Biocompatible mesoporous silica-coated superparamagnetic manganese ferrite nanoparticles for targeted drug delivery and MR imaging applications

Magnetic nanoparticles and possible synergies with cold atmospheric plasma for cancer treatment

The biomedical applications of magnetic nanoparticles (MNPs) have gained increasing attention due to their unique biological, chemical, and magnetic properties such as biocompatibility, chemical stability, and high magnetic susceptibility. However, several critical issues still remain that have significantly halted the clinical translation of these nanomaterials such as the relatively low therapeutic efficacy, hyperthermia resistance, and biosafety concerns. To identify innovative approaches possibly creating synergies with MNPs to resolve or mitigate these problems, we delineated the anti-cancer properties of MNPs and their existing onco-therapeutic portfolios, based on which we proposed cold atmospheric plasma (CAP) to be a possible synergizer of MNPs by enhancing free radical generation, reducing hyperthermia resistance, preventing MNP aggregation, and functioning as an innovative magnetic and light source for magnetothermal- and photo-therapies. Our insights on the possible facilitating role of CAP in translating MNPs for biomedical use may inspire fresh research directions that, once actualized, gain mutual benefits from both.

Amine-functionalized mesoporous silica nanoparticles decorated by silver nanoparticles for delivery of doxorubicin in breast and cervical cancer cells

Nanocarriers have demonstrated promising potential in the delivery of various anticancer drugs and in improving the efficiency of the treatment. In this study, silver nanoparticles (AgNPs) were green-synthesized using the extracts of different parts of the pomegranate plant, including the peel, flower petals, and calyx. To obtain the most efficient extract used for the green synthesis of AgNPs, all three types of synthesized nanoparticles were characterized. Then, (3-Aminopropyl) triethoxysilane-functionalized mesoporous silica nanoparticles (MSNs-APTES) decorated with AgNPs were fabricated via a one-pot green-synthesis method. AgNPs were directly coated on the surface of MSNs-APTES by adding pomegranate extract enriched with a source of reducing agent leading to converting the silver ion to AgNPs. The MSN-APTES-AgNPs (MSNs-AgNPs) have been thoroughly characterized using nanoparticle characterization techniques. In addition, DNA cleavage and hemolysis activities of the synthesized nanoparticles were analyzed, confirming the biocompatibility of synthesized nanoparticles. The Doxorubicin (DOX, as a breast/cervical anti-cancer drug) loading (42.8%) and release profiles were investigated via UV-visible spectroscopy. The fibroblast, breast cancer, and cervical cancer cells' viability against DOX-loaded nanoparticles were also studied. The results of this high drug loading, uniform shape, and small functionalized nanoparticles demonstrated its great potential for breast and cervical cancer management.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Design of manganese-based nanomaterials for pharmaceutical and biomedical applications

In the past few years, manganese-based nanostructures have been extensively investigated in the biomedical field particularly to design highly biocompatible theranostics, which can not only act as efficient diagnostic imaging contrast agents but also deliver the drugs to the target sites. The nanoscale size, large surface area-to-volume ratio, availability of cheap precursors, flexibility to synthesize nanostructures with reproducible properties and high yield, and easy scale up are the major reasons for the attraction towards manganese nanostructures. Along with these properties, the nontoxic nature, pH-sensitive degradation, and easy surface functionalization are additional benefits for the use of manganese nanostructures in biomedical and pharmaceutical sciences. Therefore, in this review, we discuss the recent progress made in the synthesis of manganese nanostructures, describe the attempts made to modify their surfaces to impart biocompatibility and stability in biological fluids, and critically discuss their use in magnetic resonance imaging, drug and gene delivery, hyperthermia, photothermal/photodynamic, immunotherapy, biosensing and tumor diagnosis.

Toxicity evaluation of silica nanoparticles for delivery applications

Silica nanoparticles (SiNPs) are being explored as nanocarriers for therapeutics delivery, which can address a number of intrinsic drawbacks of therapeutics. To translate laboratory innovation into clinical application, their potential toxicity has been of great concern. This review attempts to comprehensively summarize the existing literature on the toxicity assessment of SiNPs. The current data suggest that the composition of SiNPs, their physicochemical properties, their administration route, their frequency and duration of administration, and the sex of animal models are related to their tissue and blood toxicity, immunotoxicity, and genotoxicity. However, the correlation between in vitro and in vivo toxicity has not been well established, mainly because both the in vitro and the in vivo-dosed quantities are unrealistic. This article also discusses important factors to consider in the toxicology of SiNPs and current approaches to reducing their toxicity. The aim is to give readers a better understanding of the toxicology of silica nanoparticles and to help identify key gaps in knowledge and techniques.

pH-Dependent Behavior of Novel 5-FU Delivery System in Environmental Conditions Comparable to the Gastro-Intestinal Tract

