Magnetic Drug Targeting: Preclinical in Vivo Studies, Mathematical Modeling, and Extrapolation to Humans

Development and characterization of lipid nanocapsules loaded with iron oxide nanoparticles for magnetic targeting to the blood-brain barrier

Brain drug delivery is severely hindered by the presence of the blood-brain barrier (BBB). Its functionality relies on the interactions of the brain endothelial cells with additional cellular constituents, including pericytes, astrocytes, neurons, or microglia. To boost brain drug delivery, nanomedicines have been designed to exploit distinct delivery strategies, including magnetically driven nanocarriers as a form of external physical targeting to the BBB. Herein, a lipid-based magnetic nanocarrier prepared by a low-energy method is first described. Magnetic nanocapsules with a hydrodynamic diameter of 256.7 ± 8.5 nm (polydispersity index: 0.089 ± 0.034) and a ξ-potential of -30.4 ± 0.3 mV were obtained. Transmission electron microscopy-energy dispersive X-ray spectroscopy analysis revealed efficient encapsulation of iron oxide nanoparticles within the oily core of the nanocapsules. Both thermogravimetric analysis and phenanthroline-based colorimetric assay showed that the iron oxide percentage in the final formulation was 12 wt.%, in agreement with vibrating sample magnetometry analysis, as the specific saturation magnetization of the magnetic nanocapsules was 12% that of the bare iron oxide nanoparticles. Magnetic nanocapsules were non-toxic in the range of 50-300 μg/mL over 72 h against both the human cerebral endothelial hCMEC/D3 and Human Brain Vascular Pericytes cell lines. Interestingly, higher uptake of magnetic nanocapsules in both cell types was evidenced in the presence of an external magnetic field than in the absence of it after 24 h. This increase in nanocapsules uptake was also evidenced in pericytes after only 3 h. Altogether, these results highlight the potential for magnetic targeting to the BBB of our formulation.

Tumor versus Tumor Cell Targeting in Metal-Based Nanoparticles for Cancer Theranostics

The application of metal-based nanoparticles (mNPs) in cancer therapy and diagnostics (theranostics) has been a hot research topic since the early days of nanotechnology, becoming even more relevant in recent years. However, the clinical translation of this technology has been notably poor, with one of the main reasons being a lack of understanding of the disease and conceptual errors in the design of mNPs. Strikingly, throughout the reported studies to date on in vivo experiments, the concepts of "tumor targeting" and "tumor cell targeting" are often intertwined, particularly in the context of active targeting. These misconceptions may lead to design flaws, resulting in failed theranostic strategies. In the context of mNPs, tumor targeting can be described as the process by which mNPs reach the tumor mass (as a tissue), while tumor cell targeting refers to the specific interaction of mNPs with tumor cells once they have reached the tumor tissue. In this review, we conduct a critical analysis of key challenges that must be addressed for the successful targeting of either tumor tissue or cancer cells within the tumor tissue. Additionally, we explore essential features necessary for the smart design of theranostic mNPs, where 'smart design' refers to the process involving advanced consideration of the physicochemical features of the mNPs, targeting motifs, and physiological barriers that must be overcome for successful tumor targeting and/or tumor cell targeting.

Targeted Rapamycin Delivery via Magnetic Nanoparticles to Address Stenosis in a 3D Bioprinted in Vitro Model of Pulmonary Veins

Vascular cell overgrowth and lumen size reduction in pulmonary vein stenosis (PVS) can result in elevated PV pressure, pulmonary hypertension, cardiac failure, and death. Administration of chemotherapies such as rapamycin have shown promise by inhibiting the vascular cell proliferation; yet clinical success is limited due to complications such as restenosis and off-target effects. The lack of in vitro models to recapitulate the complex pathophysiology of PVS has hindered the identification of disease mechanisms and therapies. This study integrated 3D bioprinting, functional nanoparticles, and perfusion bioreactors to develop a novel in vitro model of PVS. Bioprinted bifurcated PV constructs are seeded with endothelial cells (ECs) and perfused, demonstrating the formation of a uniform and viable endothelium. Computational modeling identified the bifurcation point at high risk of EC overgrowth. Application of an external magnetic field enabled targeting of the rapamycin-loaded superparamagnetic iron oxide nanoparticles at the bifurcation site, leading to a significant reduction in EC proliferation with no adverse side effects. These results establish a 3D bioprinted in vitro model to study PV homeostasis and diseases, offering the potential for increased throughput, tunability, and patient specificity, to test new or more effective therapies for PVS and other vascular diseases.

