessed by NIRF and ICP-MS was four times higher than what was achieved before. In addition, considering cell viability higher than 98%, the recommended incubation time was 9 h, which corresponded to a 25.4 pg Fe/cell iron load (86% of the iron load internalized in 24 h). The optimization of cellular labeling for application in the in vivo study promoted an increase in the NIRF signal by 215% at 1 h and 201% at 7 h due to the use of a magnetized field during the cellular labeling process. In the case of BLI, the signal does not depend on cell labeling showing no significant differences between unlabeled or labeled cells (with or without a magnetic field). Therefore, the in vitro cellular optimized labeling process using magnetic fields resulted in a shorter period of incubation with efficient iron load internalization using higher MFNP concentration (50 μgFe/mL), leading to significant improvement in cell detection by NIRF technique without compromising cellular viability in the stroke model.

Azo-functionalized superparamagnetic Fe3O4 nanoparticles: an efficient adsorbent for the removal of bromocresol green from contaminated water

Water contamination is regarded as one of the world's worst tragedies owing to the continual depletion of water resources suitable for drinking and agriculture. Researchers have recently been interested in developing novel and more effective adsorbents for wastewater purification. We report herein a magnetic adsorbent nanomaterial for the removal of the anionic dye bromocresol green (BCG) from wastewater. The adsorbent is based on superparamagnetic iron oxide (cubic Fe₃O₄) nanoparticles (SPIONs) coated with a high-molecular-weight azo dye synthesized via diazo coupling of vitamin B1 with a trisubstituted benzene derivative. The proposed adsorbent was characterized using scanning electron microscopy, FTIR and ¹H-NMR spectroscopy, mass spectrometry, dynamic light scattering, vibrating sample magnetometry, thermal analysis, and X-ray diffraction crystallography. At room temperature and pH 2.0, the synthesized adsorbent showed an average particle size of 65.9 ± 8.0 nm, a high magnetization saturation (65.58 emu g⁻¹), a high equilibrium adsorption capacity (36.91 mg g⁻¹). Adsorption of BCG was found to take place via a physisorption mechanism and followed a pseudo-second-order rate kinetics. Thermodynamic studies revealed that the adsorption process is enthalpy driven by hydrogen bonding and/or van der Waals interactions. After treating water samples with the suggested adsorbent, it can be easily removed from water using a strong external magnetic field.

An efficient adsorbent based on azo-dye-coated superparamagnetic Fe₃O₄ nanoparticles was synthesized for the removal of the anionic dye, bromocresol green, from wastewater.

Non-invasive transferrin targeted nanovesicles sensitize resistant glioblastoma multiforme tumors and improve survival in orthotopic mouse models

The blood-brain barrier (BBB) and tumor heterogeneity have resulted in abysmally poor clinical outcomes in glioblastoma (GBM) with the standard therapeutic regimen. Despite several anti-glioma drug delivery strategies, the lack of adequate chemotherapeutic bioavailability in gliomas has led to a suboptimal therapeutic gain in terms of improvement in survival and increased systemic toxicities. This has paved the way for designing highly specific and non-invasive drug delivery approaches for treating GBM. The intranasal (IN) route is one such delivery strategy that has the potential to reach the brain parenchyma by circumventing the BBB. We recently showed that in situ hydrogel embedded with miltefosine (HePc, proapoptotic anti-tumor agent) and temozolomide (TMZ, DNA methylating agent) loaded targeted nanovesicles prevented tumor relapses in orthotopic GBM mouse models. In this study, we specifically investigated the potential of a non-invasive IN route of TMZ delivered from lipid nanovesicles (LNs) decorated with surface transferrin (Tf) and co-encapsulated with HePc to reach the brain by circumventing the BBB in glioma bearing mice. The targeted nanovesicles (228.3 ± 10 nm, -41.7 ± 4 mV) exhibited mucoadhesiveness with 2% w/v mucin suggesting their potential to increase brain drug bioavailability after IN administration. The optimized TLNs had controlled, tunable and significantly different release kinetics in simulated cerebrospinal fluid and simulated nasal fluid demonstrating efficient release of the payload upon reaching the brain. Drug synergy (combination index, 0.7) showed a 6.4-fold enhanced cytotoxicity against resistant U87MG cells compared to free drugs. In vivo gamma scintigraphy of ^99mTc labeled LNs showed 500- and 280-fold increased brain concentration post 18 h of treatment. The efficacy of the TLNs increased by 1.8-fold in terms of survival of tumor-bearing mice compared to free drugs. These findings suggested that targeted drug synergy has the potential to intranasally deliver a high therapeutic dose of the chemotherapy agent (TMZ) and could serve as a platform for future clinical application.

