Principles of Magnetic Hyperthermia: A Focus on Using Multifunctional Hybrid Magnetic Nanoparticles

Iron oxide nanoparticles coated with bioactive materials: a viable theragnostic strategy to improve osteosarcoma treatment

Osteosarcoma (OS) is distinguished as a high-grade malignant tumor, characterized by rapid systemic metastasis, particularly to the lungs, resulting in very low survival rates. Understanding the complexities of tumor development and mutation is the need of the hour for the advancement of targeted therapies in cancer care. A significant innovation in this area is the use of nanotechnology, specifically nanoparticles, to tackle various challenges in cancer treatment. Iron oxide nanoparticles stand out in both therapeutic and diagnostic applications, offering a versatile platform for targeted drug delivery, hyperthermia, magneto-thermal therapy, and combinational therapy using modulation of ferroptosis pathways. These nanoparticles are easy to synthesize, non-toxic, biocompatible, and display enhanced circulation time within the system. They can also be easily conjugated to anti-cancer drugs, targeting agents, or genetic vectors that respond to specific stimuli or pH changes. The surface functionalization of these nanoparticles using bioactive molecules unveils a promising and effective nanoparticle system for assisting osteosarcoma therapy. This review will summarize the current conventional therapies for osteosarcoma and their disadvantages, the synthesis and modification of iron oxide nanoparticles documented in the literature, cellular targeting and uptake mechanism, with focus on their functionalization using natural biomaterials and application strategies towards management of osteosarcoma. The review also compiles the translational challenges and future prospects that must be addressed for clinical advancements of iron oxide based osteosarcoma treatment in the future.

Characteristics and Antitumor Activity of Doxorubicin-Loaded Multifunctional Iron Oxide Nanoparticles in MEC1 and RM1 Cell Lines

The rapid progress in nanotechnology has introduced multifunctional iron oxide nanoparticles as promising agents in cancer treatment. This research focused on the synthesis and assessment of citric-acid-coated, folic-acid-conjugated nanoparticles loaded with doxorubicin, evaluating their therapeutic potential in tumor models. An advanced automated continuous technology line (CTL) utilizing a controlled co-precipitation method was employed to produce highly dispersive, multifunctional nanofluids with a narrow size distribution. Various techniques, including dynamic light scattering (DLS), electrophoretic light scattering (ELS), X-ray diffraction (XRD), and transmission electron microscopy (TEM), were employed to examine the particle size, zeta potential, structure, and morphology. Magnetic properties were analyzed through vibrating sample magnetometry (VSM), and surface modifications were confirmed via UV-visible (UV-Vis) and Fourier-Transform Infrared (FTIR) spectroscopy. Cytotoxicity and drug delivery efficiency were evaluated in vitro using RM1 (prostate cancer) and MEC1 (chronic lymphocytic leukemia) cell lines. Fluorescence microscopy demonstrated the successful intracellular delivery of doxorubicin, showcasing the nanoparticles' potential for targeted cancer therapy. However, folic-acid-conjugated nanoparticles exhibited diminished effectiveness over time. This study highlights the importance of nanoparticle optimization for enhancing therapeutic performance. Further research should aim to improve nanoparticle formulations and explore their long-term impacts for the development of safe, targeted cancer treatments.

Breast cancer epidemiology, diagnostic barriers, and contemporary trends in breast nanotheranostics and mechanisms of targeting

INTRODUCTION

Breast cancer is one of the main causes of mortality in women globally. Early and accurate diagnosis represents a milestone in cancer management. Several breast cancer diagnostic agents are available. Many chemotherapeutic agents in conventional dosage forms are approved; nevertheless, they lack cancer cell specificity, resulting in improper treatment and undesirable side effects. Recently, nanotheranostics has emerged as a new paradigm to achieve safe and effective cancer diagnosis and management.

AREA COVERED

This review provides insight into breast cancer epidemiology, barriers hindering the early diagnosis, and effective delivery of chemotherapeutics. Also, conventional diagnostic agents and recent nanotheranostic platforms have been used in breast cancer. In addition, mechanisms of cancer cell targeting and nano-carrier surface functionalization as an effective approach for chemotherapeutic targeting were reviewed along with future perspectives.

EXPERT OPINION

We proposed that modified nano-carriers may provide an efficacious approach for breast cancer drug targeting. These nanotheranostics need more clinical evaluations to confirm their efficacy in cancer management. In addition, we recommend the use of artificial intelligence (AI) as a promising approach for early and efficient assessment of breast lesions. AI allows better interpretation and analysis of nanotheranostic data, which minimizes misdiagnosis and avoids the belated intervention of health care providers.

Comprehensive Analysis of the Potential Toxicity of Magnetic Iron Oxide Nanoparticles for Medical Applications: Cellular Mechanisms and Systemic Effects

Owing to recent advancements in nanotechnology, magnetic iron oxide nanoparticles (MNPs), particularly magnetite (Fe3O4) and maghemite (γ-Fe2O3), are currently widely employed in the field of medicine. These MNPs, characterized by their large specific surface area, potential for diverse functionalization, and magnetic properties, have found application in various medical domains, including tumor imaging (MRI), radiolabelling, internal radiotherapy, hyperthermia, gene therapy, drug delivery, and theranostics. However, ensuring the non-toxicity of MNPs when employed in medical practices is paramount. Thus, ongoing research endeavors are essential to comprehensively understand and address potential toxicological implications associated with their usage. This review aims to present the latest research and findings on assessing the potential toxicity of magnetic nanoparticles. It meticulously delineates the primary mechanisms of MNP toxicity at the cellular level, encompassing oxidative stress, genotoxic effects, disruption of the cytoskeleton, cell membrane perturbation, alterations in the cell cycle, dysregulation of gene expression, inflammatory response, disturbance in ion homeostasis, and interference with cell migration and mobility. Furthermore, the review expounds upon the potential impact of MNPs on various organs and systems, including the brain and nervous system, heart and circulatory system, liver, spleen, lymph nodes, skin, urinary, and reproductive systems.

Advanced Nanomaterials for Cancer Therapy: Gold, Silver, and Iron Oxide Nanoparticles in Oncological Applications

Cancer remains one of the most challenging health issues globally, demanding innovative therapeutic approaches for effective treatment. Nanoparticles, particularly those composed of gold, silver, and iron oxide, have emerged as promising candidates for changing cancer therapy. This comprehensive review demonstrates the landscape of nanoparticle‐based oncological interventions, focusing on the remarkable advancements and therapeutic potentials of gold, silver, and iron oxide nanoparticles. Gold nanoparticles have garnered significant attention for their exceptional biocompatibility, tunable surface chemistry, and distinctive optical properties, rendering them ideal candidates for various cancer diagnostic and therapeutic strategies. Silver nanoparticles, renowned for their antimicrobial properties, exhibit remarkable potential in cancer therapy through multiple mechanisms, including apoptosis induction, angiogenesis inhibition, and drug delivery enhancement. With their magnetic properties and biocompatibility, iron oxide nanoparticles offer unique cancer diagnosis and targeted therapy opportunities. This review critically examines the recent advancements in the synthesis, functionalization, and biomedical applications of these nanoparticles in cancer therapy. Moreover, the challenges are discussed, including toxicity concerns, immunogenicity, and translational barriers, and ongoing efforts to overcome these hurdles are highlighted. Finally, insights into the future directions of nanoparticle‐based cancer therapy and regulatory considerations, are provided aiming to accelerate the translation of these promising technologies from bench to bedside.