An Intrinsically Magnetic Epicardial Patch for Rapid Vascular Reconstruction and Drug Delivery

Myocardial infarction (MI) is a major cause of mortality worldwide. The major limitation of regenerative therapy for MI is poor cardiac retention of therapeutics, which results from an inefficient vascular network and poor targeting ability. In this study, a two-layer intrinsically magnetic epicardial patch (MagPatch) prepared by 3D printing with biocompatible materials like poly (glycerol sebacate) (PGS) is designed, poly (ε-caprolactone) (PCL), and NdFeB. The two-layer structure ensured that the MagPatch multifariously utilized the magnetic force for rapid vascular reconstruction and targeted drug delivery. MagPatch accumulates superparamagnetic iron oxide (SPION)-labelled endothelial cells, instantly forming a ready-implanted organization, and rapidly reconstructs a vascular network anastomosed with the host. In addition, the prefabricated vascular network within the MagPatch allowed for the efficient accumulation of SPION-labelled therapeutics, amplifying the therapeutic effects of cardiac repair. This study defined an extendable therapeutic platform for vascularization-based targeted drug delivery that is expected to assist in the progress of regenerative therapies in clinical applications.

Computational Assessment of Unsteady Flow Effects on Magnetic Nanoparticle Targeting Efficiency in a Magnetic Stented Carotid Bifurcation Artery

PURPOSE

Worldwide, cardiovascular disease is the leading cause of hospitalization and death. Recently, the use of magnetizable nanoparticles for medical drug delivery has received much attention for potential treatment of both cancer and cardiovascular disease. However, proper understanding of the interacting magnetic field forces and the hydrodynamics of blood flow is needed for effective implementation. This paper presents the computational results of simulated implant assisted medical drug targeting (IA-MDT) via induced magnetism intended for administering patient specific doses of therapeutic agents to specific sites in the cardiovascular system. The drug delivery scheme presented in this paper functions via placement of a faintly magnetizable stent at a diseased location in the carotid artery, followed by delivery of magnetically susceptible drug carriers guided by the local magnetic field. Using this method, the magnetic stent can apply high localized magnetic field gradients within the diseased artery, while only exposing the neighboring tissues, arteries, and organs to a modest magnetic field. The localized field gradients also produce the forces needed to attract and hold drug-containing magnetic nanoparticles at the implant site for delivering therapeutic agents to treat in-stent restenosis.

METHODS

The multi-physics computational model used in this work is from our previous work and has been slightly modified for the case scenario presented in this paper. The computational model is used to analyze pulsatile blood flow, particle motion, and particle capture efficiency in a magnetic stented region using the magnetic properties of magnetite (Fe3O4) and equations describing the magnetic forces acting on particles produced by an external cylindrical electromagnetic coil. The electromagnetic coil produces a uniform magnetic field in the computational arterial flow model domain, while both the particles and the implanted stent are paramagnetic. A Eulerian-Lagrangian technique is adopted to resolve the hemodynamic flow and the motion of particles under the influence of a range of magnetic field strengths (Br = 2T, 4T, 6T, and 8T). Particle diameter sizes of 10 nm-4 µm in diameter were evaluated. Two dimensionless numbers were evaluated in this work to characterize relative effects of Brownian motion (BM), magnetic force induced particle motion, and convective blood flow on particle motion.