Bovine Serum Albumin Conjugation in Superparamagnetic/Poly(methyl methacrylate) Nanoparticles as an Alternative for Magnetic Enzyme-Linked Immunosorbent Assays

Nanomaterials, such as magnetic nanoparticles have attracted significant attention of medical area due to their capacity to improve the performance of immunoassays. Therefore the aim of this work was to study the bovine serum albumin (BSA) conjugation in superparamagnetic (MNPs)/poly(methyl methacrylate) (PMMA) nanoparticles with further characterization and application in enzyme-linked immunosorbent (ELISA) assay. The successful conjugation of BSA in MNPs- PMMA nanoparticles was confirmed by several techniques, including light scattering, zeta potential, transmission electron microscopy (TEM) and Lowry protein quantification assay. The superparamagnetic properties were confirmed by vibrating sample magnetometer. BSA conjugated MNPs-PMMA nanoparticles presented higher interactions with antibody than free BSA. The BSA + MNPs-PMMA nanoparticles (magnetic ELISA assay) reduced the time and increased the sensibility of traditional ELISA assay, reinforcing the idea that the use these nanomaterials are an excellent alternative for the immunoassays field.

In Vitro Evaluation of Hyperthermia Magnetic Technique Indicating the Best Strategy for Internalization of Magnetic Nanoparticles Applied in Glioblastoma Tumor Cells

This in vitro study aims to evaluate the magnetic hyperthermia (MHT) technique and the best strategy for internalization of magnetic nanoparticles coated with aminosilane (SPIONAmine) in glioblastoma tumor cells. SPIONAmine of 50 and 100 nm were used for specific absorption rate (SAR) analysis, performing the MHT with intensities of 50, 150, and 300 Gauss and frequencies varying between 305 and 557 kHz. The internalization strategy was performed using 100, 200, and 300 µgFe/mL of SPIONAmine, with or without Poly-L-Lysine (PLL) and filter, and with or without static or dynamic magnet field. The cell viability was evaluated after determination of MHT best condition of SPIONAmine internalization. The maximum SAR values of SPIONAmine (50 nm) and SPIONAmine (100 nm) identified were 184.41 W/g and 337.83 W/g, respectively, using a frequency of 557 kHz and intensity of 300 Gauss (≈23.93 kA/m). The best internalization strategy was 100 µgFe/mL of SPIONAmine (100 nm) using PLL with filter and dynamic magnet field, submitted to MHT for 40 min at 44 °C. This condition displayed 70.0% decreased in cell viability by flow cytometry and 68.1% by BLI. We can conclude that our study is promising as an antitumor treatment, based on intra- and extracellular MHT effects. The optimization of the nanoparticles internalization process associated with their magnetic characteristics potentiates the extracellular acute and late intracellular effect of MHT achieving greater efficiency in the therapeutic process.

Near-infrared light and magnetic field dual-responsive porous silicon-based nanocarriers to overcome multidrug resistance in breast cancer cells with enhanced efficiency

The development of drug delivery systems based on external stimuli-responsive nanocarriers is important to overcome multidrug resistance in breast cancer cells. Herein, iron oxide/gold (Fe3O4/Au) nanoparticles were first fabricated via a simple hydrothermal reaction, and subsequently loaded into porous silicon nanoparticles (PSiNPs) via electrostatic interactions to construct PSiNPs@(Fe3O4/Au) nanocomposites. The as-prepared PSiNPs@(Fe3O4/Au) nanocomposites exhibited excellent super-paramagnetism, photothermal effect, and T2-weight magnetic resonance imaging capability. In particular, with the help of a magnetic field, the cellular uptake of PSiNPs@(Fe3O4/Au) nanocomposites was significantly enhanced in drug-resistant breast cancer cells. Moreover, PSiNPs@(Fe3O4/Au) nanocomposites as carriers showed a high loading and NIR light-triggered release of anticancer drugs. Based on the synergistic effect of magnetic field-enhanced cellular uptake and NIR light-triggered intracellular release, the amount of anticancer drug carried by PSiNPs@(Fe3O4/Au) nanocarriers into the nuclei of drug-resistant breast cancer cells sharply increased, accompanied by improved chemo-photothermal therapeutic efficacy. Finally, PSiNPs@(Fe3O4/Au) nanocomposites under the combined conditions of magnetic field attraction and NIR light irradiation also showed improved anticancer drug penetration and accumulation in three-dimensional multicellular spheroids composed of drug-resistant breast cancer cells, leading to a better growth inhibition effect. Overall, the fabricated PSiNPs@(Fe3O4/Au) nanocomposites demonstrated great potential for the therapy of multidrug-resistant breast cancer in future.