Effect of Polymer and Cell Membrane Coatings on Theranostic Applications of Nanoparticles: A Review

The recent decade has witnessed a remarkable surge in the field of nanoparticles, from their synthesis, characterization, and functionalization to diverse applications. At the nanoscale, these particles exhibit distinct physicochemical properties compared to their bulk counterparts, enabling a multitude of applications spanning energy, catalysis, environmental remediation, biomedicine, and beyond. This review focuses on specific nanoparticle categories, including magnetic, gold, silver, and quantum dots (QDs), as well as hybrid variants, specifically tailored for biomedical applications. A comprehensive review and comparison of prevalent chemical, physical, and biological synthesis methods are presented. To enhance biocompatibility and colloidal stability, and facilitate surface modification and cargo/agent loading, nanoparticle surfaces are coated with different synthetic polymers and very recently, cell membrane coatings. The utilization of polymer- or cell membrane-coated nanoparticles opens a wide variety of biomedical applications such as magnetic resonance imaging (MRI), hyperthermia, photothermia, sample enrichment, bioassays, drug delivery, etc. With this review, the goal is to provide a comprehensive toolbox of insights into polymer or cell membrane-coated nanoparticles and their biomedical applications, while also addressing the challenges involved in translating such nanoparticles from laboratory benchtops to in vitro and in vivo applications. Furthermore, perspectives on future trends and developments in this rapidly evolving domain are provided.

Research on Spatial Localization Method of Magnetic Nanoparticle Samples Based on Second Harmonic Waves

Existing magnetic tracer detection systems primarily rely on fundamental wave signal acquisition using non-differential sensor configurations. These sensors are highly susceptible to external interference and lack tomographic localization capabilities, hindering their clinical application. To address these limitations, this paper presents a novel method for achieving the deep spatial localization of tracers. The method exploits second harmonic signal detection at non-zero field points. By considering the combined nonlinear characteristics of the coil's axial spatial magnetic field distribution and the Langevin function, a correlation model linking the signal peak and bias field is established. This model enables the determination of the tracer's precise spatial location. Building on this framework, a handheld device for localizing magnetic nanoparticle tracers was developed. The device harnesses the second harmonic response generated by coupling an AC excitation field with a DC bias field. Our findings demonstrate that under conditions of reduced coil turns and weak excitation fields, the DC bias field exhibits exclusive dependence on the axial distance of the detection point, independent of particle concentration. This implies that the saturated DC bias field corresponding to the second harmonic signal can be used to determine the magnetic nanoparticle sample detection depth. The experimental results validated the method's high accuracy, with axial detection distance and concentration reduction errors of only 4.8% and 4.1%, respectively. This research paves the way for handheld probes capable of tomographic tracer detection, offering a novel approach for advancing magnetically sensitive biomedical detection technologies.

In Silico Approach to Model Heat Distribution of Magnetic Hyperthermia in the Tumoral and Healthy Vascular Network Using Tumor-on-a-Chip to Evaluate Effective Therapy

Glioblastoma multiforme (GBM) is the most severe form of brain cancer in adults, characterized by its complex vascular network that contributes to resistance to conventional therapies. Thermal therapies, such as magnetic hyperthermia (MHT), emerge as promising alternatives, using heat to selectively target tumor cells while minimizing damage to healthy tissues. The organ-on-a-chip can replicate this complex vascular network of GBM, allowing for detailed investigations of heat dissipation in MHT, while computational simulations refine treatment parameters. In this in silico study, tumor-on-a-chip models were used to optimize MHT therapy by comparing heat dissipation in normal and abnormal vascular networks, considering geometries, flow rates, and concentrations of magnetic nanoparticles (MNPs). In the high vascular complexity model, the maximum velocity was 19 times lower than in the normal vasculature model and 4 times lower than in the low-complexity tumor model, highlighting the influence of vascular complexity on velocity and temperature distribution. The MHT simulation showed greater heat intensity in the central region, with a flow rate of 1 µL/min and 0.5 mg/mL of MNPs being the best conditions to achieve the therapeutic temperature. The complex vasculature model had the lowest heat dissipation, reaching 44.15 °C, compared to 42.01 °C in the low-complexity model and 37.80 °C in the normal model. These results show that greater vascular complexity improves heat retention, making it essential to consider this heterogeneity to optimize MHT treatment. Therefore, for an efficient MHT process, it is necessary to simulate ideal blood flow and MNP conditions to ensure heat retention at the tumor site, considering its irregular vascularization and heat dissipation for effective destruction.

Functionalized Magnetic Fe3O4 Nanoparticles for Targeted Methotrexate Delivery in Ovarian Cancer Therapy

Magnetic Fe3O4 nanoparticles (MNPs) functionalized with (3-aminopropylo)trietoksysilan (APTES) or N-carboxymethylchitosan (CMC) were proposed as nanocarriers of methotrexate (MTX) to target ovarian cancer cell lines. The successful functionalization of the obtained nanostructures was confirmed by FT-IR spectroscopy. The nanoparticles were characterized by transmission electron spectroscopy (TEM) and dynamic light scattering (DLS) techniques. Their potential zeta, magnetization, and hyperthermic properties were also explored. MTX was conjugated with the nanocarriers by ionic bonds or by amide bonds. The drug release kinetics were examined at different pH and temperatures. The MTT assay showed no toxicity of the MNPs[APTES] and MNPs[CMC]. Finally, the cytotoxicity of the nanostructures with MTX attached towards the ovarian cancer cells was measured. The sensitivity and resistance to methotrexate was determined in simplistic 2D and spheroid 3D conditions. The cytotoxicity tests of the tested nanostructures showed similar values for inhibiting the proliferation of ovarian cancer cells as methotrexate in its free form. Conjugating MTX with nanoparticles allows the drug to be directed to the target site using an external magnetic field, reducing overall toxicity. Combining this approach with hyperthermia could enhance the therapeutic effect in vivo compared to free MTX, though further research on advanced 3D models is needed.

Phototactic/Photosynthetic/Magnetic-Powered Chlamydomonas Reinhardtii-Metal-Organic Frameworks Micro/Nanomotors for Intelligent Thrombolytic Management and Ischemia Alleviation

Thrombosis presents a critical health threat globally, with high mortality and incidence rates. Clinical treatment faces challenges such as low thrombolytic agent bioavailability, thrombosis recurrence, ischemic hypoxia damage, and neural degeneration. This study developed biocompatible Chlamydomonas Reinhardtii micromotors (CHL) with photo/magnetic capabilities to address these needs. These CHL micromotors, equipped with phototaxis and photosynthesis abilities, offer promising solutions. A core aspect of this innovation involves incorporating polysaccharides (glycol chitosan (GCS) and fucoidan (F)) into ferric Metal-organic frameworks (MOFs), loaded with urokinase (UK), and subsequently self-assembled onto the multimodal CHL, forming a core-shell microstructure (CHL@GCS/F-UK-MOF). Under light-navigation, CHL@GCS/F-UK-MOF is shown to penetrate thrombi, enhancing thrombolytic biodistribution. Combining CHL@GCS/F-UK-MOF with the magnetic hyperthermia technique achieves stimuli-responsive multiple-release, accelerating thrombolysis and rapidly restoring blocked blood vessels. Moreover, this approach attenuates thrombi-induced ischemic hypoxia disorder and tissue damage. The photosynthetic and magnetotherapeutic properties of CHL@GCS/F-UK-MOF, along with their protective effects, including reduced apoptosis, enhanced behavioral function, induced Heat Shock Protein (HSP), polarized M2 macrophages, and mitigated hypoxia, are confirmed through biochemical, microscopic, and behavioral assessments. This multifunctional biomimetic platform, integrating photo-magnetic techniques, offers a comprehensive approach to cardiovascular management, advancing related technologies.