RESULTS

The computational simulations demonstrate that the greatest particle capture efficiency results for particle diameters within the micron range of 0.7-4 µm, specifically in regions where flow separation and vortices are at a minimum. Similar to our previous work (which did not involve the use of a magnetic stent), it was also observed that the capture efficiency of particles decreases substantially with particle diameter, especially in the superparamagnetic regime. Contrary to our previous work, using a magnetic stent tripled the capture efficiency of superparamagnetic particles. The highest capture efficiency observed for superparamagnetic particles was 78% with an 8 T magnetic field strength and 65% with a 2 T magnetic field strength when analyzing 100 nm particles. For 10 nm particles and an 8 T magnetic field strength, the particle capture efficiency was 55% and for a 2 T magnetic field strength the particle capture efficiency was observed to be 43%. Furthermore, it was found that larger magnetic field strengths, large particle diameter sizes (1 µm and above), and slower blood flow velocity improves the particle capture efficiency. The distribution of captured particles on the vessel wall along the axial and azimuthal directions is also discussed. Results for captured particles on the vessel wall along the axial flow direction showed that the particle density decreased along the axial direction, especially after the stented region. For the entrance section of the stented region, the captured particle density distribution along the axial direction is large, corresponding to the center-symmetrical distribution of the magnetic force in that section.

CONCLUSION

The simulation results presented in this work have shown to yield favorable capture efficiencies for micron range particles and superparamagnetic particles using magnetized implants such as the stent discussed in this work. The results presented in this work justify further investigation of MDT as a treatment technique for cardiovascular disease.

Self-template synthesis of mesoporous and biodegradable Fe3O4 nanospheres as multifunctional nanoplatform for cancer therapy

Superparamagnetic Fe3O4 nanospheres have demonstrated great potential as important components in nanomedicine for cancer imaging and therapy. One of the major obstacles that impedes their application is the slow degradation of ingested Fe3O4 nanospheres, which potentially causes long-term health risks. To tackle this issue, we proposed to fabricate Fe3O4 nanospheres with mesoporous structure via a simple self-template etching method. The mesoporous Fe3O4 nanospheres not only offered large specific surface area and weak-acidic responsive degradability, but also exhibited T2-weighted magnetic resonance contrast enhancement and magnetic targeting, which made them possible to serve as excellent cancer therapeutic nanoplatform. Both inorganic photothermal therapeutic Au nanoparticles and organic chemotherapeutic doxorubicin hydrochloride were demonstrated to be successfully loaded onto such kind of nanoplatform, and the hybrid nanomedicine demonstrated synergistic photothermal and chemotherapeutic activity for tumor elimination under near infrared irradiation and improved biodegradability in weak acidic tumor microenvironment. We believe that this study paved a simple way for designing multifunctional Fe3O4-based biodegradable nanomedicine.

Machine learning assisted-nanomedicine using magnetic nanoparticles for central nervous system diseases

Magnetic nanoparticles possess unique properties distinct from other types of nanoparticles developed for biomedical applications. Their unique magnetic properties and multifunctionalities are especially beneficial for central nervous system (CNS) disease therapy and diagnostics, as well as targeted and personalized applications using image-guided therapy and theranostics. This review discusses the recent development of magnetic nanoparticles for CNS applications, including Alzheimer's disease, Parkinson's disease, epilepsy, multiple sclerosis, and drug addiction. Machine learning (ML) methods are increasingly applied towards the processing, optimization and development of nanomaterials. By using data-driven approach, ML has the potential to bridge the gap between basic research and clinical research. We review ML approaches used within the various stages of nanomedicine development, from nanoparticle synthesis and characterization to performance prediction and disease diagnosis.

Transcranial application of magnetic pulses for improving brain drug delivery efficiency via intranasal injection of magnetic nanoparticles

As the blood-brain barrier (BBB) hinders efficient drug delivery to the brain, drug delivery via the intranasal pathway, bypassing the BBB, has received considerable attention. However, intranasal administration still has anatomical and physiological limitations, necessitating further solutions to enhance effectiveness. In this study, we used transcranial magnetic stimulation (TMS) on fluorescent magnetic nanoparticles (MNPs) of different sizes (50, 100, and 300 nm) to facilitate MNP's transportation and delivery to the brain parenchyma. To validate this concept, anesthetized rats were intranasally injected with the MNPs, and TMS was applied to the center of the head. As the result, a two-fold increase in brain MNP delivery was achieved using TMS compared with passive intranasal administration. In addition, histological analysis that was performed to investigate the safety revealed no gross or microscopic damages to major organs caused by the nanoparticles. While future studies should establish the delivery conditions in humans, we expect an easy clinical translation in terms of device safety, similar to the use of conventional TMS. The strategy reported herein is the first critical step towards effective drug transportation to the brain.