A biogenic carrier for 5-fluorouracil (5-FU) loading and subsequent tableting as a new drug formulation for slow release has been proposed using the biomineral from blue crab carapace. Due to its highly ordered 3D porous nanoarchitecture, the biogenic carbonate carrier could achieve increased effectiveness in colorectal cancer cure provided that the formulation would successfully pass through the gastric acid conditions. Following the recently proven viability of the concept by demonstrating the slow release of the drug from the carrier using the highly sensitive SERS technique, here we investigated the 5-FU release from the composite tablet drug in pH conditions replicating the gastric environment. The released drug from the tablet was studied in solutions with three relevant pH values, pH 2, pH 3, and pH 4. The 5-FU SERS spectral signature for each pH value was used to build calibration curves for quantitative SERS analysis. The results suggested a similarly slow-releasing pattern in acid pH environments to that in neutral conditions. Although biogenic calcite dissolution was expected in acid conditions, the X-ray diffraction and Raman spectroscopy showed preservation of calcite mineral along with the monohydrocalcite during acid solution exposure for two hours. The total released amount in a time course of seven hours, however, was lower in acidic pH solutions, with a maximum fraction of ~40% of the total amount of loaded drug, for pH 2, as opposed to ~80% for neutral values. Nonetheless, these results clearly prove that the novel composite drug retains its slow-releasing character in environmental conditions compatible with the gastrointestinal pH and that it is a viable and biocompatible alternative for oral delivery of anticancer drug to reach the lower gastro-intestinal tract.

Synthesis and characterization of a smart polymer-coated core–shell MnFe2O4@ organometallic framework for targeted drug delivery

Scientists are currently working to develop more effective and less harmful methods of delivering drugs to tissue. One method is to use a special type of carrier to help the drug get to the right place in the body. In this study, an organometallic framework nanocarrier with the formula IRMOF-3 [Zn4O(NH2-BDC)3] was successfully prepared, containing magnetic nanoparticles of manganese ferrite (MnFe2O4) and the drug doxorubicin encapsulated in a pH- and temperature-sensitive smart polymer of poly-N-isopropylacrylamide. Doxorubicin, an anticancer drug, was loaded into the pores of a magnetic organometallic framework and modified with the smart polymer poly(N-isopropylacrylamide-co-AA), which has a lower critical solution temperature (LCST) of less than 38 °C. The synthesis of magnetic nanoparticles and magnetic organometallic frameworks encapsulated in smart polymer was investigated using various analytical techniques such as Fourier transform infrared spectrometer, thermal stability analysis, BET, and VSM. The particles in the synthesized nanocarrier are uniform in size, have high magnetic properties, and are thermally stable. The effective surface area is 7.26 m2/g, and the pore volume is 166.394 m. The drug carrier has the ability to load up to 78% of the drug into the solution. The highest drug release was observed when the pH was 5 and the temperature was higher than the LCST. 71% of cancer cells were destroyed by the drug carrier in the culture medium. This nanosystem, designed with more drug retention, reduced side effects and controlled release in different conditions, is suitable as a drug delivery system.

Engineering 2D Aligned Nanowires Assembled Porous Hetero-Membrane for Smart Ion Transport

Engineering 2D nanosheets with well-defined porous structures and their assembled heterostructure membrane is a promising method to improve osmotic energy conversion. However, it is still a great challenge to directly fabricate 2D nanosheets with regular parallel nanochannels in aqueous media. Here, the desired functional nanosheets and heterostructure membrane device are successfully prepared through a simple interfacial assembly strategy. In this method, monolayer cylindrical monomicelles closely arrange and assemble on the surfaces of graphene oxide, and the resulting nanosheets with monolayered aligned nanowire polymer arrays parallel to the substrate surfaces are then obtained. Subsequently, a heterostructured membrane is constructed by assembling these 2D nanosheets on macroporous alumina. The nanofluidic membrane device with asymmetric geometry and charge polarity exhibits smart ion transport properties, and the output osmotic power density is ≈1.22 and 1.63 times over the reported pure 2D graphene oxide and biomass-derived membranes, respectively. In addition, theoretical calculations are carried out to reveal the mechanisms for ion selectivity and salinity gradient energy conversion. This monolayered interfacial assembly approach can open up new avenues for the synthesis of functional porous low-dimensional nanomaterials and membrane devices, and expand the palette of materials selection for many applications.

Insights of Platinum Drug Interaction with Spinel Magnetic Nanocomposites for Targeted Anti-Cancer Effect

In nanotherapeutics, gaining insight about the drug interaction with the pore architecture and surface functional groups of nanocarriers is crucial to aid in the development of targeted drug delivery. Manganese ferrite impregnated graphene oxide (MnFe₂O₄/GO) with a two-dimensional sheet and spherical silica with a three-dimensional interconnected porous structure (MnFe₂O₄/silica) were evaluated for cisplatin release and cytotoxic effects. Characterization studies revealed the presence of Mn²⁺ species with a variable spinel cubic phase and superparamagnetic effect. We used first principles calculations to study the physisorption of cisplatin on monodispersed silica and on single- and multi-layered GO. The binding energy of cisplatin on silica and single-layer GO was ~1.5 eV, while it was about double that value for the multilayer GO structure. Moreover, we treated MCF-7 (breast cancer cells) and HFF-1 (human foreskin fibroblast) with our nanocomposites and used the cell viability assay MTT. Both nanocomposites significantly reduced the cell viability. Pt⁴⁺ species of cisplatin on the spinel ferrite/silica nanocomposite had a better effect on the cytotoxic capability when compared to GO. The EC50 for MnFe₂O₄/silica/cisplatin and MnFe₂O₄/GO/cisplatin on MCF-7 was: 48.43 µg/mL and 85.36 µg/mL, respectively. The EC50 for the same conditions on HFF was: 102.92 µg/mL and 102.21 µg/mL, respectively. In addition, immunofluorescence images using c-caspase 3/7, and TEM analysis indicated that treating cells with these nanocomposites resulted in apoptosis as the major mechanism of cell death.

