Brain and bone cancer targeting by a ferrofluid composed of superparamagnetic iron-oxide/silica/carbon nanoparticles (earthicles)

Cytoskeleton-modulating nanomaterials and their therapeutic potentials

The cytoskeleton, an intricate network of protein fibers within cells, plays a pivotal role in maintaining cell shape, enabling movement, and facilitating intracellular transport. Its involvement in various pathological states, ranging from cancer proliferation and metastasis to the progression of neurodegenerative disorders, underscores its potential as a target for therapeutic intervention. The exploration of nanotechnology in this realm, particularly the use of nanomaterials for cytoskeletal modulation, represents a cutting-edge approach with the promise of novel treatments. Inorganic nanomaterials, including those derived from gold, metal oxides, carbon, and black phosphorus, alongside organic variants such as peptides and proteins, are at the forefront of this research. These materials offer diverse mechanisms of action, either by directly interacting with cytoskeletal components or by influencing cellular signaling pathways that, in turn, modulate the cytoskeleton. Recent advancements have introduced magnetic field-responsive and light-responsive nanomaterials, which allow for targeted and controlled manipulation of the cytoskeleton. Such precision is crucial in minimizing off-target effects and enhancing therapeutic efficacy. This review explores the importance of research into cytoskeleton-targeting nanomaterials for developing therapeutic interventions for a range of diseases. It also addresses the progress made in this field, the challenges encountered, and future directions for using nanomaterials to modulate the cytoskeleton. The continued exploration of nanomaterials for cytoskeleton modulation holds great promise for advancing therapeutic strategies against a broad spectrum of diseases, marking a significant step forward in the intersection of nanotechnology and medicine.

Current status and research progress of minimally invasive treatment of glioma

Glioma has a high malignant degree and poor prognosis, which seriously affects the prognosis of patients. Traditional treatment methods mainly include craniotomy tumor resection, postoperative radiotherapy and chemotherapy. Although above methods have achieved remarkable curative effect, they still have certain limitations and adverse reactions. With the introduction of the concept of minimally invasive surgery and its clinical application as well as the development and progress of imaging technology, minimally invasive treatment of glioma has become a research hotspot in the field of neuromedicine, including photothermal treatment, photodynamic therapy, laser-induced thermal theraphy and TT-Fields of tumor. These therapeutic methods possess the advantages of precision, minimally invasive, quick recovery and significant curative effect, and have been widely used in clinical practice. The purpose of this review is to introduce the progress of minimally invasive treatment of glioma in recent years and the achievements and prospects for the future.

Learning to Control a Three-Dimensional Ferrofluidic Robot

In recent years, ferrofluids have found increased popularity as a material for medical applications, such as ocular surgery, gastrointestinal surgery, and cancer treatment, among others. Ferrofluidic robots are multifunctional and scalable, exhibit fluid properties, and can be controlled remotely; thus, they are particularly advantageous for such medical tasks. Previously, ferrofluidic robot control has been achieved via the manipulation of handheld permanent magnets or in current-controlled electromagnetic fields resulting in two-dimensional position and shape control and three-dimensional (3D) coupled position-shape or position-only control. Control of ferrofluidic liquid droplet robots poses a unique challenge where model-based control has been shown to be computationally limiting. Thus, in this study, a model-free control method is chosen, and it is shown that the task of learning optimal control parameters for ferrofluidic robot control can be performed using machine learning. Particularly, we explore the use of Bayesian optimization to find optimal controller parameters for 3D pose control of a ferrofluid droplet: its centroid position, stretch direction, and stretch radius. We demonstrate that the position, stretch direction, and stretch radius of a ferrofluid droplet can be independently controlled in 3D with high accuracy and precision, using a simple control approach. Finally, we use ferrofluidic robots to perform pick-and-place, a lab-on-a-chip pH test, and electrical switching, in 3D settings. The purpose of this research is to expand the potential of ferrofluidic robots by introducing full pose control in 3D and to showcase the potential of this technology in the areas of microassembly, lab-on-a-chip, and electronics. The approach presented in this research can be used as a stepping-off point to incorporate ferrofluidic robots toward future research in these areas.

Biocompatible Ferrofluid-Based Millirobot for Tumor Photothermal Therapy in Near-Infrared-II Window

Ferrofluidic robots with excellent deformability and controllability have been intensively studied recently. However, most of these studies are in vitro and the use of ferrofluids for in vivo medicinal applications remains a big challenge. The application of ferrofluidic robots to the body requires the solution of many key problems. In this study, biocompatibility, controllability, and tumor-killing efficacy are considered when creating a ferrofluid-based millirobot for in vivo tumor-targeted therapy. For biocompatibility problems, corn oil is used specifically for the ferrofluid robot. In addition, a control system is built that enables a 3D magnetic drive to be implemented in complex biological media. Using the photothermal conversion property of 1064 nm, the ferrofluid robot can kill tumor cells in vitro; inhibit tumor volume, destroy the tumor interstitium, increase tumor cell apoptosis, and inhibit tumor cell proliferation in vivo. This study provides a reference for ferrofluid-based millirobots to achieve targeted therapies in vivo.