Lutein-loaded chitosan/alginate-coated Fe3O4 nanoparticles as effective targeted carriers for breast cancer treatment

Magnetic drug targeting can be a strategy for effectively delivering phytochemicals in cancer treatment. Here, we demonstrate the benefit of magnetic targeting with superparamagnetic iron oxide nanoparticles for cytotoxicity enhancement of lutein (LUT) against breast cancer cells. Fabrication of LUT-loaded chitosan/alginate iron oxide nanoparticles (LUT-CS/Alg-Fe₃O₄-NPs) was optimized by a statistical approach using response surface methodology based on the Box-Behnken design. The optimized LUT-CS/Alg-Fe₃O₄-NPs with a balance among LUT concentration, copolymer coating, and iron ion concentration exhibited controlled size, narrow size distribution, better crystallinity, excellent saturation magnetization, and sustained-release profile. The negligible magnetic coercivity and remanent magnetization confirmed the superparamagnetism of the prepared NPs. The optimized LUT-CS/Alg-Fe₃O₄-NPs were biocompatible while exhibiting a significantly enhanced cytotoxicity towards breast cancer MCF-7 cells upon exposure to a permanent magnet compared to free LUT with a 4-fold increase, suggesting the potential of LUT-CS/Alg-Fe₃O₄-NPs as magnetically targeted delivery for breast cancer.

Theranostics Nanomedicine Applications for Colorectal Cancer and Metastasis: Recent Advances

Colorectal cancer (CRC) is the third most common cancer worldwide, and metastatic CRC is a fatal disease. The CRC-affected tissues show several molecular markers that could be used as a fresh strategy to create newer methods of treating the condition. The liver and the peritoneum are where metastasis occurs most frequently. Once the tumor has metastasized to the liver, peritoneal carcinomatosis is frequently regarded as the disease's final stage. However, nearly 50% of CRC patients with peritoneal carcinomatosis do not have liver metastases. New diagnostic and therapeutic approaches must be developed due to the disease's poor response to present treatment choices in advanced stages and the necessity of an accurate diagnosis in the early stages. Many unique and amazing nanomaterials with promise for both diagnosis and treatment may be found in nanotechnology. Numerous nanomaterials and nanoformulations, including carbon nanotubes, dendrimers, liposomes, silica nanoparticles, gold nanoparticles, metal-organic frameworks, core-shell polymeric nano-formulations, and nano-emulsion systems, among others, can be used for targeted anticancer drug delivery and diagnostic purposes in CRC. Theranostic approaches combined with nanomedicine have been proposed as a revolutionary approach to improve CRC detection and treatment. This review highlights recent studies, potential, and challenges for the development of nanoplatforms for the detection and treatment of CRC.

Synergistic Effect of Magneto-Mechanical Bioengineered Stem Cells and Magnetic Field to Alleviate Osteoporosis

Therapeutic bioengineering based on stem cell therapy holds great promise in biomedical applications. However, the application of this treatment is limited in orthopedics because of their poor survival, weak localization, and low cell retention. In this work, magneto-mechanical bioengineered cells consisting of magnetic silica nanoparticles (MSNPs) and mesenchymal stem cells (MSCs) are prepared to alleviate osteoporosis. The magneto-mechanical bioengineered MSCs with spatial localization, cell retention, and directional tracking capabilities could be mediated by a guided magnetic field (MF) in vitro and in vivo. Furthermore, high uptake rates of the MSNPs ensure the efficient construction of magnetically controlled MSCs within 2 h. In conjunction with external MF, the magneto-mechanical bioengineered MSCs have the potential for the activation of the YAP/β-catenin signaling pathway, which could further promote osteogenesis, mineralization, and angiogenesis. The synergistic effects of MSNPs and guided MF could also decline bone resorption to rebalance bone metabolism in bone loss diseases. In vivo experiments confirm that the functional MSCs and guided MF could effectively alleviate postmenopausal osteoporosis, and the bone mass of the treated osteoporotic bones by using the bioengineered cells for 6 weeks is nearly identical to that of the healthy ones. Our results provide a new avenue for osteoporosis management and treatment, which contribute to the future advancement of magneto-mechanical bioengineering and treatment.