The Recent Applications of Magnetic Nanoparticles in Biomedical Fields

Magnetic nanoparticles (MNPs) have found extensive application in the biomedical domain due to their enhanced biocompatibility, minimal toxicity, and strong magnetic responsiveness. MNPs exhibit great potential as nanomaterials in various biomedical applications, including disease detection and cancer therapy. Typically, MNPs consist of a magnetic core surrounded by surface modification coatings, such as inorganic materials, organic molecules, and polymers, forming a nucleoshell structure that mitigates nanoparticle agglomeration and enhances targeting capabilities. Consequently, MNPs exhibit magnetic responsiveness in vivo for transportation and therapeutic effects, such as enhancing medical imaging resolution and localized heating at the site of injury. MNPs are utilized for specimen purification through targeted binding and magnetic separation in vitro, thereby optimizing efficiency and expediting the process. This review delves into the distinctive functional characteristics of MNPs as well as the diverse bioactive molecules employed in their surface coatings and their corresponding functionalities. Additionally, the advancement of MNPs in various applications is outlined. Additionally, we discuss the advancements of magnetic nanoparticles in medical imaging, disease treatment, and in vitro assays, and we anticipate the future development prospects and obstacles in this field. The objective is to furnish readers with a thorough comprehension of the recent practical utilization of MNPs in biomedical disciplines.

Biocatalyst immobilization on magnetic nano-architectures for potential applications in condensation reactions

In this review article, a perspective on the immobilization of various hydrolytic enzymes onto magnetic nanoparticles for synthetic organic chemistry applications is presented. After a first part giving short overview on nanomagnetism and highlighting advantages and disadvantages of immobilizing enzymes on magnetic nanoparticles (MNPs), the most important hydrolytic enzymes and their applications were summarized. A section reviewing the immobilization techniques with a particular focus on supporting enzymes on MNPs introduces the reader to the final chapter describing synthetic organic chemistry applications of small molecules (flavour esters) and polymers (polyesters and polyamides). Finally, the conclusion and perspective section gives the author's personal view on further research discussing the new idea of a synergistic rational design of the magnetic and biocatalytic component to produce novel magnetic nano-architectures.

Evaluation of Advanced Nanomaterials for Cancer Diagnosis and Treatment

Cancer is a persistent global disease and a threat to the human species, with numerous cases reported every year. Over recent decades, a steady but slowly increasing mortality rate has been observed. While many attempts have been made using conventional methods alone as a theragnostic strategy, they have yielded very little success. Most of the shortcomings of such conventional methods can be attributed to the high demands of industrial growth and ever-increasing environmental pollution. This requires some high-tech biomedical interventions and other solutions. Thus, researchers have been compelled to explore alternative methods. This has brought much attention to nanotechnology applications, specifically magnetic nanomaterials, as the sole or conjugated theragnostic methods. The exponential growth of nanomaterials with overlapping applications in various fields is due to their potential properties, which depend on the type of synthesis route used. Either top-down or bottom-up strategies synthesize various types of NPs. The top-down only branches out to one method, i.e., physical, and the bottom-up has two methods, chemical and biological syntheses. This review highlights some synthesis techniques, the types of nanoparticle properties each technique produces, and their potential use in the biomedical field, more specifically for cancer. Despite the evident drawbacks, the success achieved in furthering nanoparticle applications to more complex cancer stages and locations is unmatched.

Comparative studies on the cytotoxic effects induced by iron oxide nanoparticles in cancerous and noncancerous human lung cells subjected to an alternating magnetic field

The cytotoxic effects of water-based ferrofluids composed of iron oxide nanoparticles, including magnetite (Fe3O4) and maghemite (γ-Fe2O3), ranging from 15 to 100 nm, were examined on various lung cancer cells including adenocarcinomic human alveolar basal epithelial cells (A549), nonsmall lung squamous cell carcinoma (H1703), small cell lung cancer cells (DMS 114), and normal bronchial epithelial cells (BEAS-2B). The cytotoxic effect was evaluated both with and without exposure to an alternating magnetic field (AMF). The studies revealed that neither AMF nor iron oxide nanoparticles when tested individually, produced cytotoxic effects on either cancerous or noncancerous cells. However, when applied together, they led to a significant decrease in cell viability and proliferative capacity due to the enhanced effects of magnetic fluid hyperthermia (MFH). The most pronounced effects were found for maghemite (<50 nm) when subjected to an AMF. Notably, A549 cells exhibited the highest resistance to the proposed hyperthermia treatment. BEAS-2B cells demonstrated susceptibility to magnetized iron oxide nanoparticles, similar to the response observed in lung cancer cells. The studies provide evidence that MFH is a promising strategy as a standalone treatment for different types of lung cancer cells. Nevertheless, to prevent any MFH-triggered adverse effects on normal lung cells, targeted magnetic ferrofluids should be designed.

Magnetic hybrid Pd/Fe-oxide nanoparticles meet the demands for ablative thermo-brachytherapy

OBJECTIVE

To investigate the potential of hybrid Pd/Fe-oxide magnetic nanoparticles designed for thermo-brachytherapy of breast cancer, considering their specific loss power (SLP) and clinical constraints in the applied magnetic field.

METHODS

Hybrid nanoparticles consisting of palladium-core and iron oxide shell of increasing thickness, were suspended in water and their SLPs were measured at varying magnetic fields (12-26 mT peak) and frequencies (50-730 kHz) with a commercial alternating magnetic field generator (magneTherm™ Digital, nanoTherics Ltd.).

RESULTS

Validation of the heating device used in this study with commercial HyperMag-C nanoparticles showed a small deviation (±4%) over a period of 1 year, confirming the reliability of the method. The integration of dual thermometers, one in the center and one at the bottom of the sample vial, allowed monitoring of homogeneity of the sample suspensions. SLPs measurements on a series of nanoparticles of increasing sizes showed the highest heating for the diameter of 21 nm (SLP = 225 W/g) at the applied frequencies of 346 and 730 kHz. No heating was observed for the nanoparticles with the size <14 nm, confirming the importance of the size-parameter. The heating ability of the best performing Pd/Fe-oxide-21 was calculated to be sufficient to ablate tumors with a radius ±4 and 12 mm using 10 and 1 mg/mL nanoparticle concentration, respectively.

CONCLUSIONS

Nanoparticles consisting of non-magnetic palladium-core and magnetic iron oxide shell are suitable for magnetic hyperthermia/thermal ablation under clinically safe conditions of 346 kHz and 19.1 mT, with minimal eddy current effects in combination with maximum SLP.

Electrospun Nanofibers: Shaping the Future of Controlled and Responsive Drug Delivery

Electrospun nanofibers for drug delivery systems (DDS) introduce a revolutionary means of administering pharmaceuticals, holding promise for both improved drug efficacy and reduced side effects. These biopolymer nanofiber membranes, distinguished by their high surface area-to-volume ratio, biocompatibility, and biodegradability, are ideally suited for pharmaceutical and biomedical applications. One of their standout attributes is the capability to offer the controlled release of the active pharmaceutical ingredient (API), allowing custom-tailored release profiles to address specific diseases and administration routes. Moreover, stimuli-responsive electrospun DDS can adapt to conditions at the drug target, enhancing the precision and selectivity of drug delivery. Such localized API delivery paves the way for superior therapeutic efficiency while diminishing the risk of side effects and systemic toxicity. Electrospun nanofibers can foster better patient compliance and enhanced clinical outcomes by amplifying the therapeutic efficiency of routinely prescribed medications. This review delves into the design principles and techniques central to achieving controlled API release using electrospun membranes. The advanced drug release mechanisms of electrospun DDS highlighted in this review illustrate their versatility and potential to improve the efficacy of medical treatments.