Enhanced Biomimetics of Three-Dimensional Osteosarcoma Models: A Scoping Review

This scoping review evaluated 3D osteosarcoma (OS) models' biomimicry, examining their ability to mimic the tumour microenvironment (TME) and their drug sensitivity. Adhering to PRISMA-ScR guidelines, the systematic search revealed 293 studies, with 70 selected for final analysis. Overall, 64% of 3D OS models were scaffold-based, compared to self-generated spheroid models. Scaffolds generated using native matrix were most common (42%) with collagen I/hydroxyapatite predominating. Both scaffold-based and scaffold-free models were used equally for drug screening. The sensitivity of cancer cells in 3D was reported to be lower than that of cells in 2D in ~90% of the drug screening studies. This correlates with the observed upregulation of drug resistance. OS cells cultured in extracellular matrix (ECM)-mimetic scaffolds and native biomaterials were more resistant than cells in 2D. Co-cultures of OS and stromal cells in 3D models enhanced osteogenic differentiation, ECM remodelling, mineralisation, and angiogenesis, suggesting that tumour-stroma crosstalk promotes disease progression. Seven studies demonstrated selective toxicity of chemotherapeutics towards OS cells while sparing stromal cells, providing useful evidence for developing biomimetic tumour-stroma models to test selective drug toxicity. In conclusion, this review highlights the need to enhance biomimicry in 3D OS models for TME recapitulation, especially in testing novel therapeutics. Future research should explore innovative 3D biomimetic models, biomaterials, and advancements in personalised medicine.

Simple method for quantification of metal-based particles in biopsy samples of patients with long bone implants - Pilot study

The presence of particles fixed in tissue samples due to implant degradation or disintegration plays an important role in post-operative complications. The ability to determine the size, shape, chemical composition and, above all, the number of these particles can be used in many areas of medicine. This study presents a novel, simple metal-based particle detection method using scanning electron microscopy with energy dispersive spectrometer (SEM-EDS). The presence of metal particles in biopsy specimens from long bone nail-fixated implants (10 patients with titanium steel nails and 10 patients with stainless steel nails) was studied. The samples were analysed using automated area analysis based on image binarization and brightness to 255 grayscale. The results were supplemented with histological data and statistically analysed. The method based on the software used was found to be accurate and easy to use and, thus, appears to be very suitable for particle detection in similar samples.

Research Progress of Nanomaterials in Chemotherapy of Osteosarcoma

Osteosarcoma (OS) is a common malignant bone tumor that occurs mostly in children and adolescents. At present, surgery after chemotherapy or postoperative adjuvant chemotherapy is the main treatment plan. However, the efficacy of chemotherapeutic drugs is limited by the occurrence of chemotherapeutic resistance, toxicity to normal cells, poor pharmacokinetic performance, and drug delivery failure. The delivery of chemotherapy drugs to the bone to treat OS may fail for a variety of reasons, such as a lack of selectivity for OS cells, initial sudden release, short-term release, and the presence of biological barriers (such as the blood-bone marrow barrier). Nanomaterials are new materials with at least one dimension on the nanometer scale (1-100 nm) in three-dimensional space. These materials have the ability to penetrate biological barriers and can accumulate preferentially in tumor cells. Studies have shown that the effective combination of nanomaterials and traditional chemotherapy can significantly improve the therapeutic effect. Therefore, this article reviews the latest research progress on the use of nanomaterials in OS chemotherapy.

Influence of a bias dc field and an ac field amplitude on the dynamic susceptibility of a moderately concentrated ferrofluid

In this paper, we study the effect of a bias dc field on the dynamic response of a moderately concentrated ferrofluid to an ac magnetic field of arbitrary amplitude. The ferrofluid is modeled by an ensemble of interacting moving magnetic particles; the reaction of particle magnetic moments to ac and dc magnetic fields occurs according to the Brownian mechanism; and the ac and dc magnetic fields are parallel. Based on a numerical solution of the Fokker-Planck equation for the probability density of the orientation of the magnetic moment of a random magnetic particle, dynamic magnetization and susceptibility are determined and analyzed for various values of the ac field amplitude, the dc field strength, and the intensity of dipole-dipole interactions. It is shown that the system's magnetic response is formed under the influence of competing interactions, such as dipole-dipole, dipole-ac field, and dipole-dc field interactions. When the energies of these interactions are comparable, unexpected effects are observed: the system's susceptibility can either increase or decrease with increasing ac field amplitude. This behavior is associated with the formation of nose-to-tail dipolar structures under the action of the dc field, which can hinder or promote the system's dynamic response to the ac field. The obtained results provide a theoretical basis for predicting the dynamic properties of ferrofluids to improve their use in biomedical applications, such as, in magnetic induction hyperthermia.

Cell-Membrane-Coated and Cell-Penetrating Peptide-Conjugated Trimagnetic Nanoparticles for Targeted Magnetic Hyperthermia of Prostate Cancer Cells

Prostate malignancy represents the second leading cause of cancer-specific death among the male population worldwide. Herein, enhanced intracellular magnetic fluid hyperthermia is applied in vitro to treat prostate cancer (PCa) cells with minimum invasiveness and toxicity and highly specific targeting. We designed and optimized novel shape-anisotropic magnetic core-shell-shell nanoparticles (i.e., trimagnetic nanoparticles - TMNPs) with significant magnetothermal conversion following an exchange coupling effect to an external alternating magnetic field (AMF). The functional properties of the best candidate in terms of heating efficiency (i.e., Fe₃O₄@Mn_0.5Zn_0.5Fe₂O₄@CoFe₂O₄) were exploited following surface decoration with PCa cell membranes (CM) and/or LN1 cell-penetrating peptide (CPP). We demonstrated that the combination of biomimetic dual CM-CPP targeting and AMF responsiveness significantly induces caspase 9-mediated apoptosis of PCa cells. Furthermore, a downregulation of the cell cycle progression markers and a decrease of the migration rate in surviving cells were observed in response to the TMNP-assisted magnetic hyperthermia, suggesting a reduction in cancer cell aggressiveness.