A Magnetically Driven Amoeba-Like Nanorobot for Whole-Process Active Drug Transport

The passive diffusion performance of nanocarriers results in inefficient drug transport across multiple biological barriers and consequently cancer therapy failure. Here, a magnetically driven amoeba-like nanorobot (amNR) is presented for whole-process active drug transport. The amNR is actively extravasated from blood vessels and penetrated into deep tumor tissue through a magnetically driven deformation effect. Moreover, the acidic microenvironment of deep tumor tissue uncovers the masked targeting ligand of amNR to achieve active tumor cell uptake. Furthermore, the amNR rapidly releases the encapsulated doxorubicin (DOX) after alternating magnetic field application. The amNRs eventually deliver DOX into ≈92.3% of tumor cells and completely delay tumor growth with an inhibition rate of 96.1%. The deformable amNRs, with the assistance of magnetic field application, provide a facile strategy for whole-process active drug transport.

Fe3O4 Composite Superparticles with RGD/Magnetic Dual-Targeting Capabilities for the Imaging and Treatment of Non-Small Cell Lung Cancer

In clinical practice, the incidence and mortality of non-small cell lung cancer are increasing year by year, which is a serious threat to the health of patients. Once the optimal surgical window is missed, the toxic side effects of chemotherapy have to be confronted. With the rapid development of nanotechnology in recent years, medical science and health have been greatly impacted. Therefore, in this manuscript, we design and prepare chemotherapeutic drug vinorelbine (VRL)-loaded polydopamine (PDA) shell-coated Fe₃O₄ superparticles, and further graft the targeted ligand RGD onto their surface. Because of the introduction of the PDA shell, the toxicity of the prepared Fe₃O₄@PDA/VRL-RGD SPs is greatly reduced. At the same time, due to the existence of Fe₃O₄, the Fe₃O₄@PDA/VRL-RGD SPs also have MRI contrast capability. Under the dual-targeting effect of RGD peptide and external magnetic field, Fe₃O₄@PDA/VRL-RGD SPs can accumulate into tumors effectively. The accumulated superparticles in the tumor sites can not only effectively identify and mark the location and boundary of the tumor under MRI, guideing the application of near-infrared laser, but also release the loaded VRL under the stimulation of the acidic microenvironment of the tumor to play the role of chemotherapy. On further combination with photothermal therapy under laser irradiation, A549 tumors are completely eliminated without recurrence. Our proposed RGD/magnetic field dual-targeting strategy can effectively improve the bioavailability of nanomaterials and contribute to better imaging and therapeutic effects, which has a promising application prospect in the future.

The role of tumor model in magnetic targeting of magnetosomes and ultramagnetic liposomes

The combined passive and active targeting of tumoral tissue remains an active and relevant cancer research field. Here, we exploit the properties of two highly magnetic nanomaterials, magnetosomes and ultramagnetic liposomes, in order to magnetically target prostate adenocarcinoma tumors, implanted orthotopically or subcutaneously, to take into account the role of tumor vascularization in the targeting efficiency. Analysis of organ biodistribution in vivo revealed that, for all conditions, both nanomaterials accumulate mostly in the liver and spleen, with an overall low tumor retention. However, both nanomaterials were more readily identified in orthotopic tumors, reflecting their higher tumor vascularization. Additionally, a 2- and 3-fold increase in nanomaterial accumulation was achieved with magnetic targeting. In summary, ultramagnetic nanomaterials show promise mostly in the targeting of highly-vascularized orthotopic murine tumor models.