Synthesis and Cytotoxicity Assessment of Citrate-Coated Calcium and Manganese Ferrite Nanoparticles for Magnetic Hyperthermia

Calcium-doped manganese ferrite nanoparticles (NPs) are gaining special interest in the biomedical field due to their lower cytotoxicity compared with other ferrites, and the fact that they have improved magnetic properties. Magnetic hyperthermia (MH) is an alternative cancer treatment, in which magnetic nanoparticles promote local heating that can lead to the apoptosis of cancer cells. In this work, manganese/calcium ferrite NPs coated with citrate (Ca_xMn_1-xFe₂O₄ (x = 0, 0.2, 1), were synthesized by the sol-gel method, followed by calcination, and then characterized regarding their crystalline structure (by X-ray diffraction, XRD), size and shape (by Transmission Electron Microscopy, TEM), hydrodynamic size and zeta potential (by Dynamic Light Scattering, DLS), and heating efficiency (measuring the Specific Absorption Rate, SAR, and Intrinsic Loss Power, ILP) under an alternating magnetic field. The obtained NPs showed a particle size within the range of 10 nm to 20 nm (by TEM) with a spherical or cubic shape. Ca_0.2Mn_0.8Fe₂O₄ NPs exhibited the highest SAR value of 36.3 W/g at the lowest field frequency tested, and achieved a temperature variation of ~7 °C in 120 s, meaning that these NPs are suitable magnetic hyperthermia agents. In vitro cellular internalization and cytotoxicity experiments, performed using the human cell line HEK 293T, confirmed cytocompatibility over 0-250 µg/mL range and successful internalization after 24 h. Based on these studies, our data suggest that these manganese-calcium ferrite NPs have potential for MH application and further use in in vivo systems.

Precise dapagliflozin delivery by cardiac homing peptide functionalized mesoporous silica nanocarries for heart failure repair after myocardial infarction

Myocardial infarction (MI) may cause irreversible damage or destroy to part of the heart muscle, affecting the heart’s ability and power to pump blood as efficiently as before, often resulting in heart failure (HF). Cardiomyocyte death and scar formation after MI may then trigger chronic neurohormonal activation and ventricular remodeling. We developed a biocompatible and mono-dispersed mesoporous silica nanoparticles (MSN) divergent porous channel for dapagliflozin (DAPA) loading. After surface modification of the cardiac-targeting peptides, the novel drug delivery system was successfully homed, and precisely released drugs for the hypoxic and weak acid damaged cardiomyocytes. Our biocompatible MSN- based nanocarriers for dapagliflozin delivery system could effective cardiac repair and regeneration in vivo, opening new opportunities for healing patients with ischemic heart disease in clinical.

H2O2/pH Dual-Responsive Biomimetic Nanoenzyme Drugs Delivery System for Enhanced Tumor Photodynamic Therapy

Phototherapy has been recognized as a photochemical process to treat tumor via induce cancer cells necrosis and death, with minimal invasiveness, higher selectivity, and few side effects. However, the therapy effects of phototherapy are often compromised by the hypoxia, high levels of hydrogen peroxide, and glutathione of tumor microenvironment (TME). Therefore, we constructed a catalase-like activity bionic metal-organic framework drugs delivery system (FA-EM@MnO₂/ZIF-8/ICG) with tumor microenvironment controllable releasing. In this system, photosensitizer indocyanine green (ICG) was introduced into zeolite imidazole salt skeleton 8 (ZIF-8) by one-step methods, forming ZIF-8/ICG nano-platform, which can effectively avoid ICG-induced phototoxicity and aggregation-induced quenching during transport. MnO₂ with catalase-like activity was coated on the surface of ZIF-8/ICG nano-platform, which made it have the ability of self-supplying O₂ under the condition of H₂O₂ in TME. Exposure under near-infrared light can alleviate the anoxic TME, thus improving the phototherapy efficiency. In addition, folate-functionalized erythrocyte membrane is coated on the surface of MnO₂/ZIF-8/ICG, which can endow FA-EM@MnO₂/ZIF-8/ICG with the ability of targeted drug administration and immune elimination avoidance. Therefore, FA-EM@MnO₂/ZIF-8/ICG nano-platform has the catalase-like activity, which can alleviate the oxidative stress state of TME and provide a beneficial environment for photodynamic therapy of tumor.