Metal and Metal Oxides Nanoparticles and Nanosystems in Anticancer and Antiviral Theragnostic Agents

The development of antiviral treatment and anticancer theragnostic agents in recent decades has been associated with nanotechnologies, and primarily with inorganic nanoparticles (INPs) of metal and metal oxides. The large specific surface area and its high activity make it easy to functionalize INPs with various coatings (to increase their stability and reduce toxicity), specific agents (allowing retention of INPs in the affected organ or tissue), and drug molecules (for antitumor and antiviral therapy). The ability of magnetic nanoparticles (MNPs) of iron oxides and ferrites to enhance proton relaxation in specific tissues and serve as magnetic resonance imaging contrast agents is one of the most promising applications of nanomedicine. Activation of MNPs during hyperthermia by an external alternating magnetic field is a promising method for targeted cancer therapy. As therapeutic tools, INPs are promising carriers for targeted delivery of pharmaceuticals (either anticancer or antiviral) via magnetic drug targeting (in case of MNPs), passive or active (by attaching high affinity ligands) targeting. The plasmonic properties of Au nanoparticles (NPs) and their application for plasmonic photothermal and photodynamic therapies have been extensively explored recently in tumor treatment. The Ag NPs alone and in combination with antiviral medicines reveal new possibilities in antiviral therapy. The prospects and possibilities of INPs in relation to magnetic hyperthermia, plasmonic photothermal and photodynamic therapies, magnetic resonance imaging, targeted delivery in the framework of antitumor theragnostic and antiviral therapy are presented in this review.

Micronesian maritime piloting charts as bioimaging proxies for the rescue of cells on the apoptotic trajectory

This interdisciplinary study falls within the realm of ethnoscience thanks to its resorting to the scientific methods behind the Micronesian canoe voyaging in search of bioimaging tools for the early prediction of cell fate in response to a therapy. Two distinct indigenous methods for navigation across the ocean were assessed as bridges for correlating (i) the interaction of oceanic swells near atolls with the way microcurrents in the cell culture dish may shape the morphology of cells, and (ii) the spatial arrangement of cultured cells with the canoe voyaging from one island to the next. Both methods effectively predicted the cell fate at early time points in the treatment with superparamagnetic nanoparticles, when the adverse effects were still reversible and not apparent yet at the levels of cell morphology, proliferation rate or confluence. The mattang chart, the most fundamental and theoretical of navigational devices used in the Marshallese seafaring tradition, was used to measure subtle morphological changes occurring in cells due to the treatment. The cells subjected to the treatment were consistently withdrawing their bodies from the areas of intense swell interaction activity on the superimposed mattangs. Given that the cytoskeletal microfilaments defining the features of control cells were largely filling up these areas, this metric proved useful for deducing the course of the treatment at its early stages. The same deduction was proven feasible with the use of a Carolinian navigational technique based on the concept of the etak, in which case the distances traversable between cells in a population subjected to the treatment were divisible to a significantly higher number of etaks than the same distances in the population of control cells. Therefore, treating cells and their nuclei as analogous to Pacific atolls navigable to and fro with the use of imaginary microscopic canoes and the navigational principles native to the Marshall and the Caroline Islands proves as a clever, but also very effective cell fate prediction approach, which various branches of biomedical science could take advantage of. These practical benefits notwithstanding, this conceptual study was performed primarily with a goal to spark the interest in studying these and other ancient ethnoscientific inventions as potential addenda to the broad repertoire of techniques used in biomedical and other sciences to combat some of their greatest challenges.

Glioma diagnosis and therapy: Current challenges and nanomaterial-based solutions

Glioma is often referred to as one of the most dreadful central nervous system (CNS)-specific tumors with rapidly-proliferating cancerous glial cells, accounting for nearly half of the brain tumors at an annual incidence rate of 30-80 per a million population. Although glioma treatment remains a significant challenge for researchers and clinicians, the rapid development of nanomedicine provides tremendous opportunities for long-term glioma therapy. However, several obstacles impede the development of novel therapeutics, such as the very tight blood-brain barrier (BBB), undesirable hypoxia, and complex tumor microenvironment (TME). Several efforts have been dedicated to exploring various nanoformulations for improving BBB permeation and precise tumor ablation to address these challenges. Initially, this article briefly introduces glioma classification and various pathogenic factors. Further, currently available therapeutic approaches are illustrated in detail, including traditional chemotherapy, radiotherapy, and surgical practices. Then, different innovative treatment strategies, such as tumor-treating fields, gene therapy, immunotherapy, and phototherapy, are emphasized. In conclusion, we summarize the article with interesting perspectives, providing suggestions for future glioma diagnosis and therapy improvement.

Overcoming the blood–brain barrier for the therapy of malignant brain tumor: current status and prospects of drug delivery approaches

Besides the broad development of nanotechnological approaches for cancer diagnosis and therapy, currently, there is no significant progress in the treatment of different types of brain tumors. Therapeutic molecules crossing the blood–brain barrier (BBB) and reaching an appropriate targeting ability remain the key challenges. Many invasive and non-invasive methods, and various types of nanocarriers and their hybrids have been widely explored for brain tumor treatment. However, unfortunately, no crucial clinical translations were observed to date. In particular, chemotherapy and surgery remain the main methods for the therapy of brain tumors. Exploring the mechanisms of the BBB penetration in detail and investigating advanced drug delivery platforms are the key factors that could bring us closer to understanding the development of effective therapy against brain tumors. In this review, we discuss the most relevant aspects of the BBB penetration mechanisms, observing both invasive and non-invasive methods of drug delivery. We also review the recent progress in the development of functional drug delivery platforms, from viruses to cell-based vehicles, for brain tumor therapy. The destructive potential of chemotherapeutic drugs delivered to the brain tumor is also considered. This review then summarizes the existing challenges and future prospects in the use of drug delivery platforms for the treatment of brain tumors.