Computational Assessment of Magnetic Nanoparticle Targeting Efficiency in a Simplified Circle of Willis Arterial Model

This paper presents the methodology and computational results of simulated medical drug targeting (MDT) via induced magnetism intended for administering intravenous patient-specific doses of therapeutic agents in a Circle of Willis (CoW) model. The multi-physics computational model used in this work is from our previous works. The computational model is used to analyze pulsatile blood flow, particle motion, and particle capture efficiency in a magnetized region using the magnetic properties of magnetite (Fe₃O₄) and equations describing the magnetic forces acting on particles produced by an external cylindrical electromagnetic coil. A Eulerian-Lagrangian technique is implemented to resolve the hemodynamic flow and the motion of particles under the influence of a range of magnetic field strengths (B_r = 2T, 4T, 6T, and 8T). Particle diameter sizes of 10 nm to 4 µm in diameter were assessed. Two dimensionless numbers are also investigated a priori in this study to characterize relative effects of Brownian motion (BM), magnetic force-induced particle motion, and convective blood flow on particle motion. Similar to our previous works, the computational simulations demonstrate that the greatest particle capture efficiency results for particle diameters within the micron range, specifically in regions where flow separation and vortices are at a minimum. Additionally, it was observed that the capture efficiency of particles decreases substantially with smaller particle diameters, especially in the superparamagnetic regime. The highest capture efficiency observed for superparamagnetic particles was 99% with an 8T magnetic field strength and 95% with a 2T magnetic field strength when analyzing 100 nm particles. For 10 nm particles and an 8T magnetic field strength, the particle capture efficiency was 48%, and for a 2T magnetic field strength the particle capture efficiency was 33%. Furthermore, it was found that larger magnetic field strengths, large particle diameter sizes (1 µm and above), and slower blood flow velocity increase the particle capture efficiency. The key finding in this work is that favorable capture efficiencies for superparamagnetic particles were observed in the CoW model for weak fields (B_r < 4T) which demonstrates MDT as a possible viable treatment candidate for cardiovascular disease.

Influence of PEG Chain Length of Functionalized Magnetic Nanoparticles on the Cytocompatibility and Immune Competence of Primary Murine Macrophages and Dendritic Cells

A major drawback of nanoparticles (NPs) for biomedical applications is their preferential phagocytosis in immune cells, which can be avoided by surface modifications like PEGylation. Nevertheless, examinations of different polyethylene glycol (PEG) chain lengths on the competence of immune cells as well as possible immunotoxic effects are still sparse. Therefore, primary murine macrophages and dendritic cells were generated and incubated with magnetic nanoporous silica nanoparticles (MNPSNPs) modified with different mPEG chains (2 kDa, 5 kDa, and 10 kDa). Cytotoxicity, cytokine release, and the formation of reactive oxygen species (ROS) were determined. Immune competence of both cell types was examined and uptake of MNPSNPs into macrophages was visualized. Concentrations up to 150 µg/mL MNPSNPs showed no effects on the metabolic activity or immune competence of both cell types. However, ROS significantly increased in macrophages incubated with larger PEG chains, while the concentration of cytokines (TNF-α and IL-6) did not indicate a proinflammatory process. Investigations on the uptake of MNPSNPs revealed no differences in the onset of internalization and the intensity of intracellular fluorescence. The study gives no indication for an immunotoxic effect of PEGylated MNPSNPs. Nevertheless, there is still a need for optimization regarding their internalization to ensure an efficient drug delivery.

Enhanced Tumor Accumulation of Multimodal Magneto-Plasmonic Nanoparticles via an Implanted Micromagnet-Assisted Delivery Strategy