Advancement in magnetic hyperthermia-based targeted therapy for cancer treatment

Magnetic hyperthermia utilizing magnetic nanoparticles (MNPs) and an alternating magnetic field (AMF) represents a promising approach in the field of cancer treatment. Active targeting has emerged as a valuable strategy to enhance the effectiveness and specificity of drug delivery. Active targeting utilizes specific biomarkers that are predominantly found in abundance on cancer cells while being minimally expressed on healthy cells. Current comprehensive review provides an overview of several cancer-specific biomarkers, including human epidermal growth factor, transferrin, folate, luteinizing hormone-releasing hormone, integrin, cluster of differentiation (CD) receptors such as CD90, CD95, CD133, CD20, and CD44 also CXCR4 and vascular endothelial growth factor, these biomarkers bind to ligands present on the surface of MNPs, enabling precise targeting. Additionally, this review touches various combination therapies employed to combat cancer. Magnetic hyperthermia synergistically enhances the efficacy of conventional cancer treatments such as targeted chemotherapy, radiation therapy, gene therapy, and immunotherapy.

Optimization of cobalt ferrite magnetic nanoparticle as a theranostic agent: MRI and hyperthermia

OBJECTIVE

Magnetic nanoparticles (MNPs) are considered a theranostic agent in MR imaging, playing an effective role in inducing magnetic hyperthermia. Since, high-performance magnetic theranostic agents are characterized by superparamagnetic behavior and high anisotropy, in this study, cobalt ferrite MNPs were optimized and investigated as a theranostic agent.

METHODS

CoFe2O4@Au@dextran particles were synthesized and characterized by DLS, HRTEM, SEM, XRD, FTIR, and VSM methods. After cytotoxicity evaluation, MR imaging parameters (r1, r2 and r2 / r1) were calculated for these nanostructures. Afterward, magnetic hyperthermia at the frequency of 425 kHz was applied to calculate specific loss power (SLP).

RESULTS

Formation of CoFe2O4@Au@dextran was confirmed by UV-Visible spectrophotometry. On the basis of the relaxometric and hyperthermia induction findings of nanostructures in all stages of synthesis, the CoFe2O4@Au@dextran could produce the highest parameters of r2 and r2/r1 and SLP with values ​​of 389.7, 51.2 mM-1 s-1, and 2449 W/g, respectively.

CONCLUSION

The formation of multi-core MNPs by dextran coating is expected to improve the magnetic properties of the nanostructure, leading to optimization of theranostic parameters, so that CoFe2O4@Au@dextran NPs can create contrast-enhanced images more than three times the clinical use and require less contrast agent, reducing side effects. Accordingly, CoFe2O4@Au@dextran can be introduced as a suitable theranostic nanostructure with optimal efficiency.

Recent advances of magnetic chitosan hydrogel: Preparation, properties and applications

Magnetic chitosan hydrogels are organic-inorganic composite material with the characteristics of both magnetic materials and natural polysaccharides. Due to its biocompatibility, low toxicity and biodegradability, chitosan, a natural polymer has been widely used for preparing magnetic hydrogels. The addition of magnetic nanoparticles to chitosan hydrogels not only improves their mechanical strength, but also endows them with magnetic thermal effects, targeting capabilities, magnetically-sensitive release characteristics, easy separation and recovery, thus enabling them to be used in various applications including drug delivery, magnetic resonance imaging, magnetothermal therapy, and adsorption of heavy metals and dyes. In this review, the physical and chemical crosslinking methods of chitosan hydrogels and the methods for binding magnetic nanoparticles in hydrogel networks are first introduced. Subsequently, the properties of magnetic chitosan hydrogels were summarized including mechanical properties, self-healing, pH responsiveness and properties in magnetic fields. Finally, the potential for further technological and applicative advancements of magnetic chitosan hydrogels is discussed.

In vivo Biodistribution and Clearance of Magnetic Iron Oxide Nanoparticles for Medical Applications

Magnetic iron oxide nanoparticles (magnetite and maghemite) are intensively studied due to their broad potential applications in medical and biological sciences. Their unique properties, such as nanometric size, large specific surface area, and superparamagnetism, allow them to be used in targeted drug delivery and internal radiotherapy by targeting an external magnetic field. In addition, they are successfully used in magnetic resonance imaging (MRI), hyperthermia, and radiolabelling. The appropriate design of nanoparticles allows them to be delivered to the desired tissues and organs. The desired biodistribution of nanoparticles, eg, cancerous tumors, is increased using an external magnetic field. Thus, knowledge of the biodistribution of these nanoparticles is essential for medical applications. It allows for determining whether nanoparticles are captured by the desired organs or accumulated in other tissues, which may lead to potential toxicity. This review article presents the main organs where nanoparticles accumulate. The sites of their first uptake are usually the liver, spleen, and lymph nodes, but with the appropriate design of nanoparticles, they can also be accumulated in organs such as the lungs, heart, or brain. In addition, the review describes the factors affecting the biodistribution of nanoparticles, including their size, shape, surface charge, coating molecules, and route of administration. Modern techniques for determining nanoparticle accumulation sites and concentration in isolated tissues or the body in vivo are also presented.

How Magnetic Composites are Effective Anticancer Therapeutics? A Comprehensive Review of the Literature

Chemotherapy is the most prominent route in cancer therapy for prolonging the lifespan of cancer patients. However, its non-target specificity and the resulting off-target cytotoxicities have been reported. Recent in vitro and in vivo studies using magnetic nanocomposites (MNCs) for magnetothermal chemotherapy may potentially improve the therapeutic outcome by increasing the target selectivity. In this review, magnetic hyperthermia therapy and magnetic targeting using drug-loaded MNCs are revisited, focusing on magnetism, the fabrication and structures of magnetic nanoparticles, surface modifications, biocompatible coating, shape, size, and other important physicochemical properties of MNCs, along with the parameters of the hyperthermia therapy and external magnetic field. Due to the limited drug-loading capacity and low biocompatibility, the use of magnetic nanoparticles (MNPs) as drug delivery system has lost traction. In contrast, MNCs show higher biocompatibility, multifunctional physicochemical properties, high drug encapsulation, and multi-stages of controlled release for localized synergistic chemo-thermotherapy. Further, combining various forms of magnetic cores and pH-sensitive coating agents can generate a more robust pH, magneto, and thermo-responsive drug delivery system. Thus, MNCs are ideal candidate as smart and remotely guided drug delivery system due to a) their magneto effects and guide-ability by the external magnetic fields, b) on-demand drug release performance, and c) thermo-chemosensitization under an applied alternating magnetic field where the tumor is selectively incinerated without harming surrounding non-tumor tissues. Given the important effects of synthesis methods, surface modifications, and coating of MNCs on their anticancer properties, we reviewed the most recent studies on magnetic hyperthermia, targeted drug delivery systems in cancer therapy, and magnetothermal chemotherapy to provide insights on the current development of MNC-based anticancer nanocarrier.