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

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

Drug-delivery nanoparticles for bone-tissue and dental applications

The use of nanoparticles as biomaterials with applications in the biomedical field is growing every day. These nanomaterials can be used as contrast imaging agents, combination therapy agents, and targeted delivery systems in medicine and dentistry. Usually, nanoparticles are found as synthetic or natural organic materials, such as hydroxyapatite, polymers, and lipids. Besides that, they are could also be inorganic, for instance, metallic or metal-oxide-based particles. These inorganic nanoparticles could additionally present magnetic properties, such as superparamagnetic iron oxide nanoparticles. The use of nanoparticles as drug delivery agents has many advantages, for they help diminish toxicity effects in the body since the drug dose reduces significantly, increases drugs biocompatibility, and helps target drugs to specific organs. As targeted-delivery agents, one of the applications uses nanoparticles as drug delivery particles for bone-tissue to treat cancer, osteoporosis, bone diseases, and dental treatments such as periodontitis. Their application as drug delivery agents requires a good comprehension of the nanoparticle properties and composition, alongside their synthesis and drug attachment characteristics. Properties such as size, shape, core-shell designs, and magnetic characteristics can influence their behavior inside the human body and modify magnetic properties in the case of magnetic nanoparticles. Based on that, many different studies have modified the synthesis methods for these nanoparticles and developed composite systems for therapeutics delivery, adapting, and improving magnetic properties, shell-core designs, and particle size and nanosystems characteristics. This review presents the most recent studies that have been presented with different nanoparticle types and structures for bone and dental drug delivery.

Inorganic Nanoparticles in Bone Healing Applications

Modern biomedicine aims to develop integrated solutions that use medical, biotechnological, materials science, and engineering concepts to create functional alternatives for the specific, selective, and accurate management of medical conditions. In the particular case of tissue engineering, designing a model that simulates all tissue qualities and fulfills all tissue requirements is a continuous challenge in the field of bone regeneration. The therapeutic protocols used for bone healing applications are limited by the hierarchical nature and extensive vascularization of osseous tissue, especially in large bone lesions. In this regard, nanotechnology paves the way for a new era in bone treatment, repair and regeneration, by enabling the fabrication of complex nanostructures that are similar to those found in the natural bone and which exhibit multifunctional bioactivity. This review aims to lay out the tremendous outcomes of using inorganic nanoparticles in bone healing applications, including bone repair and regeneration, and modern therapeutic strategies for bone-related pathologies.

A bone-targeting drug delivery vehicle of a metal-organic framework conjugate with zoledronate combined with photothermal therapy for tumor inhibition in cancer bone metastasis

Chemotherapy is a conventional treatment method for metastatic bone cancer, but it has limitations, such as lower drug-targeting of bone tissues and serious side effects. Bone metastasis almost always occurs in advanced cancer, and most patients in this period have strong drug resistance, which further worsens the curative effect. To address the above-mentioned difficulties, a drug delivery platform is proposed in this paper that accomplishes the bone-targeting of drugs to efficiently inhibit tumors. First, the anti-cancer drugs 5-fluorouracil (5-Fu) and indocyanine green (ICG) were loaded into a zeolitic imidazolate framework (ZIF-90) to form 5-Fu/ICG@ZIF-90. Polyethylene glycol with zoledronic acid (ZOL) was encapsulated using 5-Fu/ICG@ZIF-90 to synthesize 5-Fu/ICG@ZIF-90-PEG-ZOL nanoparticles, which showed dimensional stability, good thermal stability, and bone-targeting ability. Second, the in vitro anti-cancer activity of the designed platform was investigated using cytotoxicity, apoptosis, live-dead staining, cell cycle, and cell ultrathin section analysis. The results indicated that the nanoparticles inhibited MCF-7 cell activity when chemotherapy was combined with PTT. Finally, H&E staining and TUNEL detection were performed in mouse organs and tumors. The nanoparticles combined with photothermal therapy (PTT) and triggered by near-infrared irradiation induce apoptosis of tumor cells in vivo, displaying a better efficacy of combined chemotherapy and photothermal therapy. Experiments conducted on the 5-Fu/ICG@ZIF-90-PEG-ZOL nanoparticles demonstrated their promising performance for cancer bone metastasis inhibition.

Superparamagnetic iron oxide nanoparticles for magnetic hyperthermia: Recent advancements, molecular effects, and future directions in the omics era

Superparamagnetic iron oxide nanoparticles have attracted attention in the biomedical field thanks to their ability to prompt hyperthermia in response to an alternated magnetic field. Hyperthermia is well-known for inducing...

Carbon nanomaterials as emerging nanotherapeutic platforms to tackle the rising tide of cancer - A review

Cancer has become one of the main reasons for human death in recent years. Around 18 million new cancer cases and approximately 9.6 million deaths from cancer reported in 2018, and the annual number of cancer cases will have increased to 22 million in the next two decades. These alarming facts have rekindled researchers' attention to develop and apply different approaches for cancer therapy. Unfortunately, most of the applied methods for cancer therapy not only have adverse side effects like toxicity and damage of healthy cells but also have a short lifetime. To this end, introducing innovative and effective methods for cancer therapy is vital and necessary. Among different potential materials, carbon nanomaterials can cope with the rising threats of cancer. Due to unique physicochemical properties of different carbon nanomaterials including carbon, fullerene, carbon dots, graphite, single-walled carbon nanotube and multi-walled carbon nanotubes, they exhibit possibilities to address the drawbacks for cancer therapy. Carbon nanomaterials are prodigious materials due to their ability in drug delivery or remedial of small molecules. Functionalization of carbon nanomaterials can improve the cancer therapy process and decrement the side effects. These exceptional traits make carbon nanomaterials as versatile and prevalent materials for application in cancer therapy. This article spotlights the recent findings in cancer therapy using carbon nanomaterials (2015-till now). Different types of carbon nanomaterials and their utilization in cancer therapy were highlighted. The plausible mechanisms for the action of carbon nanomaterials in cancer therapy were elucidated and the advantages and disadvantages of each material were also illustrated. Finally, the current problems and future challenges for cancer therapy based on carbon nanomaterials were discussed.