Rapidly Transducing and Spatially Localized Magnetofection Using Peptide-Mediated Non-Viral Gene Delivery Based on Iron Oxide Nanoparticles

Non-viral delivery systems are generally of low efficiency, which limits their use in gene therapy and editing applications. We previously developed a technology termed glycosaminoglycan (GAG)-binding enhanced transduction (GET) to efficiently deliver a variety of cargos intracellularly; our system employs GAG-binding peptides, which promote cell targeting, and cell penetrating peptides (CPPs), which enhance endocytotic cell internalization. Herein, we describe a further modification by combining gene delivery and magnetic targeting with the GET technology. We associated GET peptides, plasmid (p)DNA, and iron oxide superparamagnetic nanoparticles (MNPs), allowing rapid and targeted GET-mediated uptake by application of static magnetic fields in NIH3T3 cells. This produced effective transfection levels (significantly higher than the control) with seconds to minutes of exposure and localized gene delivery two orders of magnitude higher in targeted over non-targeted cell monolayers using magnetic fields (in 15 min exposure delivering GFP reporter pDNA). More importantly, high cell membrane targeting by GET-DNA and MNP co-complexes and magnetic fields allowed further enhancement to endocytotic uptake, meaning that the nucleic acid cargo was rapidly internalized beyond that of GET complexes alone (GET-DNA). Magnetofection by MNPs combined with GET-mediated delivery allows magnetic field-guided local transfection in vitro and could facilitate focused gene delivery for future regenerative and disease-targeted therapies in vivo.

Inorganic-organic Nanomaterials for Therapeutics and Molecular Imaging Applications

Background::

Surface modification of nanoparticles with targeting moieties can be achieved through bioconjugation chemistries to impart new Functionalities. Various polymeric nanoparticles have been used for the formulation of nanoparticles such as naturally-occurring protein cages, virus-like particles, polymeric saccharides, and liposomes. These polymers have been proven to be biocompatible, side effects free and degradable with no toxicity.

Objectives::

This paper reviews available literature on the nanoparticles pharmaceutical and medical applications. The review highlights and updates the customized solutions for selective drug delivery systems that allow high-affinity binding between nanoparticles and the target receptors.

Methods::

Bibliographic databases and web-search engines were used to retrieve studies that assessed the usability of nanoparticles in the pharmaceutical and medical fields. Data were extracted on each system in vivo and in vitro applications, its advantages and disadvantages, and its ability to be chemically and genetically modified to impart new functionalities. Finally, a comparison between naturally occurring and their synthetic counterparts was carried out.

Results::

The results showed that nanoparticles-based systems could have promising applications in diagnostics, cell labeling, contrast agents (Magnetic Resonance Imaging and Computed Tomography), antimicrobial agents, and as drug delivery systems. However, precautions should be taken to avoid or minimize toxic effect or incompatibility of nanoparticles-based systems with the biological systems in case of pharmaceutical or medical applications.

Conclusion::

This review presented a summary of recent developments in the field of pharmaceutical nanotechnology and highlighted the challenges and the merits that some of the nanoparticles- based systems both in vivo and in vitro systems.

Biomimetic Magnetite Nanoparticles as Targeted Drug Nanocarriers and Mediators of Hyperthermia in an Experimental Cancer Model

Simple Summary

The application of simultaneous and different strategies to treat cancer appears a promising therapeutic approach. Herein we proposed the application of chemotherapy combined with a magnetic nanocarrier delivery system to an in vitro and an in vivo experimental mammary carcinoma model. Drug-loaded biomimetic magnetic nanoparticle can be directed and concentrated on the tumor cells or site by the apposition of a magnet. Moreover, these nanoparticles can respond to an alternating magnetic field by developing hyperthermia around 43 °C, a temperature at which tumor cells, but not healthy cells, are particularly sensitive and thus induced to death. Indeed, when this nanoformulation is injected in vivo in the tumor site, and hyperthermia is generated, the combined chemo-thermal therapy mediated by these drug-loaded magnetic nanoparticles have a stronger therapeutic benefit compared to that carried out by the chemotherapeutic alone. These nanoformulation and strategy are thus promising tools for translational applications in cancer therapy.

Abstract

Biomimetic magnetic nanoparticles mediated by magnetosome proteins (BMNPs) are potential innovative tools for cancer therapy since, besides being multifunctional platforms, they can be manipulated by an external gradient magnetic field (GMF) and/or an alternating magnetic field (AMF), mediating targeting and hyperthermia, respectively. We evaluated the cytocompatibility/cytotoxicity of BMNPs and Doxorubicin (DOXO)-BMNPs in the presence/absence of GMF in 4T1 and MCF-7 cells as well as their cellular uptake. We analyzed the biocompatibility and in vivo distribution of BMNPs as well as the effect of DOXO-BMNPs in BALB/c mice bearing 4T1 induced mammary carcinomas after applying GMF and AMF. Results: GMF enhanced the cell uptake of both BMNPs and DOXO-BMNPs and the cytotoxicity of DOXO-BMNPs. BMNPs were biocompatible when injected intravenously in BALB/c mice. The application of GMF on 4T1 tumors after each of the repeated (6×) iv administrations of DOXO-BMNPs enhanced tumor growth inhibition when compared to any other treatment, including that with soluble DOXO. Moreover, injection of DOXO-BMNPs in the tumor combined with application of an AMF resulted in a significant tumor weight reduction. These promising results show the suitability of BMNPs as magnetic nanocarriers for local targeted chemotherapy and as local agents for hyperthermia.