Influence of the modifiers in polyol method on magnetically induced hyperthermia and biocompatibility of ultrafine magnetite nanoparticles

Magnetite nanoparticles (Fe₃O₄ NPs) are widely tested in various biomedical applications, including magnetically induced hyperthermia. In this study, the influence of the modifiers, i.e., urotropine, polyethylene glycol, and NH₄HCO_3, on the size, morphology, magnetically induced hyperthermia effect, and biocompatibility were tested for Fe₃O₄ NPs synthesized by polyol method. The nanoparticles were characterized by a spherical shape and similar size of around 10 nm. At the same time, their surface is functionalized by triethylene glycol or polyethylene glycol, depending on the modifiers. The Fe₃O₄ NPs synthesized in the presence of urotropine had the highest colloidal stability related to the high positive value of zeta potential (26.03 ± 0.55 mV) but were characterized by the lowest specific absorption rate (SAR) and intrinsic loss power (ILP). The highest potential in the hyperthermia applications have NPs synthesized using NH₄HCO₃, for which SAR and ILP were equal to 69.6 ± 5.2 W/g and 0.613 ± 0.051 nHm²/kg, respectively. Their application possibility was confirmed for a wide range of magnetic fields and by cytotoxicity tests. The absence of differences in toxicity to dermal fibroblasts between all studied NPs was confirmed. Additionally, no significant changes in the ultrastructure of fibroblast cells were observed apart from the gradual increase in the number of autophagous structures.

Magnetic Nanoclusters Stabilized with Poly[3,4-Dihydroxybenzhydrazide] as Efficient Therapeutic Agents for Cancer Cells Destruction

Magnetic structures exhibiting large magnetic moments are sought after in theranostic approaches that combine magnetic hyperthermia treatment (MH) and diagnostic magnetic resonance imaging in oncology, since they offer an enhanced magnetic response to an external magnetic field. We report on the synthesized production of a core-shell magnetic structure using two types of magnetite nanoclusters (MNC) based on a magnetite core and polymer shell. This was achieved through an in situ solvothermal process, using, for the first time, 3,4-dihydroxybenzhydrazide (DHBH) and poly[3,4-dihydroxybenzhydrazide] (PDHBH) as stabilizers. Transmission electron microscopy (TEM) analysis showed the formation of spherical MNC, X-ray photoelectronic spectroscopy (XPS) and Fourier transformed infrared (FT-IR) analysis proved the existence of the polymer shell. Magnetization measurement showed saturation magnetization values of 50 emu/g for PDHBH@MNC and 60 emu/g for DHBH@MNC with very low coercive field and remanence, indicating that the MNC are in a superparamagnetic state at room temperature and are thus suitable for biomedical applications. MNCs were investigated in vitro, on human normal (dermal fibroblasts-BJ) and tumor (colon adenocarcinoma-CACO2, and melanoma-A375) cell lines, in view of toxicity, antitumor effectiveness and selectivity upon magnetic hyperthermia. MNCs exhibited good biocompatibility and were internalized by all cell lines (TEM), with minimal ultrastructural changes. By means of flowcytometry apoptosis detection, fluorimetry, spectrophotometry for mitochondrial membrane potential, oxidative stress, ELISA-caspases, and Western blot-p53 pathway, we show that MH efficiently induced apoptosis mostly via the membrane pathway and to a lower extent by the mitochondrial pathway, the latter mainly observed in melanoma. Contrarily, the apoptosis rate was above the toxicity limit in fibroblasts. Due to its coating, PDHBH@MNC showed selective antitumor efficacy and can be further used in theranostics since the PDHBH polymer provides multiple reaction sites for the attachment of therapeutic molecules.

Self-Heating Flower-like Nanoconstructs with Limited Incorporation of Yttrium in Maghemite: Effect of Chemical Composition on Heating Efficiency, Cytotoxicity and Genotoxicity

Partial cation substitution can significantly change the physical properties of parent compounds. By controlling the chemical composition and knowing the mutual relationship between composition and physical properties, it is possible to tailor the properties of materials to those that are superior for desired technological application. Using the polyol synthesis procedure, a series of yttrium-substituted iron oxide nanoconstructs, γ-Fe_2-xY_xO₃ (YIONs), was prepared. It was found that Y³⁺ could substitute Fe³⁺ in the crystal structures of maghemite (γ-Fe₂O₃) up to a limited concentration of ~1.5% (γ-Fe_1.969Y_0.031O₃). Analysis of TEM micrographs showed that crystallites or particles were aggregated in flower-like structures with diameters from 53.7 ± 6.2 nm to 97.3 ± 37.0 nm, depending on yttrium concentration. To be investigated for potential applications as magnetic hyperthermia agents, YIONs were tested twice: their heating efficiency was tested and their toxicity was investigated. The Specific Absorption Rate (SAR) values were in the range of 32.6 W/g to 513 W/g and significantly decreased with increased yttrium concentration in the samples. Intrinsic loss power (ILP) for γ-Fe₂O₃ and γ-Fe_1.995Y_0.005O₃ were ~8-9 nH·m²/Kg, which pointed to their excellent heating efficiency. IC₅₀ values of investigated samples against cancer (HeLa) and normal (MRC-5) cells decreased with increased yttrium concentration and were higher than ~300 μg/mL. The samples of γ-Fe_2-xY_xO₃ did not show a genotoxic effect. The results of toxicity studies show that YIONs are suitable for further in vitro/in vivo studies toward to their potential medical applications, while results of heat generation point to their potential use in magnetic hyperthermia cancer treatment or use as self-heating systems for other technological applications such as catalysis.

Proton Therapy, Magnetic Nanoparticles and Hyperthermia as Combined Treatment for Pancreatic BxPC3 Tumor Cells

We present an investigation of the effects on BxPC3 pancreatic cancer cells of proton therapy combined with hyperthermia, assisted by magnetic fluid hyperthermia performed with the use of magnetic nanoparticles. The cells' response to the combined treatment has been evaluated by means of the clonogenic survival assay and the estimation of DNA Double Strand Breaks (DSBs). The Reactive Oxygen Species (ROS) production, the tumor cell invasion and the cell cycle variations have also been studied. The experimental results have shown that the combination of proton therapy, MNPs administration and hyperthermia gives a clonogenic survival that is much smaller than the single irradiation treatment at all doses, thus suggesting a new effective combined therapy for the pancreatic tumor. Importantly, the effect of the therapies used here is synergistic. Moreover, after proton irradiation, the hyperthermia treatment was able to increase the number of DSBs, even though just at 6 h after the treatment. Noticeably, the magnetic nanoparticles' presence induces radiosensitization effects, and hyperthermia increases the production of ROS, which contributes to cytotoxic cellular effects and to a wide variety of lesions including DNA damage. The present study indicates a new way for clinical translation of combined therapies, also in the vision of an increasing number of hospitals that will use the proton therapy technique in the near future for different kinds of radio-resistant cancers.