A guide to the design of magnetic particle imaging tracers for biomedical applications

Magnetic Particle Imaging (MPI) is a novel and emerging non-invasive technique that promises to deliver high quality images, no radiation, high depth penetration and nearly no background from tissues. Signal intensity and spatial resolution in MPI are heavily dependent on the properties of tracers. Hence the selection of these nanoparticles for various applications in MPI must be carefully considered to achieve optimum results. In this review, we will provide an overview of the principle of MPI and the key criteria that are required for tracers in order to generate the best signals. Nanoparticle materials such as magnetite, metal ferrites, maghemite, zero valent iron@iron oxide core@shell, iron carbide and iron-cobalt alloy nanoparticles will be discussed as well as their synthetic pathways. Since surface modifications play an important role in enabling the use of these tracers for biomedical applications, coating options including the transfer from organic to inorganic media will also be discussed. Finally, we will discuss different biomedical applications and provide our insights into the most suitable tracer for each of these applications.

Synthesis of superparamagnetic MnFe2O4/mSiO2 nanomaterial for degradation of perfluorooctanoic acid by activated persulfate

In this paper, magnetic MnFe₂O₄/mSiO₂ nanocomposites were successfully synthesized, and the activation performance of the materials for persulfate was evaluated by the degradation efficiency of perfluorooctanoic acid. The structure of the catalyst was proved to be a core-shell structure by several characterization methods. The mesoporous silicon coating can effectively avoid the agglomeration of MnFe₂O₄ and at the same time increase the contact area with the reactants. A comparison of different catalyst addition conditions demonstrates that MnFe₂O₄/mSiO₂ can effectively activate the persulfate. The optimal reaction conditions were investigated by several key influencing factors. It was experimentally demonstrated that about 90% of PFOA (10 mg·L^-1) could be decomposed under the conditions of 0.4 g·L^-1 MnFe₂O₄/mSiO₂ and PS, pH 5.68, and 25 °C within 4 h; the defluorination rate reached 58.33%. In addition, the cyclability and stability tests demonstrated that MnFe₂O₄/mSiO₂ is a stable material that can be recycled. Furthermore, XPS characterization and radical scavenging experiments demonstrated that sulfate radicals (SO₄·^-) and hydroxyl radicals (OH) play a major role in the reaction of MnFe₂O₄/mSiO₂ activated PS. Subsequently, the degradation products were detected by high-performance liquid chromatography tandem triple quadrupole mass spectrometry, indicating that the degradation of PFOA is a gradual process of defluorination and decarbonization in the presence of free radicals. Finally, the metal leaching rate is tested to prove that the material meets environmental requirements while reacting efficiently. In conclusion, this study shows that MnFe₂O₄/mSiO₂ is an easily recoverable and highly efficient and stable material that has great potential for PS activation to treat organic pollutants in water.

A zinc ferrite nanodrug carrier for delivery of docetaxel: Synthesis, characterization and in vitro tests on C6 glioma cells

AIM

Docetaxel (DTX) loaded bio-compatible PLGA-PEG encapsulated zinc ferrite nanoparticles (ZFNP) formulation was developed and evaluated against C6 glioma cells.

METHODS

The ZFNP were characterized using XRD, FE-SEM, TEM etc. A series of drug formulations were fabricated by conjugating hydrothermally synthesized ZFNP with DTX in a PLGA-PEG matrix and optimized for drug loading. FTIR and DLS analysis of the formulation along with in vitro drug release, cytotoxicity, cellular uptake and haemolytic effect were evaluated.

RESULTS

Spherical, monodisperse, crystalline ZFNP with an average size of ∼28 nm were formed. The optimized formulation showed hydrodynamic diameter of ∼147 nm, surface charge of -34.8 mV, a drug loading of 6.9% (w/w) with prolonged drug release property and higher toxicity in C6 glioma cells compared to free DTX along with good internalization and negligible hemolysis.

CONCLUSION

The results indicate ZFNP could be effectively used as nanodrug carrier for delivery of docetaxel to glioma cells.

Enhanced Visible-Light Absorption of Fe2O3 Covered by Activated Carbon for Multifunctional Purposes: Tuning the Structural, Electronic, Optical, and Magnetic Properties

Visible-light absorption is a critical factor for photocatalyst activity and absorption of electromagnetic (EM) interference application. The band gap of Fe2O3 is 2 eV, which can be increased by doping with a high-band-gap material such as carbon from activated carbon (AC) with a band gap of 4.5 eV for increased visible-light absorption. The porosity decreases from 88 to 81.6%, and the band gap increases from 2.14 to 2.64 eV by increasing the AC from 10 to 25%, respectively. The photocatalytic activity takes 120 min to produce a harmless product for 10-20% AC, but 25% AC shows 89.5% degradation in only 90 min and the potential to attenuate the EM wave up to 99% due to the RL being below -20 dB. The second- and third-cycle degradation achieved by the composite Fe2O3-AC having 25% AC is 88.2 and 86.5% in 90 min, respectively. The pore of the surface state of AC contains a trapped charge, and interaction occurs between the charge (electron/hole) and O2 or H2O to produce OH and superoxide (O2 -) radicals. These radicals move inside the molecule of the pollutant (methylene blue (MB)) to break up the bond, with the final products being H2O and CO2. The X-ray photoelectron (XPS) spectra show that oxygen plays a key role in the interatomic bonding with Fe, C, and MB atoms. The best absorption of EM interference is -21.43 dB, with degradation reaching 89.51% in only 90 min for 25% AC due to its higher band gap and anisotropy constant. Fe2O3-carbon is a multifunctional material for the green environment because of its electromagnetic interference absorption and photodegradation of wastewater.