In Vitro Intracellular Hyperthermia of Iron Oxide Magnetic Nanoparticles, Synthesized at High Temperature by a Polyol Process

We report the synthesis of magnetite nanoparticles (IOMNPs) using the polyol method performed at elevated temperature (300 °C) and high pressure. The ferromagnetic polyhedral IOMNPs exhibited high saturation magnetizations at room temperature (83 emu/g) and a maximum specific absorption rate (SAR) of 2400 W/gFe in water. The uniform dispersion of IOMNPs in solid matrix led to a monotonous increase of SAR maximum (3600 W/gFe) as the concentration decreased. Cytotoxicity studies on two cell lines (cancer and normal) using Alamar Blues and Neutral Red assays revealed insignificant toxicity of the IOMNPs on the cells up to a concentration of 1000 μg/mL. The cells internalized the IOMNPs inside lysosomes in a dose-dependent manner, with higher amounts of IOMNPs in cancer cells. Intracellular hyperthermia experiments revealed a significant increase in the macroscopic temperatures of the IOMNPs loaded cell suspensions, which depend on the amount of internalized IOMNPs and the alternating magnetic field amplitude. The cancer cells were found to be more sensitive to the intracellular hyperthermia compared to the normal ones. For both cell lines, cells heated at the same macroscopic temperature presented lower viability at higher amplitudes of the alternating magnetic field, indicating the occurrence of mechanical or nanoscale heating effects.

Characterization of the Shape Anisotropy of Superparamagnetic Iron Oxide Nanoparticles during Thermal Decomposition

Magnetosomes are near-perfect intracellular magnetite nanocrystals found in magnetotactic bacteria. Their synthetic imitation, known as superparamagnetic iron oxide nanoparticles (SPIONs), have found applications in a variety of (nano)medicinal fields such as magnetic resonance imaging contrast agents, multimodal imaging and drug carriers. In order to perform these functions in medicine, shape and size control of the SPIONs is vital. We sampled SPIONs at ten-minutes intervals during the high-temperature thermal decomposition reaction. Their shape (sphericity and anisotropy) and geometric description (volume and surface area) were retrieved using three-dimensional imaging techniques, which allowed to reconstruct each particle in three dimensions, followed by stereological quantification methods. The results, supported by small angle X-ray scattering characterization, reveal that SPIONs initially have a spherical shape, then grow increasingly asymmetric and irregular. A high heterogeneity in volume at the initial stages makes place for lower particle volume dispersity at later stages. The SPIONs settled into a preferred orientation on the support used for transmission electron microscopy imaging, which hides the extent of their anisotropic nature in the axial dimension, there by biasing the interpretation of standard 2D micrographs. This information could be feedback into the design of the chemical processes and the characterization strategies to improve the current applications of SPIONs in nanomedicine.

Silver-coated zero-valent iron nanoparticles enhance cancer therapy in mice through lysosome-dependent dual programed cell death pathways: triggering simultaneous apoptosis and autophagy only in cancerous cells

In this study, we demonstrated that zero-valent iron (ZVI), which is widely used to remediate environmental contamination through the production of high-energy reactive oxygen species (ROS), exhibited differential cytotoxicity in cancerous cells and nonmalignant cells. Nanoparticles (NPs) with different shells exhibited distinct potencies against cancerous cells, which depended on their iron-to-oxygen ratios. Silver-coated ZVI NPs (ZVI@Ag) had the highest potency among synthesized ZVI NPs, and they simultaneously exhibited adequate biocompatibility with nonmalignant keratinocytes. The assessment of the intracellular dynamics of iron species revealed that the uptake of ZVI@Ag was similar between cancerous cells and nonmalignant cells during the first 2 h; however, only cancerous cells rapidly converted NPs into iron ions and generated large amounts of intracellular ROS, which was followed by apoptosis and autophagy induction. The aforementioned processes were prevented in the presence of iron ion chelators or by preoxidizing NPs before administration. Neutralization of lysosomal pH effectively reduced ZVI@Ag NP-induced programmed cell death. In the xenograft mouse model, cancer growth was significantly inhibited by a single dose of systematically administered NPs without significant weight loss in animals.

Protein and Polysaccharide-Based Magnetic Composite Materials for Medical Applications

The combination of protein and polysaccharides with magnetic materials has been implemented in biomedical applications for decades. Proteins such as silk, collagen, and elastin and polysaccharides such as chitosan, cellulose, and alginate have been heavily used in composite biomaterials. The wide diversity in the structure of the materials including their primary monomer/amino acid sequences allow for tunable properties. Various types of these composites are highly regarded due to their biocompatible, thermal, and mechanical properties while retaining their biological characteristics. This review provides information on protein and polysaccharide materials combined with magnetic elements in the biomedical space showcasing the materials used, fabrication methods, and their subsequent applications in biomedical research.

Doxorubicin/Cisplatin-Loaded Superparamagnetic Nanoparticles As A Stimuli-Responsive Co-Delivery System For Chemo-Photothermal Therapy

INTRODUCTION

To date, numerous iron-based nanostructures have been designed for cancer therapy applications. Although some of them were promising for clinical applications, few efforts have been made to maximize the therapeutic index of these carriers. Herein, PEGylated silica-coated iron oxide nanoparticles (PS-IONs) were introduced as multipurpose stimuli-responsive co-delivery nanocarriers for a combination of dual-drug chemotherapy and photothermal therapy.