Role of Dipolar Interactions on the Determination of the Effective Magnetic Anisotropy in Iron Oxide Nanoparticles

Challenging magnetic hyperthermia (MH) applications of immobilized magnetic nanoparticles require detailed knowledge of the effective anisotropy constant (K_eff ) to maximize heat release. Designing optimal MH experiments entails the precise determination of magnetic properties, which are, however, affected by the unavoidable concurrence of magnetic interactions in common experimental conditions. In this work, a mean-field energy barrier model (ΔE), accounting for anisotropy (E_A ) and magnetic dipolar (E_D ) energy, is proposed and used in combination with AC measurements to a specifically developed model system of spherical magnetic nanoparticles with well-controlled silica shells, acting as a spacer between the magnetic cores. This approach makes it possible to experimentally demonstrate the mean field dipolar interaction energy prediction with the interparticle distance, d_ij , E_D ≈ 1/d_ij ³ and obtain the E_A as the asymptotic limit for very large d_ij . In doing so, K_eff uncoupled from interaction contributions is obtained for the model system (iron oxide cores with average sizes of 8.1, 10.2, and 15.3 nm) revealing to be 48, 23, and 11 kJ m^-3 , respectively, close to bulk magnetite/maghemite values and independent from the specific spacing shell thicknesses selected for the study.

An Alternating Magnetic Field-Controlled Drug Delivery System Based on 4,4'-Azobis (4-cyanovaleric Acid)-Functioned Fe3O4@Chitosan Nanoparticles

Herein, we designed chitosan-coated Fe₃O₄ nanocomposites for the control release of drugs by an alternating magnetic field (AMF). The chitosan-coated Fe₃O₄ nanoparticles (Fe₃O₄@CS) were prepared by a alkaline co-precipitation method, and then, the model drug toluidine blue (TB) was covalently grafted onto the surface of the nanocomposite by a two-step amide reaction with the thermosensitive molecule 4,4'-azobis (4-cyanovaleric acid) (ACVA) as the linker group. The prepared nanocomposites were superparamagnetic and showed high magnetization saturation (about 54.0 emu g^-1). In vitro hydrothermal release studies showed that most parts of the TB would be effectively enclosed within the nanocarriers at lower ambient temperatures (23 or 37 °C) due to the molecular bonding of ACVA. The results of kinetic fitting of hydrothermal release data showed that TB released from nanoparticles followed first-order kinetics (R² > 0.99) and the Korsemeyer-Peppas model (R² > 0.99, n < 0.5). Most importantly, a single magnetron release experiment demonstrated an approximately linear relationship between the cumulative release of the drug and the duration of action of AMF (R² = 0.9712). Moreover, the increase in the cumulative release of the drug can be controlled by controlling the switch of the AMF generation device. Therefore, the ACVA-modified Fe₃O₄@CS nanocarrier designed in this study is a promising model for drug delivery that enables the control of drug release dose by AMF.

Effect of Cobalt Ferrite Nanoparticles in a Hydrophilic Shell on the Conductance of Bilayer Lipid Membrane

We measured the conductance of bilayer lipid membranes of diphytanoylphosphatidylcholine induced by interaction with cubic magnetic nanoparticles (MNPs) of cobalt ferrite 12 and 27 nm in size and coated with a hydrophilic shell. The MNP coating is human serum albumin (HSA) or polyethylene glycol (PEG). The interaction of nanoparticles added to the bulk solution with the lipid bilayer causes the formation of metastable conductive pores, which, in turn, increases the integral conductance of the membranes. The increase in conductance with increasing MNP concentration was practically independent of the particle size. The dependence of the bilayer conductance on the concentration of PEG-coated MNPs was much weaker than that on the concentration with a shell of HSA. Analyzing the current traces, we believe that the conductive pores formed as a result of the interaction of nanoparticles with the membrane can change their size, remaining metastable. The form of multilevel current traces allows us to assume that there are several metastable pore states close in energy. The average radius of the putative cylindrical pores is in the range of 0.4-1.3 nm.

Expansion of thermometry in magnetic hyperthermia cancer therapy: antecedence and aftermath

Magnetic hyperthermia cancer therapy (MHCT) is a promising antitumor therapy based on the generation of heat by magnetic nanoparticles under the influence of an alternating-current magnetic field. However, an often-overlooked factor hindering the translation of MHCT to clinics is the inability to accurately monitor temperature, thereby leading to erroneous thermal control. It is significant to address 'thermometry' during magnetic hyperthermia because numerous factors are affected by the magnetic fields employed, rendering traditional thermometry methods unsuitable for temperature estimation. Currently, there is a dearth of literature describing appropriate techniques for thermometry during MHCT. This review offers a general outline of the various modes of conventional thermometry as well as cutting-edge techniques operating at cellular/nanoscale levels (nanothermometry) as prospective thermometers for MHCT in the future.

Nanoarchitectonics horizons: materials for life sciences

Nanoarchitectonics relies on the fabrication of materials at the atomic/molecular level to achieve the desired shape and function. Significant advances have been made in understanding the characteristics and spatial assemblies that contribute to material performance. Biomaterials undergo several changes when presented with various environmental cues. The ability to overcome such challenges, maintaining the integrity and effective functioning of native properties, can be regarded as a characteristic of a successful biomaterial. Control over the shape and efficacy of target materials can be tailored via various processes, like self-assembly, supramolecular chemistry, atomic/molecular manipulation, etc. Interplay between the physicochemical properties of materials and biomolecule recognition sites defines the structural rigidity in hierarchical structures. Materials including polymers, metal nanoparticles, nucleic acid systems, metal-organic frameworks, and carbon-based nanostructures can be viewed as promising prospects for developing biocompatible systems. This review discusses recent advances relating to such biomaterials for life science applications, where nanoarchitectonics plays a decisive role either directly or indirectly.

Shaping and Focusing Magnetic Field in the Human Body: State-of-the Art and Promising Technologies

In recent years, the usage of radio frequency magnetic fields for biomedical applications has increased exponentially. Several diagnostic and therapeutic methodologies exploit this physical entity such as, for instance, magnetic resonance imaging, hyperthermia with magnetic nanoparticles and transcranial magnetic stimulation. Within this framework, the magnetic field focusing and shaping, at different depths inside the tissue, emerges as one of the most important challenges from a technological point of view, since it is highly desirable for improving the effectiveness of clinical methodologies. In this review paper, we will first report some of the biomedical practices employing radio frequency magnetic fields, that appear most promising in clinical settings, explaining the underneath physical principles and operative procedures. Specifically, we direct the interest toward hyperthermia with magnetic nanoparticles and transcranial magnetic stimulation, together with a brief mention of magnetic resonance imaging. Additionally, we deeply review the technological solutions that have appeared so far in the literature to shape and control the radio frequency magnetic field distribution within biological tissues, highlighting human applications. In particular, volume and surface coils, together with the recent raise of metamaterials and metasurfaces will be reported. The present review manuscript can be useful to fill the actual gap in the literature and to serve as a guide for the physicians and engineers working in these fields.

Pharmacokinetics of magnetic iron oxide nanoparticles for medical applications

Magnetic iron oxide nanoparticles (MNPs) have been under intense investigation for at least the last five decades as they show enormous potential for many biomedical applications, such as biomolecule separation, MRI imaging and hyperthermia. Moreover, a large area of research on these nanostructures is concerned with their use as carriers of drugs, nucleic acids, peptides and other biologically active compounds, often leading to the development of targeted therapies. The uniqueness of MNPs is due to their nanometric size and unique magnetic properties. In addition, iron ions, which, along with oxygen, are a part of the MNPs, belong to the trace elements in the body. Therefore, after digesting MNPs in lysosomes, iron ions are incorporated into the natural circulation of this element in the body, which reduces the risk of excessive storage of nanoparticles. Still, one of the key issues for the therapeutic applications of magnetic nanoparticles is their pharmacokinetics which is reflected in the circulation time of MNPs in the bloodstream. These characteristics depend on many factors, such as the size and charge of MNPs, the nature of the polymers and any molecules attached to their surface, and other. Since the pharmacokinetics depends on the resultant of the physicochemical properties of nanoparticles, research should be carried out individually for all the nanostructures designed. Almost every year there are new reports on the results of studies on the pharmacokinetics of specific magnetic nanoparticles, thus it is very important to follow the achievements on this matter. This paper reviews the latest findings in this field. The mechanism of action of the mononuclear phagocytic system and the half-lives of a wide range of nanostructures are presented. Moreover, factors affecting clearance such as hydrodynamic and core size, core morphology and coatings molecules, surface charge and technical aspects have been described.