Improving anti-cancer drug delivery performance of magnetic mesoporous silica nanocarriers for more efficient colorectal cancer therapy

BACKGROUND

Improving anti-cancer drug delivery performance can be achieved through designing smart and targeted drug delivery systems (DDSs). For this aim, it is important to evaluate overexpressed biomarkers in the tumor microenvironment (TME) for optimizing DDSs.

MATERIALS AND METHODS

Herein, we designed a novel DDS based on magnetic mesoporous silica core-shell nanoparticles (SPION@MSNs) in which release of doxorubicin (DOX) at the physiologic pH was blocked with gold gatekeepers. In this platform, we conjugated heterofunctional polyethylene glycol (PEG) onto the outer surface of nanocarriers to increase their biocompatibility. At the final stage, an epithelial cell adhesion molecule (EpCAM) aptamer as an active targeting moiety was covalently attached (Apt-PEG-Au@NPs-DOX) for selective drug delivery to colorectal cancer (CRC) cells. The physicochemical properties of non-targeted and targeted nanocarriers were fully characterized. The anti-cancer activity, cellular internalization, and then the cell death mechanism of prepared nanocarriers were determined and compared in vitro. Finally, tumor inhibitory effects, biodistribution and possible side effects of the nanocarriers were evaluated in immunocompromised C57BL/6 mice bearing human HT-29 tumors.

RESULTS

Nanocarriers were successfully synthesized with a mean final size diameter of 58.22 ± 8.54 nm. Higher cytotoxicity and cellular uptake of targeted nanocarriers were shown in the EpCAM-positive HT-29 cells as compared to the EpCAM-negative CHO cells, indicating the efficacy of aptamer as a targeting agent. In vivo results in a humanized mouse model showed that targeted nanocarriers could effectively increase DOX accumulation in the tumor site, inhibit tumor growth, and reduce the adverse side effects.

CONCLUSION

These results suggest that corporation of a magnetic core, gold gatekeeper, PEG and aptamer can strongly improve drug delivery performance and provide a theranostic DDS for efficient CRC therapy.

Interfacial Super-Assembly of Ordered Mesoporous Carbon-Silica/AAO Hybrid Membrane with Enhanced Permselectivity for Temperature- and pH-Sensitive Smart Ion Transport

Nanofluidic devices have been widely used for diode-like ion transport and salinity gradients energy conversion. Emerging reverse electrodialysis (RED) nanofluidic systems based on nanochannel membrane display great superiority in salinity gradient energy harvesting. However, the imbalance between permeability and selectivity limits their practical application. Here, a new mesoporous carbon-silica/anodized aluminum (MCS/AAO) nanofluidic device with enhanced permselectivity for temperature- and pH-regulated energy generation was obtained by interfacial super-assembly method. A maximum power density of 5.04 W m^-2 is achieved, and a higher performance can be obtained by regulating temperature and pH. Theoretical calculations are further implemented to reveal the mechanism for ion rectification, ion selectivity and energy conversion. Results show that the MCS/AAO hybrid membrane has great superiority in diode-like ion transport, temperature- and pH-regulated salinity gradient energy conversion.

Folate receptor-mediated delivery of 1-MDT-loaded mesoporous silica magnetic nanoparticles to target breast cancer cells

Aims: The efficiency of mesoporous silica magnetic nanoparticles (MSMNP) as a targeted drug-delivery system was investigated. Methods: The superparamagnetic iron oxide nanoparticles (NP) were synthesized, coated with mesoporous silica and conjugated with polyethylene glycol and methotrexate. Next, 1-methyl-D-tryptophan was loaded into the prepared nanosystems (NS). They were characterized using transmission electron microscopy, scanning electron microscopy, dynamic light scattering, vibrating sample magnetometer, x-ray powder diffraction, Fourier transform-infrared spectroscopy and the Brunauer-Emmett-Teller method and their biological impacts on breast cancer cells were evaluated. Results: The prepared NSs displayed suitable properties and showed enhanced internalization by folate-receptor-expressing cells, exerting efficient cytotoxicity, which was further enhanced by the near-infrared radiation irradiation. Conclusion: On the basis of our findings, the engineered NS is a promising multifunctional nanomedicine/theranostic for solid tumors.