One of the major shortcomings of nano carriers-assisted cancer therapeutic strategies continues to be the inadequate tumor penetration and retention of systemically administered nanoformulations and its off-target toxicity. Stromal parameters-related heterogeneity in enhanced permeability and retention effect and physicochemical properties of the nanoformulations immensely contributes to their poor tumor extravasation. Herein, a novel tumor targeting strategy, where an intratumorally implanted micromagnet can significantly enhance accumulation of magneto-plasmonic nanoparticles (NPs) at the micromagnet-implanted tumor in bilateral colorectal tumor models while limiting their off-target accumulation, is demonstrated. To this end, novel multimodal gold/iron oxide NPs comprised of an array of multifunctional moieties with high therapeutic, sensing, and imaging potential are developed. It is also discovered that cancer cell targeted NPs in combination with static magnetic field can selectively induce cancer cell death. A multimodal caspase-3 nanosensor is also developed for real-time visualization of selective induction of apoptosis in cancer cells. In addition, the photothermal killing capability of these NPs in vitro is evaluated, and their potential for enhanced photothermal ablation in tissue samples is demonstrated. Building on current uses of implantable devices for therapeutic purposes, this study envisions the proposed micromagnet-assisted NPs delivery approach may be used to accelerate the clinical translation of various nanoformulations.

Fabrication of Curcumin Diethyl γ-Aminobutyrate-Loaded Chitosan-Coated Magnetic Nanocarriers for Improvement of Cytotoxicity against Breast Cancer Cells

This study shows the effectiveness of magnetic-guide targeting in the delivery of curcumin diethyl γ-aminobutyrate (CUR-2GE), a prodrug of curcumin (CUR) previously synthesized to overcome unfavorable physicochemical properties of CUR. In this study, chitosan (Ch)-coated iron oxide nanoparticles (Ch-IONPs) were fabricated and optimized using Box-Behnken design-based response surface methodology for delivery of CUR-2GE. Ch was used as a coating material on the nanoparticle surface to avoid aggregation. The optimized condition for preparing Ch-IONPs consisted of using 4 mg Ch fabricated at pH 11 under a reaction temperature of 85 °C. The optimized Ch-IONPs were successfully loaded with CUR-2GE with sufficient loading capacity (1.72 ± 0.01%) and encapsulation efficiency (94.9 ± 0.8%). The obtained CUR-2GE-loaded Ch-IONPs (CUR-2GE-Ch-IONPs) exhibited desirable characteristics including a particle size of less than 50 nm based on TEM images, superparamagnetic property, highly crystalline IONP core, sufficient stability, and sustained-release profile. In the presence of permanent magnets, CUR-2GE-Ch-IONPs significantly increased cellular uptake and cytotoxicity toward MDA-MB-231 with a 12-fold increase in potency compared to free CUR-2GE, indicating the potential of magnetic-field assisted delivery of CUR-2GE-Ch-IONPs for the treatment of triple-negative breast cancer.

Nanotechnology for colorectal cancer detection and treatment

Colorectal cancer (CRC) is the third most diagnosed cancer and the second leading cause of cancer-related mortality in the United States. Across the globe, people in the age group older than 50 are at a higher risk of CRC. Genetic and environmental risk factors play a significant role in the development of CRC. If detected early, CRC is preventable and treatable. Currently, available screening methods and therapies for CRC treatment reduce the incidence rate among the population, but the micrometastasis of cancer may lead to recurrence. Therefore, the challenge is to develop an alternative therapy to overcome this complication. Nanotechnology plays a vital role in cancer treatment and offers targeted chemotherapies directly and selectively to cancer cells, with enhanced therapeutic efficacy. Additionally, nanotechnology elevates the chances of patient survival in comparison to traditional chemotherapies. The potential of nanoparticles includes that they may be used simultaneously for diagnosis and treatment. These exciting properties of nanoparticles have enticed researchers worldwide to unveil their use in early CRC detection and as effective treatment. This review discusses contemporary methods of CRC screening and therapies for CRC treatment, while the primary focus is on the theranostic approach of nanotechnology in CRC treatment and its prospects. In addition, this review aims to provide knowledge on the advancement of nanotechnology in CRC and as a starting point for researchers to think about new therapeutic approaches using nanotechnology.