Serum Albumin for Magnetic Nanoparticles Coating

Magnetic nanoparticles (MNPs) have great potential in biochemistry and medical science. In particular, iron oxide nanoparticles have demonstrated a promising effect in various biomedical applications due to their high magnetic properties, large surface area, stability, and easy functionalization. However, colloidal stability, biocompatibility, and potential toxicity of MNPs in physiological environments are crucial for their in vivo application. In this context, many research articles focused on the possible procedures for MNPs coating to improve their physic-chemical and biological properties. This review highlights one viable fabrication strategy of biocompatible iron oxide nanoparticles using human serum albumin (HSA). HSA is mainly a transport protein with many functions in various fundamental processes. As it is one of the most abundant plasma proteins, not a single drug in the blood passes without its strength test. It influences the stability, pharmacokinetics, and biodistribution of different drug-delivery systems by binding or forming its protein corona on the surface. The development of albumin-based drug carriers is gaining increasing importance in the targeted delivery of cancer therapy. Considering this, HSA is a highly potential candidate for nanoparticles coating and theranostics area and can provide biocompatibility, prolonged blood circulation, and possibly resolve the drug-resistance cancer problem.

Biomedical Applications of Iron Oxide Nanoparticles: Current Insights Progress and Perspectives

The enormous development of nanomaterials technology and the immediate response of many areas of science, research, and practice to their possible application has led to the publication of thousands of scientific papers, books, and reports. This vast amount of information requires careful classification and order, especially for specifically targeted practical needs. Therefore, the present review aims to summarize to some extent the role of iron oxide nanoparticles in biomedical research. Summarizing the fundamental properties of the magnetic iron oxide nanoparticles, the review's next focus was to classify research studies related to applying these particles for cancer diagnostics and therapy (similar to photothermal therapy, hyperthermia), in nano theranostics, multimodal therapy. Special attention is paid to research studies dealing with the opportunities of combining different nanomaterials to achieve optimal systems for biomedical application. In this regard, original data about the synthesis and characterization of nanolipidic magnetic hybrid systems are included as an example. The last section of the review is dedicated to the capacities of magnetite-based magnetic nanoparticles for the management of oncological diseases.

Tailoring Interfacial Exchange Anisotropy in Hard-Soft Core-Shell Ferrite Nanoparticles for Magnetic Hyperthermia Applications

Magnetically hard-soft core-shell ferrite nanoparticles are synthesized using an organometallic decomposition method through seed-mediated growth. Two sets of core-shell nanoparticles (S1 and S2) with different shell (Fe3O4) thicknesses and similar core (CoFe2O4) sizes are obtained by varying the initial quantities of seed nanoparticles of size 6.0 ± 1.0 nm. The nanoparticles synthesized have average sizes of 9.5 ± 1.1 (S1) and 12.2 ± 1.7 (S2) nm with corresponding shell thicknesses of 3.5 and 6.1 nm. Magnetic properties are investigated under field-cooled and zero-field-cooled conditions at several temperatures and field cooling values. Magnetic heating efficiency for magnetic hyperthermia applications is investigated by measuring the specific absorption rate (SAR) in alternating magnetic fields at several field strengths and frequencies. The exchange bias is found to have a nonmonotonic and oscillatory relationship with temperature at all fields. SAR values of both core-shell samples are found to be considerably larger than that of the single-phase bare core particles. The effective anisotropy and SAR values are found to be larger in S2 than those in S1. However, the saturation magnetization displays the opposite behavior. These results are attributed to the occurrence of spin-glass regions at the core-shell interface of different amounts in the two samples. The novel outcome is that the interfacial exchange anisotropy of core-shell nanoparticles can be tailored to produce large effective magnetic anisotropy and thus large SAR values.

Stimuli-responsive nanomaterials for cancer treatment: boundaries, opportunities and applications

Small molecule drugs, including most chemotherapies, are rapidly degraded and/or eliminated from the body, which is why high doses of these drugs are necessary, potentially producing toxic effects. Several types of nanoparticles loaded with anti-cancer drugs have been designed to overcome the disadvantages of conventional therapies. Modified nanoparticles can circulate for a long time, thus improving the solubility and biodistribution of drugs. Furthermore, they also allow the controlled release of the payload once its target tissue has been reached. These mechanisms can reduce the exposure of healthy tissues to chemotherapeutics, since the drugs are only released in the presence of specific tumour stimuli. Overall, these properties can improve the effectiveness of treatments while reducing undesirable side effects. In this article, we review the recent advances in stimuli-responsive albumin, gold and magnetic nanostructures for controlled anti-cancer drug delivery. These nanostructures were designed to release drugs in response to different internal and external stimuli of the cellular environment, including pH, redox, light and magnetic fields. We also describe various examples of applications of these nanomaterials. Overall, we shed light on the properties, potential clinical translation and limitations of stimuli-responsive nanoparticles for cancer treatment.

An Integrated Microheater Array With Closed-Loop Temperature Regulation Based on Ferromagnetic Resonance of Magnetic Nanoparticles

Magnetic nanoparticles (MNP) can generate localized heat in response to an external alternating magnetic field, a unique capability that has enabled a wide range of biomedical applications. Compared with other heating mechanisms such as dielectric heating and ohmic heating, MNP-based magnetic heating offers superior material specificity and minimal damage to the surrounding environment since most biological systems are non-magnetic. This paper presents a first-of-its-kind fully integrated magnetic microheater array based on the ferromagnetic resonance of MNP at Gigahertz (GHz) microwave frequencies. Each microheater pixel consists of a stacked oscillator to actuate MNP with a high magnetic field intensity and an electro-thermal feedback loop for precise temperature regulation. The four-stacked/five-stacked oscillator achieves >19.5/26.5 V_pp measured RF output swing from 1.18 to 2.62 GHz while only occupying a single inductor footprint, which eliminates the need for additional RF power amplifiers for compact pixel size (0.6 mm × 0.7 mm) and high dc-to-RF energy efficiency (45%). The electro-thermal feedback loop senses the local temperature and enables closed-loop temperature regulation by controlling the biasing voltage of the stacked oscillator, achieving a measured maximum/RMS temperature error of 0.53/0.29 °C. In the localized heating demonstration, two PDMS membranes mixed with and without MNP are attached to the microheater array chip, respectively, and their surface temperatures are monitored by an infrared (IR) camera. Only the area above the inductor (∼0.03 mm²) is efficiently heated up to 43 °C for the MNP-PDMS membrane, while the baseline temperature stays <37.8 °C for the PDMS membrane without MNP.