Dynamic magnetic susceptibility of a ferrofluid: The influence of interparticle interactions and ac field amplitude

Based on numerical results of dynamic susceptibility, a simple theory of the dynamic response of a ferrofluid to an ac magnetic field is obtained that includes both the effects of interparticle dipole-dipole interactions and the dependence on field amplitude. Interparticle interactions are incorporated in the theory using the so-called modified mean-field approach. The new theory has the following important characteristics: in the noninteracting regime at a weak ac field, it gives the correct single-particle Debye theory results; it expands the applicability of known theories valid for high concentrations [Ivanov, Zverev, and Kantorovich, Soft Matter 12, 3507 (2016)10.1039/C5SM02679B] or large values of ac field amplitudes [Yoshida and Enpuku, Jpn. J. Appl. Phys. 48, 127002 (2009)10.1143/JJAP.48.127002], in accordance with their applicability. The susceptibility spectra are analyzed in detail. It is demonstrated that interparticle dipole-dipole interactions and an increase in field amplitude have an opposite effect on the dynamic response of ferrofluids, so that at certain field amplitudes, relaxation processes in the system of interacting particles are determined by the characteristic relaxation times for an ideal paramagnetic gas. The new theory correctly predicts the dynamic susceptibility and characteristic relaxation times of a ferrofluid at high ac field amplitudes as long as the Langevin susceptibility χ_{L}≲1, which is a complex characteristic of ferrofluid density and the intensity of interparticle dipole-dipole interactions.

Green Metallic Nanoparticles for Cancer Therapy: Evaluation Models and Cancer Applications

Metal-based nanoparticles are widely used to deliver bioactive molecules and drugs to improve cancer therapy. Several research works have highlighted the synthesis of gold and silver nanoparticles by green chemistry, using biological entities to minimize the use of solvents and control their physicochemical and biological properties. Recent advances in evaluating the anticancer effect of green biogenic Au and Ag nanoparticles are mainly focused on the use of conventional 2D cell culture and in vivo murine models that allow determination of the half-maximal inhibitory concentration, a critical parameter to move forward clinical trials. However, the interaction between nanoparticles and the tumor microenvironment is not yet fully understood. Therefore, it is necessary to develop more human-like evaluation models or to improve the existing ones for a better understanding of the molecular bases of cancer. This review provides recent advances in biosynthesized Au and Ag nanoparticles for seven of the most common and relevant cancers and their biological assessment. In addition, it provides a general idea of the in silico, in vitro, ex vivo, and in vivo models used for the anticancer evaluation of green biogenic metal-based nanoparticles.

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

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

Ferromagnetic Liquid Droplet on a Superhydrophobic Surface for the Transduction of Mechanical Energy to Electricity Based on Electromagnetic Induction

Ferromagnetic liquids undergo reversible magnetization changes upon varying external magnetic field levels. The movement of ferromagnetic liquid droplets across a coil under an external magnetic field holds promise as an energy transducer from mechanical force to electricity; however, it suffers from an adhesive issue between the ferromagnetic liquid and the solid pedestal. We introduce a superhydrophobic support that uses antiwetting surfaces to remarkably reduce adhesion during the movement of ferromagnetic liquid droplets. Maxwell numerical simulation was utilized to analyze the working mechanism and improve further electrical outputs. By controlling the droplet size, the strength of the magnetic bottom and the tilting speed of the test condition, we generated a ferromagnetic liquid droplet-based superhydrophobic magnetoelectric energy transducer (FLD-SMET) that can convert vibrational energy to electricity. When a 100 μL ferromagnetic liquid droplet was used for FLD-SMET under a 13 mT magnetic field, an electrical voltage response of 280 μV and electrical current response of ∼7.5 μA were generated using a shaking machine with a tilting speed of 9.5°/s. We thus show that such a device can serve as a self-powered light buoy floating on a water surface. Our study presents an applied concept for the design of droplet-based energy harvesters to convert surrounding vibrational energy to electricity.

Advanced biomedical applications of iron oxide nanostructures based ferrofluids

Ferrofluids or magnetic nanofluids are highly stable colloidal suspensions of magnetic nanoparticles (NPs) dispersed into various base fluids. These stable ferrofluids possess high thermal conductivity, improved thermo-physical properties, higher colloidal stability, good magnetic properties, and biocompatibility, which are the primary driving forces behind their excellent performance, and thus enable them to be used for a wide range of practical applications. The most studied and advanced ferrofluids are based on iron oxide nanostructures especially NPs, because of their easy and large-scale synthesis at low costs. Although in the last decade, several review articles are available on ferrofluids but mainly focused on preparations, properties, and a specific application. Hence, a collective and comprehensive review article on the recent progress of iron oxide nanostructures based ferrofluids for advanced biomedical applications is undeniably required. In this review, the state of the art of biomedical applications is presented and critically analyzed with a special focus on hyperthermia, drug delivery/nanomedicine, magnetic resonance imaging, and magnetic separation of cells. This review article provides up-to-date information related to the technological advancements and emerging trends in iron oxide nanostructures based ferrofluids research focused on advanced biomedical applications. Finally, conclusions and outlook of iron oxide nanostructures based ferrofluids research for biomedical applications are presented.