Sustainable Ethanol Production From Sugarcane Molasses by Saccharomyces cerevisiae Immobilized on Chitosan-Coated Manganese Ferrite

The interaction between nanostructures and yeast cells, as well as the description of the effect of nanoparticles in ethanol production are open questions in the development of this nanobiotechnological process. The objective of the present study was to evaluate the ethanol production by Saccharomyces cerevisiae in the free and immobilized state on chitosan-coated manganese ferrite, using cane molasses as a carbon source. To obtain the chitosan-coated manganese ferrite, the one-step coprecipitation method was used. The nanoparticles were characterized by X-ray diffraction obtaining the typical diffraction pattern. The crystal size was calculated by the Scherrer equation as 15.2 nm. The kinetics of sugar consumption and ethanol production were evaluated by HPLC. With the immobilized system, it was possible to obtain an ethanol concentration of 56.15 g/L, as well as the total sugar consumption at 24 h of fermentation. Productivity and yield in this case were 2.3 ± 0.2 g/(L * h) and 0.28 ± 0.03, respectively. However, at the same time in the fermentation with free yeast, 39.1 g/L were obtained. The total consumption of fermentable sugar was observed only after 42 h, reaching an ethanol titer of 50.7 ± 3.1, productivity and yield of 1.4 ± 0.3 g/(L * h) and 0.25 ± 0.4, respectively. Therefore, a reduction in fermentation time, higher ethanol titer and productivity were demonstrated in the presence of nanoparticles. The application of manganese ferrite nanoparticles shows a beneficial effect on ethanol production. Research focused on the task of defining the mechanism of their action and evaluation of the reuse of biomass immobilized on manganese ferrite in the ethanol production process should be carried out in the future.

Recent Advances in the Use of Iron-Gold Hybrid Nanoparticles for Biomedical Applications

Recently, there has been an increased interest in iron-gold-based hybrid nanostructures, due to their combined outstanding optical and magnetic properties resulting from the usage of two separate metals. The synthesis of these nanoparticles involves thermal decomposition and modification of their surfaces using a variety of different methods, which are discussed in this review. In addition, different forms such as core-shell, dumbbell, flower, octahedral, star, rod, and Janus-shaped hybrids are discussed, and their unique properties are highlighted. Studies on combining optical response in the near-infrared window and magnetic properties of iron-gold-based hybrid nanoparticles as multifunctional nanoprobes for drug delivery, magnetic-photothermal heating as well as contrast agents during magnetic and optical imaging and magnetically-assisted optical biosensing to detect traces of targeted analytes inside the body has been reviewed.

Emerging Biomedical Applications Based on the Response of Magnetic Nanoparticles to Time-Varying Magnetic Fields

Magnetic nanoparticles are of interest for biomedical applications because of their biocompatibility, tunable surface chemistry, and actuation using applied magnetic fields. Magnetic nanoparticles respond to time-varying magnetic fields via physical particle rotation or internal dipole reorientation, which can result in signal generation or conversion of magnetic energy to heat. This dynamic magnetization response enables their use as tracers in magnetic particle imaging (MPI), an emerging biomedical imaging modality in which signal is quantitative of tracer mass and there is no tissue background signal or signal attenuation. Conversion of magnetic energy to heat motivates use in nanoscale thermal cancer therapy, magnetic actuation of drug release, and rapid rewarming of cryopreserved organs. This review introduces basic concepts of magnetic nanoparticle response to time-varying magnetic fields and presents recent advances in the field, with an emphasis on MPI and conversion of magnetic energy to heat.

Metabolic Conversion and Removal of Manganese Ferrite Nanoparticles in RAW264.7 Cells and Induced Alteration of Metal Transporter Gene Expression

Background

Manganese Ferrite Nanoparticles (Mn-IONPs) are widely used in biomedical field and their cytotoxicity has been initially explored, but the mechanism remains obscure. The nano-bio interactions are believed to be crucial for cytotoxicity mechanism, while little data have been acquired.

Methods

Mn-IONPs were synthesized by thermal decomposition of acetylacetonate precursor. After physicochemical characterization, we analyzed the metabolic conversion and removal of Mn-IONPs in RAW264.7 cells by Prussian blue staining, TEM, HRTEM and elemental quantitative analysis, followed by gene expression evaluation using quantitative RT-PCR.

Results

Mn-IONPs were successfully synthesized. Both the uptake and cytotoxicity of Mn-IONPs on RAW264.7 cells were time- and dose-dependent. After internalized, Mn-IONPs were passed to daughter cells with passages on. Meanwhile, Mn-IONPs were exocytosed and digested to metal ions and further excreted out, resulted in the labeling rate and ions contents decreased gradually. As ion influx related genes, the expressions of ZIP14, IRP2, FtH and DMT1 were suppressed within 24 hours but overexpressed to a plateau at the 48th hour in a dose-dependent manner. At the 72nd hour, ZIP14 and DMT1 mRNA levels decreased toward normal, while IRP2 and FtH kept up-regulated. As efflux related genes, FPN, SLC30A10 and Hamp2 genes were up-regulated within 24–72 hours; SPCA1 was suppressed at the 24th and 72nd hour, while overexpressed at the 48th hour. All the efflux related genes’ mRNA had a dose-dependent increasing manner at the corresponding time points.

Conclusion

Mn-IONPs showed time- and dose-dependent cytotoxicity and cell labeling rate in RAW264.7 cells. Accompanying with the intracellular catabolic breakdown and exocytosis of Mn-IONPs, RAW264.7 cells also secreted and re-uptook manganese and iron ions to maintain intracellular homeostasis in the succeeding passages. And the metabolic conversion of Mn-IONPs in RAW264.7 cells can affect the expression of ZIP14, DMT1, FPN, SLC30A10, IRP2, FtH, Hamp2 and SPCA1 genes.