An Overview of Micronanoswarms for Biomedical Applications

Micronanoswarms have attracted extensive attention worldwide due to their great promise in biomedical applications. The collective behaviors among thousands, or even millions, of tiny active agents indicate immense potential for benefiting the progress of clinical therapeutic and diagnostic methods. In recent years, with the development of smart materials, remote actuation modalities, and automatic control strategies, the motion dexterity, environmental adaptability, and functionality versatility of micronanoswarms are improved. Swarms can thus be designed as dexterous platforms inside living bodies to perform a multitude of tasks related to healthcare. Existing surveys summarize the design, functionalization, and biomedical applications of micronanorobots and the actuation and motion control strategies of micronanoswarms. This review presents the recent progress of micronanoswarms, aiming for biomedical applications. The recent advances on structural design of artificial, living, and hybrid micronanoswarms are summarized, and the biomedical applications that could be tackled using micronanoswarms are introduced, such as targeted drug delivery, hyperthermia, imaging and sensing, and thrombolysis. Moreover, potential challenges and promising trends of future developments are discussed. It is envisioned that the future success of these promising tools will have a significant impact on clinical treatment.

The Effect of pH and Buffer on Oligonucleotide Affinity for Iron Oxide Nanoparticles

Magnetic Fe3O4 nanoparticles (MNPs) have great potential in the nucleic acid delivery approach for therapeutic applications. Herein, the formation of a stable complex of iron oxide nanoparticles with oligonucleotides was investigated. Several factors, such as pH, buffer components, and oligonucleotides sequences, were chosen for binding efficiency studies and oligonucleotide binding constant calculation. Standard characterization techniques, such as dynamic light scattering, zeta potential, and transmission electron microscopy, provide MNPs coating and stability. The toxicity experiments were performed using lung adenocarcinoma A549 cell line and high reactive oxygen species formation with methylene blue assay. Fe3O4 MNPs complexes with oligonucleotides show high stability and excellent biocompatibility.

Exosome-based hybrid nanostructures for enhanced tumor targeting and hyperthermia therapy

Recently, natural exosomes have attracted attention as an ideal drug carrier to overcome the limitations of existing drug delivery systems which are toxicity induction and low cancer-targeting performance. In this study, we propose an exosome-based hybrid nanostructure (EHN) with improved targeting ability and therapeutic efficacy against colorectal cancer by using exosomes isolated from the tumor cell line as a drug carrier. The proposed EHN can have high biocompatibility by using exosomes, a biologically derived material, and show improved targeting performance by adding a tumor-targeting ligand (folic acid). In addition, the proposed EHN is capable of chemotherapy because doxorubicin, an anticancer drug, is encapsulated by the exosome with high efficiency, and it can induce hyperthermia therapy because of the magnetic nanoparticles (MNPs) attached to the surface of exosomes. Through in vitro and in vivo experiments using a xenograft tumor mouse model, it was confirmed that the proposed EHN could exhibit increased apoptosis and excellent tumor growth inhibition ability. Therefore, the proposed EHN is expected to overcome the limitations of existing drug delivery systems and be utilized as an effective drug delivery system in cancer treatment.

Specific Absorption Rate Dependency on the Co2+ Distribution and Magnetic Properties in CoxMn1-xFe2O4 Nanoparticles

Mixed ferrite nanoparticles with compositions CoxMn1-xFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) were synthesized by a simple chemical co-precipitation method. The structure and morphology of the nanoparticles were obtained by X-ray diffraction (XRD), transmission electron microscope (TEM), Raman spectroscopy, and Mössbauer spectroscopy. The average crystallite sizes decreased with increasing x, starting with 34.9 ± 0.6 nm for MnFe2O4 (x = 0) and ending with 15.0 ± 0.3 nm for CoFe2O4 (x = 1.0). TEM images show an edge morphology with the majority of the particles having cubic geometry and wide size distributions. The mixed ferrite and CoFe2O4 nanoparticles have an inverse spinel structure indicated by the splitting of A1g peak at around 620 cm-1 in Raman spectra. The intensity ratios of the A1g(1) and A1g(2) peaks indicate significant redistribution of Co2+ and Fe3+ cations among tetrahedral and octahedral sites in the mixed ferrite nanoparticles. Magnetic hysterics loops show that all the particles possess significant remnant magnetization and coercivity at room temperature. The mass-normalized saturation magnetization is highest for the composition with x = 0.8 (67.63 emu/g), while CoFe2O4 has a value of 65.19 emu/g. The nanoparticles were PEG (poly ethylene glycol) coated and examined for the magneto thermic heating ability using alternating magnetic field. Heating profiles with frequencies of 333.45, 349.20, 390.15, 491.10, 634.45, and 765.95 kHz and 200, 250, 300, and 350 G field amplitudes were obtained. The composition with x = 0.2 (Co0.2Mn0.8Fe2O4) with saturation magnetization 57.41 emu/g shows the highest specific absorption rate (SAR) value of 190.61 W/g for 10 mg/mL water dispersions at a frequency of 765.95 kHz and 350 G field strength. The SAR values for the mixed ferrite and CoFe2O4 nanoparticles increase with increasing concentration of particle dispersions, whereas for MnFe2O4, nanoparticles decrease with increasing the concentration of particle dispersions. SARs obtained for Co0.2Mn0.8Fe2O4 and CoFe2O4 nanoparticles fixed in agar ferrogel dispersions at frequency of 765.95 kHz and 350 G field strength are 140.35 and 67.60 W/g, respectively. This study shows the importance of optimizing the occupancy of Co2+ among tetrahedral and octahedral sites of the spinel system, concentration of the magnetic nanoparticle dispersions, and viscosity of the surrounding medium on the magnetic properties and heating efficiencies.

Hybrid System for Local Drug Delivery and Magnetic Hyperthermia Based on SPIONs Loaded with Doxorubicin and Epirubicin

Cancer is one of the most common causes of death worldwide, thus new solutions in anticancer therapies are highly sought after. In this work, superparamagnetic iron oxide nanoparticles (SPIONs) conjugated with anticancer drugs are synthesized and investigated as potential magnetic drug nanocarriers for local drug delivery and mild magnetic hyperthermia. We have obtained a hybrid system loaded with holmium and anticancer drugs and thoroughly studied it with respect to the size, morphology, surface modifications and magnetic properties, and interactions with the model of biological membranes, cytotoxicity. We present that nanoparticles having a round shape and size 15 nm are successfully stabilized to avoid their agglomeration and modified with doxorubicin or epirubicin within a controlled way. The number of drugs loaded into the SPIONs was confirmed with thermogravimetry. The hybrid based on SPIONs was investigated in touch with model biological membranes within the Langmuir-Blodgett technique, and results show that modified SPION interacts effectively with them. Results obtained with magnetic hyperthermia and biological studies confirm the promising properties of the hybrid towards future cancer cell treatment.

Trends in the development of innovative nanobiocatalysts and their application in biocatalytic transformations

The ever-growing demand for cost-effective and innocuous biocatalytic transformations has prompted the rational design and development of robust biocatalytic tools. Enzyme immobilization technology lies in the formation of cooperative interactions between the tailored surface of the support and the enzyme of choice, which result in the fabrication of tremendous biocatalytic tools with desirable properties, complying with the current demands even on an industrial level. Different nanoscale materials (organic, inorganic, and green) have attracted great attention as immobilization matrices for single or multi-enzymatic systems. Aiming to unveil the potentialities of nanobiocatalytic systems, we present distinct immobilization strategies and give a thorough insight into the effect of nanosupports specific properties on the biocatalysts' structure and catalytic performance. We also highlight the development of nanobiocatalysts for their incorporation in cascade enzymatic processes and various types of batch and continuous-flow reactor systems. Remarkable emphasis is given on the application of such nanobiocatalytic tools in several biocatalytic transformations including bioremediation processes, biofuel production, and synthesis of bioactive compounds and fine chemicals for the food and pharmaceutical industry.