Smart Cargo Delivery System based on Mesoporous Nanoparticles for Bone Disease Diagnosis and Treatment

Bone diseases constitute a major issue for modern societies as a consequence of progressive aging. Advantages such as open mesoporous channel, high specific surface area, ease of surface modification, and multifunctional integration are the driving forces for the application of mesoporous nanoparticles (MNs) in bone disease diagnosis and treatment. To achieve better therapeutic effects, it is necessary to understand the properties of MNs and cargo delivery mechanisms, which are the foundation and key in the design of MNs. The main types and characteristics of MNs for bone regeneration, such as mesoporous silica (mSiO2 ), mesoporous hydroxyapatite (mHAP), mesoporous calcium phosphates (mCaPs) are introduced. Additionally, the relationship between the cargo release mechanisms and bone regeneration of MNs-based nanocarriers is elucidated in detail. Particularly, MNs-based smart cargo transport strategies such as sustained cargo release, stimuli-responsive (e.g., pH, photo, ultrasound, and multi-stimuli) controllable delivery, and specific bone-targeted therapy for bone disease diagnosis and treatment are analyzed and discussed in depth. Lastly, the conclusions and outlook about the design and development of MNs-based cargo delivery systems in diagnosis and treatment for bone tissue engineering are provided to inspire new ideas and attract researchers' attention from multidisciplinary areas spanning chemistry, materials science, and biomedicine.

Carbon-coated Fe3O4 core-shell super-paramagnetic nanoparticle-based ferrofluid for heat transfer applications

Herein, we report the investigation of the electrical and thermal conductivity of Fe₃O₄ and Fe₃O₄@carbon (Fe₃O₄@C) core-shell nanoparticle (NP)-based ferrofluids. Different sized Fe₃O₄ NPs were synthesized via a chemical co-precipitation method followed by carbon coating as a shell over the Fe₃O₄ NPs via the hydrothermal technique. The average particle size of Fe₃O₄ NPs and Fe₃O₄@C core-shell NPs was found to be in the range of ∼5-25 nm and ∼7-28 nm, respectively. The thickness of the carbon shell over the Fe₃O₄ NPs was found to be in the range of ∼1-3 nm. The magnetic characterization revealed that the as-synthesized small average-sized Fe₃O₄ NPs (ca. 5 nm) and Fe₃O₄@C core-shell NPs (ca. 7 nm) were superparamagnetic in nature. The electrical and thermal conductivities of Fe₃O₄ NPs and Fe₃O₄@C core-shell NP-based ferrofluids were measured using different concentrations of NPs and with different sized NPs. Exceptional results were obtained, where the electrical conductivity was enhanced up to ∼3222% and ∼2015% for Fe₃O₄ (ca. 5 nm) and Fe₃O₄@C core-shell (ca. 7 nm) NP-based ferrofluids compared to the base fluid, respectively. Similarly, an enhancement in the thermal conductivity of ∼153% and ∼116% was recorded for Fe₃O₄ (ca. 5 nm) and Fe₃O₄@C core-shell (ca. 7 nm) NPs, respectively. The exceptional enhancement in the thermal conductivity of the bare Fe₃O₄ NP-based ferrofluid compared to that of the Fe₃O₄@C core-shell NP-based ferrofluid was due to the more pronounced effect of the chain-like network formation/clustering of bare Fe₃O₄ NPs in the base fluid. Finally, the experimental thermal conductivity results were compared and validated against the Maxwell effective model. These results were found to be better than results reported till date using either the same or different material systems.

Use of Super Paramagnetic Iron Oxide Nanoparticles as Drug Carriers in Brain and Ear: State of the Art and Challenges

Drug delivery and distribution in the central nervous system (CNS) and the inner ear represent a challenge for the medical and scientific world, especially because of the blood-brain and the blood-perilymph barriers. Solutions are being studied to circumvent or to facilitate drug diffusion across these structures. Using superparamagnetic iron oxide nanoparticles (SPIONs), which can be coated to change their properties and ensure biocompatibility, represents a promising tool as a drug carrier. They can act as nanocarriers and can be driven with precision by magnetic forces. The aim of this study was to systematically review the use of SPIONs in the CNS and the inner ear. A systematic PubMed search between 1999 and 2019 yielded 97 studies. In this review, we describe the applications of the SPIONS, their design, their administration, their pharmacokinetic, their toxicity and the methods used for targeted delivery of drugs into the ear and the CNS.

Nanoparticle-Mediated Drug Delivery: Blood-Brain Barrier as the Main Obstacle to Treating Infectious Diseases in CNS

BACKGROUND

Parasitic infections affecting the central nervous system (CNS) present high morbidity and mortality rates and affect millions of people worldwide. The most important parasites affecting the CNS are protozoans (Plasmodium sp., Toxoplasma gondii, Trypanosoma brucei), cestodes (Taenia solium) and free-living amoebae (Acantamoeba spp., Balamuthia mandrillaris and Naegleria fowleri). Current therapeutic regimens include the use of traditional chemicals or natural compounds that have very limited access to the CNS, despite their elevated toxicity to the host. Improvements are needed in drug administration and formulations to treat these infections and to allow the drug to cross the blood-brain barrier (BBB).

METHODS

This work aims to elucidate the recent advancements in the use of nanoparticles as nanoscaled drug delivery systems (NDDS) for treating and controlling the parasitic infections that affect the CNS, addressing not only the nature and composition of the polymer chosen, but also the mechanisms by which these nanoparticles may cross the BBB and reach the infected tissue.