METHODS

Superparamagnetic iron oxide nanoparticles were synthesized via the sonochemical method and coated by a thin layer of silica. The nanostructures were then further modified with a layer of di-carboxylate polyethylene glycol (6 kDa) and carboxylate-methoxy polyethylene glycol (6 kDa) to improve their stability, biocompatibility, and drug loading capability. Doxorubicin (DOX) and cisplatin (CDDP) were loaded on the PS-IONs through the interactions between the drug molecules and polyethylene glycol.

RESULTS

The PS-IONs demonstrated excellent cellular uptake, cytocompatibility, and hemocompatibility at the practical dosage. Furthermore, in addition to being an appropriate MRI agent, PS-IONs demonstrated superb photothermal property in 0.5 W/cm2 of 808 nm laser irradiation. The release of both drugs was effectively triggered by pH and NIR irradiation. As a result of the intracellular combination chemotherapy and 10 min of safe power laser irradiation, the highest cytotoxicity for iron-based nanocarriers (97.3±0.8%) was achieved.

CONCLUSION

The results of this study indicate the great potential of PS-IONs as a multifunctional targeted co-delivery system for cancer theranostic application and the advantage of employing proper combination therapy for cancer eradication.

3D Superparamagnetic Scaffolds for Bone Mineralization under Static Magnetic Field Stimulation

We reported on three-dimensional (3D) superparamagnetic scaffolds that enhanced the mineralization of magnetic nanoparticle-free osteoblast cells. The scaffolds were fabricated with submicronic resolution by laser direct writing via two photons polymerization of Ormocore/magnetic nanoparticles (MNPs) composites and possessed complex and reproducible architectures. MNPs with a diameter of 4.9 ± 1.5 nm and saturation magnetization of 30 emu/g were added to Ormocore, in concentrations of 0, 2 and 4 mg/mL. The homogenous distribution and the concentration of the MNPs from the unpolymerized Ormocore/MNPs composite were preserved after the photopolymerization process. The MNPs in the scaffolds retained their superparamagnetic behavior. The specific magnetizations of the scaffolds with 2 and 4 mg/mL MNPs concentrations were of 14 emu/g and 17 emu/g, respectively. The MNPs reduced the shrinkage of the structures from 80.2 ± 5.3% for scaffolds without MNPs to 20.7 ± 4.7% for scaffolds with 4 mg/mL MNPs. Osteoblast cells seeded on scaffolds exposed to static magnetic field of 1.3 T deformed the regular architecture of the scaffolds and evoked faster mineralization in comparison to unstimulated samples. Scaffolds deformation and extracellular matrix mineralization under static magnetic field (SMF) exposure increased with increasing MNPs concentration. The results are discussed in the frame of gradient magnetic fields of ~3 × 10⁻⁴ T/m generated by MNPs over the cells bodies.

Co-delivery of paclitaxel and curcumin to foliate positive cancer cells using Pluronic-coated iron oxide nanoparticles

Active targeting of folic acid and passive targeting of magnetic nanoparticles to bring about co-delivery of hydrophobic chemotherapeutic agents were the focus of this work. Co-precipitation in alkaline environment was employed for synthesizing Fe3O4 nanoparticles and stabilized by oleic acid. Aqueous dispersibility of oleic acid coated nanoparticles was brought about by folic acid modified Pluronic F127 and Pluronic F127 mixture. Folic acid is used as a targeting agent which was joined to Pluronic F127 via diethylene glycol bis(3-aminopropyl) ether spacer. The nanocomposite was used to delivery hydrophobic anticancer drugs, paclitaxel, and curcumin. Successful modification at each step was confirmed by FTIR and NMR. Quantitative analysis of attached folic acid indicated a total of 84.34% amount of conjugation. Nanoparticles characterization revealed the hydrodynamic size of and nanocomposite to be 94.2 nm nanometres. Furthermore, transmission electron micrograph reveals the size of the nanoparticle to be 12.5 nm hence also shows the superparamagnetic activity. Drug encapsulation efficiency of 34.7% and 59.5% was noted for paclitaxel and curcumin, respectively. Cytotoxic property of drug-loaded nanocomposites was increased in case of folic acid functionalized nanoparticles and further increased in the presence of an external magnetic field. Cellular uptake increased in the folic acid conjugated sample. Further many folds in the presence of an external magnetic field.