Delivery of apigenin-loaded magnetic Fe2O3/Fe3O4@mSiO2 nanocomposites to A549 cells and their antitumor mechanism

This study introduces a mesoporous magnetic nano-system for the delivery of apigenin (API). A targeted therapeutic drug delivery system was prepared based on Fe₂O₃/Fe₃O₄@mSiO₂-HA nanocomposites. Magnetic Fe₂O₃/Fe₃O₄ heterogeneous nanoparticles were first prepared via the rapid-combustion process. The effects of solvent type, solvent volume, calcination temperature, and calcination time on the crystal size and magnetism of the Fe₂O₃/Fe₃O₄ heterogeneous nanoparticles were investigated. The mesoporous silica shell was deposited on the Fe₂O₃/Fe₃O₄ heterogeneous nanoparticles using an improved Stöber method. HA was exploited as the targeting ligand. The specific surface area of the Fe₂O₃/Fe₃O₄@mSiO₂ nanocomposites was 369.6 m²/g, which is 19 times higher than that of the magnetic Fe₂O₃/Fe₃O₄ heterogeneous nanoparticle cores. Drug release properties from the Fe₂O₃/Fe₃O₄@mSiO₂-HA nanocomposites were studied, and the result showed that API-loaded nano-system had sustained release effect. Prussian blue staining and electrochemical performance variation showed that an external magnetic field facilitated cell uptake of Fe₂O₃/Fe₃O₄@mSiO₂-HA nanocomposites. MTT assays showed that the cell inhibition effect of API-Fe₂O₃/Fe₃O₄@mSiO₂-HA was stronger than that of free API at the same drug dose under a magnetic field and Fe₂O₃/Fe₃O₄@mSiO₂-HA nanocomposites showed good biocompatibility. Fluorescence imaging, flow cytometry, western blot, reactive oxygen species (ROS), Superoxide dismutase (SOD) and malondialdehyde (MDA) kits verified that the enhanced therapeutic action was due to the promotion of apoptosis, lipid peroxidation, and ferroptosis. The magnetic nano-system (Fe₂O₃/Fe₃O₄@mSiO₂-HA) showed good magnetic targeting and active hyaluronic acid targeting, and has the potential to provide a targeted delivery platform for many antitumor drugs.

Relaxivity of manganese ferrite nanoparticles

Manganese ferrite nanoparticles are superparamagnetic and have very high saturation magnetization, which makes them candidates for application as MRI contrast agents. Because these nanoparticles are very effective enhancers of transverse relaxation, they are particularly suitable as negative (T₂-weighted) contrast agents. The magnitude of the relaxivity of nanoparticulate Mn ferrites seems to be determined mainly by the method of preparation, their dimensions, and their saturation magnetization.

Biodegradable nanocarriers based on chitosan-modified mesoporous silica nanoparticles for delivery of methotrexate for application in breast cancer treatment

Nanocarriers have demonstrated great promise in the delivery of hydrophobic drugs particularly to tumor spaces by enhanced permeability and retention (EPR) effects. Mesoporous silica nanoparticles (MSNs) are the attractive nanocarrier system to reduce the drug's toxic side effects, enable controlled drug release, prevent drug degradation and provide a biocompatible and biodegradable high surface area carrier. Surface-modified MSNs have been applied to increase drug loading and efficiency. In this study, functionalized MSNs loaded with methotrexate (MTX) were designed for use as a cytotoxic agent. The MSNs were first modified with 3-triethoxysilylpropylamine (APTES) and then with chitosan through covalent coupling mediated by glutaraldehyde. The physicochemical properties of the nanoparticles were optimized for each step. The loading percentage (12.2%) and release profile of MTX as an anti-breast cancer drug, loaded at amine-modified MSNs, were measured via high performance liquid chromatography (HPLC). Moreover, the uptake profiles of fluorescein isothiocyanate (FITC)-labeled MSN-APTES-chitosan with or without MTX were monitored on MCF7 cancer cells via confocal microscopy. Following exposure of nanoparticles to body fluids, they were surrounded by specific proteins that may affect their cellular uptake. Hence, the adsorption profiles of protein corona on the surface of MSN, amine-modified MSN and MTX-loaded MSN-APTES-chitosan were analyzed. The cytotoxic potential for killing breast cancer cells was also studied. The MTX loaded MSN-APTES-chitosan showed a positive effect at a low dose (0.5 μM MTX). In this study, we introduce a new method to synthesize biodegradable MSNs with small and uniform particle size, achieve high MTX loading via covalent amine and chitosan-functionalization, monitor the cellular uptake and demonstrate the potential to decrease the viability of breast cancer cells at low dose.