RESULTS

There is a strong evidence in the literature demonstrating the potential usefulness of polymeric nanoparticles as functional carriers of drugs to the CNS. Some of them demonstrated the mechanisms by which drugloaded nanoparticles access the CNS and control the infection by using in vivo models, while others only describe the pharmacological ability of these particles to be utilized in in vitro environments.

CONCLUSION

The scarcity of the studies trying to elucidate the compatibility as well as the exact mechanisms by which NDDS might be entering the CNS infected by parasites reveals new possibilities for further exploratory projects. There is an urgent need for new investments and motivations for applying nanotechnology to control parasitic infectious diseases worldwide.

New Frontiers in Molecular Imaging with Superparamagnetic Iron Oxide Nanoparticles (SPIONs): Efficacy, Toxicity, and Future Applications

Supermagnetic Iron Oxide Nanoparticles (SPIONs) are nanoparticles that have an iron oxide core and a functionalized shell. SPIONs have recently raised much interest in the scientific community, given their exciting potential diagnostic and theragnostic applications. The possibility to modify their surface and the characteristics of their core make SPIONs a specific contrast agent for magnetic resonance imaging but also an intriguing family of tracer for nuclear medicine. An example is 68Ga-radiolabeled bombesin-conjugated to superparamagnetic nanoparticles coated with trimethyl chitosan that is selective for the gastrin-releasing peptide receptors. These receptors are expressed by several human cancer cells such as breast and prostate neoplasia. Since the coating does not interfere with the properties of the molecules bounded to the shell, it has been proposed to link SPIONs with antibodies. SPIONs can be used also to monitor the biodistribution of mesenchymal stromal cells and take place in various applications. The aim of this review of literature is to analyze the diagnostic aspect of SPIONs in magnetic resonance imaging and in nuclear medicine, with a particular focus on sentinel lymph node applications. Moreover, it is taken into account the possible toxicity and the effects on human physiology to determine the SPIONs' safety.

Therapeutic Efficiency of Multiple Applications of Magnetic Hyperthermia Technique in Glioblastoma Using Aminosilane Coated Iron Oxide Nanoparticles: In Vitro and In Vivo Study

Magnetic hyperthermia (MHT) has been shown as a promising alternative therapy for glioblastoma (GBM) treatment. This study consists of three parts: The first part evaluates the heating potential of aminosilane-coated superparamagnetic iron oxide nanoparticles (SPIONa). The second and third parts comprise the evaluation of MHT multiple applications in GBM model, either in vitro or in vivo. The obtained heating curves of SPIONa (100 nm, +20 mV) and their specific absorption rates (SAR) stablished the best therapeutic conditions for frequencies (309 kHz and 557 kHz) and magnetic field (300 Gauss), which were stablished based on three in vitro MHT application in C6 GBM cell line. The bioluminescence (BLI) signal decayed in all applications and parameters tested and 309 kHz with 300 Gauss have shown to provide the best therapeutic effect. These parameters were also established for three MHT applications in vivo, in which the decay of BLI signal correlates with reduced tumor and also with decreased tumor glucose uptake assessed by positron emission tomography (PET) images. The behavior assessment showed a slight improvement after each MHT therapy, but after three applications the motor function displayed a relevant and progressive improvement until the latest evaluation. Thus, MHT multiple applications allowed an almost total regression of the GBM tumor in vivo. However, futher evaluations after the therapy acute phase are necessary to follow the evolution or tumor total regression. BLI, positron emission tomography (PET), and spontaneous locomotion evaluation techniques were effective in longitudinally monitoring the therapeutic effects of the MHT technique.

Recent advancements in brain tumor targeting using magnetic nanoparticles

Transport of drugs through the blood-brain barrier to the brain and the toxic effects of drugs on the healthy cells can limit the effectiveness of chemotherapeutic agents. In recent years, magnetic nanoparticles (MNPs) have received much attention as targeted therapeutic and diagnostic systems due to their simplicity, ease of preparation and ability to tailor their properties such as their composition, size, surface morphology, etc. for biomedical applications. MNPs are utilized in drug delivery, radio therapeutics, hyperthermia treatment, gene therapy, biotherapeutics and diagnostic imaging. The present review will address the challenges in brain tumor targeting and discuss the application and recent developments in brain tumor targeting using MNPs.

Magnetic iron oxide nanoparticles for imaging, targeting and treatment of primary and metastatic tumors of the brain

Magnetic nanoparticles in general, and iron oxide nanoparticles in particular, have been studied extensively during the past 20 years for numerous biomedical applications. The main applications of these nanoparticles are in magnetic resonance imaging (MRI), magnetic targeting, gene and drug delivery, magnetic hyperthermia for tumor treatment, and manipulation of the immune system by macrophage polarization for cancer treatment. Recently, considerable attention has been paid to magnetic particle imaging (MPI) because of its better sensitivity compared to MRI. In recent years, MRI and MPI have been combined as a dual or multimodal imaging method to enhance the signal in the brain for the early detection and treatment of brain pathologies. Because magnetic and iron oxide nanoparticles are so diverse and can be used in multiple applications such as imaging or therapy, they have attractive features for brain delivery. However, the greatest limitations for the use of MRI/MPI for imaging and treatment are in brain delivery, with one of these limitations being the brain-blood barrier (BBB). This review addresses the current status, chemical compositions, advantages and disadvantages, toxicity and most importantly the future directions for the delivery of iron oxide based substances across the blood-brain barrier for targeting, imaging and therapy of primary and metastatic tumors of the brain.