Nanostructured carriers as innovative tools for cancer diagnosis and therapy

Cancer accounts for millions of deaths every year and, due to the increase and aging of the world population, the number of new diagnosed cases is continuously rising. Although many progresses in early diagnosis and innovative therapeutic protocols have been already set in clinical practice, still a lot of critical aspects need to be addressed in order to efficiently treat cancer and to reduce several drawbacks caused by conventional therapies. Nanomedicine has emerged as a very promising approach to support both early diagnosis and effective therapy of tumors, and a plethora of different inorganic and organic multifunctional nanomaterials have been ad hoc designed to meet the constant demand for new solutions in cancer treatment. Given their unique features and extreme versatility, nanocarriers represent an innovative and easily adaptable tool both for imaging and targeted therapy purposes, in order to improve the specific delivery of drugs administered to cancer patients. The current review reports an in-depth analysis of the most recent research studies aiming at developing both inorganic and organic materials for nanomedical applications in cancer diagnosis and therapy. A detailed overview of different approaches currently undergoing clinical trials or already approved in clinical practice is provided.

Evaluation of in vitro cytotoxicity of superparamagnetic poly(thioether-ester) nanoparticles on erythrocytes, non-tumor (NIH3T3), tumor (HeLa) cells and hyperthermia studies

Magnetic nanoparticles encapsulated in biocompatible and biodegradable polymeric matrices are promising materials for biomedical applications, such as transport of antitumoral drugs and cancer treatment by hyperthermia. In this study, biobased poly(thioether-ester), PTEe, was obtained by thiol-ene polymerization and superparamagnetic nanoparticles, MNPs, were successfully incorporated in PTEe nanoparticles by miniemulsification followed by solvent evaporation. MNPs-PTEe nanoparticles with average diameter around 150 nm presented superparamagnetic behavior as confirmed by magnetization curves analysis. MNPs-PTEe nanoparticles did not present hemolytic damage on human red blood cells when incubated for 24 h. According to the cell viability assays, nanoparticles did not present any cytotoxic effect on murine fibroblast cell (NIH3T3) and human cervical cancer (HeLa). Hyperthermia assays were applied, demonstrating that AC magnetic field application (110 KHz-500 Oe) for 20 min significantly reduced the cells viability. The morphology evaluation of HeLa showed a hypoxia region one hour after hyperthermia application. Therefore, the results indicated that the superparamagnetic poly(thioether-ester) nanoparticles can be an excellent alternative for the targeted delivery of antitumor drugs and cancer treatment for hyperthermia.

Synergistic delivery of 5-fluorouracil and curcumin using human serum albumin-coated iron oxide nanoparticles by folic acid targeting

Human serum albumin is the most abundant protein in plasma with the ability to bind to a variety of drug molecules. Magnetic nanoparticles are being extensively used in drug delivery due to its intrinsic magnetic properties. In this work, we have synthesized human serum albumin-coated citrate-functionalized iron oxide nanoparticles by CDI coupling. Furthermore, folic acid was decorated on human serum albumin by EDC and NHS coupling to confer targetability. Two cytotoxic drugs 5-fluorouracil (5FU) and curcumin were co-delivered. Wherein, the former is an anticancer agent and latter is a drug resistance depressor of former. The nanoparticles showed good aqueous dispersibility with a zeta potential of - 49.1 mV and magnetic core size in the range of 10-15 nm, thus exhibiting good magnetic property with magnetic saturation of 33.59 emu/g. Controlled drug release behavior was noticed in both drugs with faster release profile of 5FU. Nanoparticles also showed good cytotoxicity with lower IC50 values in the presence of magnetic field. The contrasting difference was noticed in folic acid-decorated and non-decorated composites, similarly in the presence of magnetic field where cell uptake was enhanced.

Improved anticancer efficacy of epirubicin by magnetic mesoporous silica nanoparticles: in vitro and in vivo studies

The development of magnetic nanoparticles as delivery carriers to magnetically accumulate anticancer drug in cancer tissue has attracted immense interest. In the present study, magnetic mesoporous silica nanoparticles (MMSNs) with magnetite core and silica shell were synthesized. The obtained MMSNs were characterized by DLS, XRD, FT-IR, TEM and VSM in order to investigate the nanoparticle characteristics. With the focus on in vivo validation of such magnetic drug delivery systems, we selected epirubicin (EPI) as the drug. The anticancer properties of EPI-loaded MMSNs were evaluated in a C-26 colon carcinoma model. Alongside monitoring of drug in the tissues with animal imaging system, the tissue distribution was also determined quantitavely. The average size of MMSNs determined with TEM images was about 18.68 ± 2.31 nm. The cellular uptake test indicated that geometric mean fluorescence intensity (MFI) of cells treated with MMSN + EPI in presence of external magnetic field was increasing 27% compared with free EPI. In addition, treatment with drug-loaded MMSNs with the aid of external magnetic gradient had significantly higher inhibition efficacy towards tumor growth than the free EPI treated mice. The targeted drug delivery through external magnet-attraction using EPI-loaded MMSNs resulted in high tumor cell uptake, which leads to elimination of cancer cells effectively.