Immunologically modified MnFe2O4 nanoparticles to synergize photothermal therapy and immunotherapy for cancer treatment

Immunotherapy has been a promising candidate for cancer treatment. The combination of photothermal therapy (PTT) and immunotherapy have shown to cause tumor ablation and induce host immune response. However, this strategy is often hampered by a limited immune response and undesirable immunosuppression. In this work, we developed an immunologically modified nanoplatform, using ovalbumin (OVA)-coated PEGylated MnFe₂O₄ nanoparticles (NPs) loaded with R837 immunoadjuvant (R837-OVA-PEG-MnFe₂O₄ NPs) to synergize PTT and immunotherapy for the treatment of breast cancer. The designed R837-OVA-PEG-MnFe₂O₄ NPs are able to elicit significant immune responses in vitro and in vivo. MnFe₂O₄ NPs also allowed for a reduction of systemic immunosuppression through downregulation of M2-associated cytokines. More importantly, the R837-OVA-PEG-MnFe₂O₄ NPs under laser irradiation effectively inhibited tumor growth and prevented lung metastases, leading to a prolonged survival time and improved survival rate. In addition, the designed multitasking MnFe₂O₄ NPs showed as a good contrast agent for magnetic resonance (MR) imaging to detect orthotopic breast tumor in vivo. Our work provides a novel strategy for combined PTT and improved immunotherapy in the treatment of breast and other metastatic cancers.

Mesoporous Silica Nanoparticles in Bioimaging

A biomedical contrast agent serves to enhance the visualisation of a specific (potentially targeted) physiological region. In recent years, mesoporous silica nanoparticles (MSNs) have developed as a flexible imaging platform of tuneable size/morphology, abundant surface chemistry, biocompatibility and otherwise useful physiochemical properties. This review discusses MSN structural types and synthetic strategies, as well as methods for surface functionalisation. Recent applications in biomedical imaging are then discussed, with a specific emphasis on magnetic resonance and optical modes together with utility in multimodal imaging.

Utility of Silane-Modified Magnesium-Based Magnetic Nanoparticles for Efficient Immobilization of Bacillus thermoamylovorans Lipase

Enzymes and protein's immobilization on magnetic nano supports is emerging as a promising candidate in the food, medical field, and areas of environmental studies. This work presents a study on purified Bacillus thermoamylovorans lipase (BTL) by utilizing tetraethoxysilane (TEOS)-modified magnesium nano ferrite (MgNF) of 20 nm size. Its structural and morphological studies were investigated by powder X-ray diffractometry, high-resolution transmission electron microscopy, etc. Binding of BTL with MgNF was supported by using Fourier transform infrared spectroscopy. Magnetic behavior was examined by the vibrational sample magnetometer and Mössbauer spectrometer graphs. The enzymatic activity of BTL before and after immobilization was studied at different temperatures and reaction time. As per the Lineweaver-Burk plot, immobilized lipase has more biological affinity for fatty acids in comparison to the free lipase, and K_max values of immobilized and free BTL were computed as 6.6 and 7.5 mM respectively, with excellent reusability(> 50%) even till 13 consecutive assay runs. Graphical Abstract.

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Research on iron oxide-based magnetic nanoparticles and their clinical use has been, so far, mainly focused on the spherical shape. However, efforts have been made to develop synthetic routes that produce different anisotropic shapes not only in magnetite nanoparticles, but also in other ferrites, as their magnetic behavior and biological activity can be improved by controlling the shape. Ferrite nanoparticles show several properties that arise from finite-size and surface effects, like high magnetization and superparamagnetism, which make them interesting for use in nanomedicine. Herein, we show recent developments on the synthesis of anisotropic ferrite nanoparticles and the importance of shape-dependent properties for biomedical applications, such as magnetic drug delivery, magnetic hyperthermia and magnetic resonance imaging. A brief discussion on toxicity of iron oxide nanoparticles is also included.

Synthesis, Principles, and Properties of Magnetite Nanoparticles for In Vivo Imaging Applications-A Review

The current nanotechnology era is marked by the emergence of various magnetic inorganic nanometer-sized colloidal particles. These have been extensively applied and hold an immense potential in biomedical applications including, for example, cancer therapy, drug nanocarriers (NCs), or in targeted delivery systems and diagnosis involving two guided-nanoparticles (NPs) as nanoprobes and contrast agents. Considerable efforts have been devoted to designing iron oxide NPs (IONPs) due to their superparamagnetic (SPM) behavior (SPM IONPs or SPIONs) and their large surface-to-volume area allowing more biocompatibility, stealth, and easy bonding to natural biomolecules thanks to grafted ligands, selective-site moieties, and/or organic and inorganic corona shells. Such nanomagnets with adjustable architecture have been the topic of significant progresses since modular designs enable SPIONs to carry out several functions simultaneously such as local drug delivery with real-time monitoring and imaging of the targeted area. Syntheses of SPIONs and adjustments of their physical and chemical properties have been achieved and paved novel routes for a safe use of those tailored magnetic ferrous nanomaterials. Herein we will emphasis a basic notion about NPs magnetism in order to have a better understanding of SPION assets for biomedical applications, then we mainly focus on magnetite iron oxide owing to its outstanding magnetic properties. The general methods of preparation and typical characteristics of magnetite are reviewed, as well as the major biomedical applications of magnetite.