The pH dependent surface charging and points of zero charge. VIII. Update

A critical review of the points of zero charge (PZC) obtained by potentiometric titration and of isoelectric points (IEP) obtained by electrokinetic measurements. The results from the recent literature are presented with experimental details (temperature, method, type of apparatus, etc.), and they are compared with the zero points of similar materials reported in older publications. Most studies of PZC and IEP reported in the recent papers were carried out for metal oxides and hydroxides, especially alumina, iron oxides, and titania, and the results are consistent with the PZC and IEP of similar materials reported in older literature, and summarized in previous reviews by the same author. Relatively few studies were carried out with less common materials, and IEP of (nominally) VO₂ and BN have been reported for the 1st time.

The Potential Selective Cytotoxicity of Poly (L- Lactic Acid)-Based Scaffolds Functionalized with Nanohydroxyapatite and Europium (III) Ions toward Osteosarcoma Cells

Osteosarcoma (OSA) is malignant bone tumor, occurring in children and adults, characterized by poor prognosis. Despite advances in chemotherapy and surgical techniques, the survival of osteosarcoma patients is not improving significantly. Currently, great efforts are taken to identify novel selective strategies, distinguishing between cancer and normal cells. This includes development of biomimetic scaffolds with anticancer properties that can simultaneously support and modulate proper regeneration of bone tissue. In this study cytotoxicity of scaffolds composed from poly (L-lactic acid) functionalized with nanohydroxyapatite (nHAp) and doped with europium (III) ions-10 wt % 3 mol % Eu³⁺: nHAp@PLLA was tested using human osteosarcoma cells: U-2 OS, Saos-2 and MG-63. Human adipose tissue-derived stromal cells (HuASCs) were used as non-transformed cells to determine the selective cytotoxicity of the carrier. Analysis included evaluation of cells morphology (confocal/scanning electron microscopy (SEM)), metabolic activity and apoptosis profile in cultures on the scaffolds. Results obtained indicated on high cytotoxicity of scaffolds toward all OSA cell lines, associated with a decrease of cells' viability, deterioration of metabolic activity and activation of apoptotic factors determined at mRNA and miRNA levels. Simultaneously, the biomaterials did not affect HuASCs' viability and proliferation rate. Obtained scaffolds showed a bioimaging function, due to functionalization with luminescent europium ions, and thus may find application in theranostics treatment of OSA.

Targeted magnetic separation of biomolecules and cells using earthicle-based ferrofluids

Targeting specific molecular or cell populations within single tissues or multicomponent in vitro systems is a most sought goal in biomedicine. Here we report on targeted magnetic separation of cells and biomolecules using a ferrofluid comprising superparamagnetic iron-oxide/silicate/carbon core/shell/crust nanoparticles in combination with a handheld, 2.5 cm³ NdFeB magnet (≤180 mT) and one minute exposure time. Ferrofluids were highly effective at separating (i) biomolecules, (ii) bacteria and (iii) eukaryotic cells from solutions, and they also exhibited selectivity in the separation of all three families of entities. Specifically, they were more effective at separating the negatively charged protein, albumin in the presence of the external magnetic field, but were more effective at precipitating the positively charged protein, lysozyme without the application of the external field. Because of the more effective sorption of proteins than carbohydrates on carbon and the shielding of peptidoglycans by the transmembrane proteins and hydrophilic heads of the outer membrane amphiphiles in Gram-negative bacteria, they were separated more effectively than their Gram-positive counterparts. Ferrofluids were also more efficient at separating the clinical isolate, methicillin-resistant version of S. aureus (MRSA) than its regular, lab strain and the effect is thought to be due to structural changes to the cell envelope caused by the overexpression of efflux pumps or by the higher rate of conjugation conditioning horizontal gene transfer in MRSA than in the regular, nonresistant strain. Ferrofluids also displayed a greater affinity for the cancer cells than for the normal, primary cells and allowed for targeted separation of the former after the cells were allowed to uptake the nanoparticles for 24 h. This selectivity should allow for an effective separation of cancer cells interspersed within a healthy cell population. Interaction with bacterial and eukaryotic cells was driven neither by electrostatic attraction nor chemisorption, but by weaker, van der Waals and π-interactions. Adsorption was also endothermic, irreversible for the most part, and more favorable at high concentrations, as inferred by comparison with Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms. These targeted effects are relevant for numerous fields of biomedicine and biotechnologies and require further insight for optimization and translation.

Colloids or powders: Which nanoparticle formulations do cells like more?

Understanding the difference in physicochemical properties and biological response between colloidal and powder formulations of identical materials is important before the given materials are used in a medical milieu. In this study we compared a set of biological effects of colloidal and powder formulations of composite nanoparticles comprising superparamagnetic iron oxide cores and silicate/carbon shells. Magnetic dipole interaction between adjacent nanoparticles was more pronounced in their powders than in their colloidal formulations. Nanoparticles delivered as powders were thus more responsive to the magnetic field, but exhibited reduced uptake in bone and brain cancer cells, including K7M2 osteosarcoma line and U87 and E297 glioblastoma lines. Specifically, while the alternate magnetic field elicited a more rapid heat generation in cell culture media supplemented with the magnetic powders, the nanoparticles dispersed in the same media were uptaken by the cancer cells more copiously. The cellular uptake proved to be more crucial in defining the effect on cell survival, given that suspended formulations elicited a greater degree of cancer cell death in the magnetic field compared to the powder-containing formulations. Because of this effect, colloidal formulations were able to target cancer cells more effectively than the powders: they reduced the viability of all three tested cancer cell lines to a significantly greater degree that the viability of the normal, MDCK-MDR1 cell line. It is concluded that better uptake profile can make up for the lower heating rate in the AC field and lead to a more effective magnetic hyperthermia therapy. These results also demonstrate that the direct delivery of ferrofluids is more optimal than the administration of their constitutive particles as powders.