Preparation and Characterization of WS₂@SiO₂ and WS₂@PANI Core-Shell Nanocomposites

Two tungsten disulfide (WS₂)-based core-shell nanocomposites were fabricated using readily available reagents and simple procedures. The surface was pre-treated with a surfactant couple in a layer-by-layer approach, enabling good dispersion of the WS₂ nanostructures in aqueous media and providing a template for the polymerization of a silica (SiO₂) shell. After a Stöber-like reaction, a conformal silica coating was achieved. Inspired by the resulting nanocomposite, a second one was prepared by reacting the surfactant-modified WS₂ nanostructures with aniline and an oxidizing agent in an aqueous medium. Here too, a conformal coating of polyaniline (PANI) was obtained, giving a WS₂@PANI nanocomposite. Both nanocomposites were analyzed by electron microscopy, energy dispersive X-ray spectroscopy (EDS) and FTIR, verifying the core-shell structure and the character of shells. The silica shell was amorphous and mesoporous and the surface area of the composite increases with shell thickness. Polyaniline shells slightly differ in their morphologies dependent on the acid used in the polymerization process and are amorphous like the silica shell. Electron paramagnetic resonance (EPR) spectroscopy of the WS₂@PANI nanocomposite showed variation between bulk PANI and the PANI shell. These two nanocomposites have great potential to expand the use of transition metals dichalcogenides (TMDCs) for new applications in different fields.

Doxorubicin-loaded dendritic-Fe3O4 supramolecular nanoparticles for magnetic drug targeting and tumor regression in spheroid murine melanoma model

This work evaluates the magnetically-guided delivery of DOX-loaded dendritic-Fe₃O₄ nanoparticles and their tumor regression efficacy in subcutaneous melanoma in C57BL/6 mice. The hematological, biochemical and histopathological parameters were minimally affected. The nanoparticles localized in lungs, liver and spleen suggesting non-specific uptake. However, in tumor-bearing mice, substantially higher localization in magnetically-targeted tumor was observed when compared to passive localization in non-targeted tumor. The animals of treated group showed significantly high iron levels (161 μg of Fe/mg dry organ weight) in the tumor against the control (<25 μg of Fe/mg dry organ weight). This high localization led to high concentrations of DOX in the tumor which not only induced significant tumor regression but also arrested further growth. Within 14 days, the average tumor volume was reduced to 55±8.3 mm³ (treated) as compared to 4794±844 mm³ (control), i.e. ~88-fold decrease. The tumor disappeared by the end of 20^th day post-treatment and ~100% survival rate was observed.

Biocompatible coated magnetosome minerals with various organization and cellular interaction properties induce cytotoxicity towards RG-2 and GL-261 glioma cells in the presence of an alternating magnetic field

Background

Biologics magnetics nanoparticles, magnetosomes, attract attention because of their magnetic characteristics and potential applications. The aim of the present study was to develop and characterize novel magnetosomes, which were extracted from magnetotactic bacteria, purified to produce apyrogen magnetosome minerals, and then coated with Chitosan, Neridronate, or Polyethyleneimine. It yielded stable magnetosomes designated as M-Chi, M-Neri, and M-PEI, respectively. Nanoparticle biocompatibility was evaluated on mouse fibroblast cells (3T3), mouse glioblastoma cells (GL-261) and rat glioblastoma cells (RG-2). We also tested these nanoparticles for magnetic hyperthermia treatment of tumor in vitro on two tumor cell lines GL-261 and RG-2 under the application of an alternating magnetic field. Heating, efficacy and internalization properties were then evaluated.

Results

Nanoparticles coated with chitosan, polyethyleneimine and neridronate are apyrogen, biocompatible and stable in aqueous suspension. The presence of a thin coating in M-Chi and M-PEI favors an arrangement in chains of the magnetosomes, similar to that observed in magnetosomes directly extracted from magnetotactic bacteria, while the thick matrix embedding M-Neri leads to structures with an average thickness of 3.5 µm² per magnetosome mineral. In the presence of GL-261 cells and upon the application of an alternating magnetic field, M-PEI and M-Chi lead to the highest specific absorption rates of 120–125 W/g_Fe. Furthermore, while M-Chi lead to rather low rates of cellular internalization, M-PEI strongly associate to cells, a property modulated by the application of an alternating magnetic field.

Conclusions

Coating of purified magnetosome minerals can therefore be chosen to control the interactions of nanoparticles with cells, organization of the minerals, as well as heating and cytotoxicity properties, which are important parameters to be considered in the design of a magnetic hyperthermia treatment of tumor.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-017-0293-2) contains supplementary material, which is available to authorized users.

Evaluation of Tumor Treatment of Magnetic Nanoparticles Driven by Extremely Low Frequency Magnetic Field

Recently, magnetic nanoparticles (MNPs), which can be manipulated in the magnetic field, have received much attention in tumor therapy. Extremely low frequency magnetic field (ELMF) system can initiate MNPs vibrating and the movement of MNPs inside of cells can be controlled by adjusting the frequency and intensity of ELMF towards irreversible cell damages. In this study, we investigated the detrimental effects on tumor cells with MNPs under various ELMF exposure conditions. An in-house built ELMF system was developed and utilized for evaluating the treatment efficiency of MNPs on tumor cells with specific intensities (2–20 Hz) and frequencies (0.1–20 mT). Significant morphological changes were found in tumor cells treated with MNPs in combing with ELMF, which were consistent with noticeable decrease in cell viability. With the increase of the intensity and frequency of the magnetic field, the structural integrity of tumor tissue can be further destroyed. Destructive effects of MNPs and ELMF on tumor tissues were further determined by the pathophysiological changes observed in vivo in animal study. Taken together, the combination of MNPs and ELMF had a great potential as an innovative treatment approach for tumor intervention.

The Effect of Co0.2Mn0.8Fe2O4 Ferrite Nanoparticles on the C2 Canine Mastocytoma Cell Line and Adipose-Derived Mesenchymal Stromal Stem Cells (ASCs) Cultured Under a Static Magnetic Field: Possible Implications in the Treatment of Dog Mastocytoma

Cobalt manganese ferrite nanoparticles have application potential in the biomedical field, however there is limited information concerning the biological response. The aim of this work was to investigate the cytotoxic potential of cobalt-manganese ferrite nanoparticles in canine mastocytoma tumor cells (C2) and adipose-derived mesenchymal stromal stem cells (ASCs) cultured under a static magnetic field (MF). In this study, we investigated the viability and proliferation rate of ASC and C2 cells cultured with Co0.2Mn0.8Fe2O4 nanoparticles under 0.5T MF. We observed cells morphology and measured intracellular ROS generation. Thermal observations were used to characterize the thermotrophic cell behavior in different condition and RNA level of heat shock proteins and apoptotic genes was measured. Nanoparticles reduced cell viability, caused cell damage, i.e., through the formation of reactive oxygen species (ROS) and increased transcriptional level of apoptotic genes (Bcl-2, Bax, p53, p21). In addition, we have found that C2 mastocytoma cells cultured with metal oxide nanoparticles under MF exhibited unexpected biological responses, including thermotolerance and apoptotic response induced by the expression of heat shock proteins and ROS produced under a MF. Our results suggest that stimulation using MF and Co0.2Mn0.8Fe2O4 nanoparticles is involved in mechanisms associated with controlling cell proliferative potential signaling events. We can state that significant differences between normal and cancer cells in response to nanoparticles and MF are apparent. Our results show that nanoparticles and MF elevate the temperature in vitro in tumor cells, thereby increasing the expression of ROS as well as heat shock proteins.

Magnetic Characterization of Iron Oxide Nanoparticles for Biomedical Applications

Iron oxide nanoparticles are of interest in a wide range of biomedical applications due to their response to applied magnetic fields and their unique magnetic properties. Magnetization measurements in constant and time-varying magnetic field are often carried out to quantify key properties of iron oxide nanoparticles. This chapter describes the importance of thorough magnetic characterization of iron oxide nanoparticles intended for use in biomedical applications. A basic introduction to relevant magnetic properties of iron oxide nanoparticles is given, followed by protocols and conditions used for measurement of magnetic properties, along with examples of data obtained from each measurement, and methods of data analysis.

Synthesis, characterization and in vivo evaluation of a magnetic cisplatin delivery nanosystem based on PMAA-graft-PEG copolymers

The development of anticancer drug delivery systems which retain or enhance the cytotoxic properties of the drug to tumorous tissues, while reducing toxicity to other organs is of key importance. We investigated different poly(methacrylic acid)-g-poly(ethyleneglycol methacrylate) polymers as in situ coating agents for magnetite nanocrystallites. The obtained magnetic nano-assemblies were in turn thoroughly characterized for their structural, colloidal and physicochemical properties (drug loading capacity/release, magnetic field triggered drug release, cell uptake and localization) in order to select the best performing system. With the focus on in vivo validation of such magnetic drug delivery systems for first time, we selected cisplatin as the drug, since it is a potent anticancer agent which exhibits serious side effects due to lack of selectivity. In addition, cisplatin would offer facile determination of the metal content in the animal tissues for biodistribution studies. Alongside post-mortem Pt determination in the tissues, the biodistribution of the drug nanocarriers was also monitored in real time with PET-CT (positron emission tomography/computed tomography) with and without the presence of magnetic field gradients; using a novel chelator-free method, the nanoparticles were radiolabeled with ⁶⁸Ga without having to alter their structure with chemical modifications for conjugation of radiochelators. The ability to be radiolabeled in such a straightforward but very robust way, along with their measured high MRI response, renders them attractive for dual imaging, which is an important functionality for translational investigations. Their anticancer properties were evaluated in vitro and in vivo, in a cisplatin resistant HT-29 human colon adenocarcinoma model, with and without the presence of magnetic field gradients. Enhanced anticancer efficacy and reduced toxicity was recorded for the cisplatin-loaded nanocarriers in comparison to the free cisplatin, particularly when a magnetic field gradient was applied at the tumor site. Post mortem and real-time tissue distribution studies did not reveal increased cisplatin concentration in the tumor site, suggesting that the enhanced anticancer efficacy of the cisplatin-loaded nanocarriers is driven by mechanisms other than increased cisplatin accumulation in the tumors.