Magnetic Iron Nanoparticles: Synthesis, Surface Enhancements, and Biological Challenges

This review focuses on the role of magnetic nanoparticles (MNPs), their physicochemical properties, their potential applications, and their association with the consequent toxicological effects in complex biologic systems. These MNPs have generated an accelerated development and research movement in the last two decades. They are solving a large portion of problems in several industries, including cosmetics, pharmaceuticals, diagnostics, water remediation, photoelectronics, and information storage, to name a few. As a result, more MNPs are put into contact with biological organisms, including humans, via interacting with their cellular structures. This situation will require a deeper understanding of these particles’ full impact in interacting with complex biological systems, and even though extensive studies have been carried out on different biological systems discussing toxicology aspects of MNP systems used in biomedical applications, they give mixed and inconclusive results. Chemical agencies, such as the Registration, Evaluation, Authorization, and Restriction of Chemical substances (REACH) legislation for registration, evaluation, and authorization of substances and materials from the European Chemical Agency (ECHA), have held meetings to discuss the issue. However, nanomaterials (NMs) are being categorized by composition alone, ignoring the physicochemical properties and possible risks that their size, stability, crystallinity, and morphology could bring to health. Although several initiatives are being discussed around the world for the correct management and disposal of these materials, thanks to the extensive work of researchers everywhere addressing the issue of related biological impacts and concerns, and a new nanoethics and nanosafety branch to help clarify and bring together information about the impact of nanoparticles, more questions than answers have arisen regarding the behavior of MNPs with a wide range of effects in the same tissue. The generation of a consolidative framework of these biological behaviors is necessary to allow future applications to be manageable.

Efficient Magneto-Luminescent Nanosystems based on Rhodamine-Loaded Magnetite Nanoparticles with Optimized Heating Power and Ideal Thermosensitive Fluorescence

Nanosystems that simultaneously contain fluorescent and magnetic modules can offer decisive advantages in the development of new biomedical approaches. A biomaterial that enables multimodal imaging and contains highly efficient nanoheaters together with an intrinsic temperature sensor would become an archetypical theranostic agent. In this work, we have designed a magneto-luminescent system based on Fe3O4 NPs with large heating power and thermosensitive rhodamine (Rh) fluorophores that exhibits the ability to self-monitor the hyperthermia degree. Three samples composed of highly homogeneous Fe3O4 NPs of ∼25 nm and different morphologies (cuboctahedrons, octahedrons, and irregular truncated-octahedrons) have been finely synthesized. These NPs have been thoroughly studied in order to choose the most efficient inorganic core for magnetic hyperthermia under clinically safe radiofrequency. Surface functionalization of selected Fe3O4 NPs has been carried out using fluorescent copolymers composed of PMAO, PEG and Rh. Copolymers with distinct PEG tail lengths (5-20 kDa) and different Rh percentages (5, 10, and 25%) have been synthesized, finding out that the copolymer with 20 kDa PEG and 10% Rh provides the best coating for an efficient fluorescence with minimal aggregation effects. The optimized Fe3O4@Rh system offers very suitable fluorescence thermosensitivity in the therapeutic hyperthermia range. Additionally, this sample presents good biocompatibility and displays an excellent heating capacity within the clinical safety limits of the AC field (≈ 1000 W/g at 142 kHz and 44 mT), which has been confirmed by both calorimetry and AC magnetometry. Thus, the current work opens up promising avenues toward next-generation medical technologies.

Magnetic Forces by Permanent Magnets to Manipulate Magnetoresponsive Particles in Drug-Targeting Applications

This study presents preliminary computational and experimental findings on two alternative permanent magnet configurations helpful for magnetic drug administration in vivo. A numerical simulation and a direct experimental measurement of the magnetic induction on the magnet system's surface were used to map the magnetic field. In addition, the ferrite-type (grade Y35) and permanent neodymium magnets (grade N52) to produce powerful magnetic forces were also examined analytically and quantitatively. Ansys-Maxwell software and Finite Element Method Magnetism (FEMM) version 4.2 were used for all numerical computations in the current investigation. For both magnets, the generated magnetic fields were comparatively studied for targeting Fe particles having a diameter of 6 μm. The following findings were drawn from the present investigation: (i) the particle deposition on the vessel wall is greatly influenced by the intensity of the magnetic field, the magnet type, the magnet size, and the magnetic characteristics of the micro-sized magnetic particles (MSMPs); (ii) ferrite-type magnets might be employed to deliver magnetoresponsive particles to a target location, even if they are less powerful than neodymium magnets; and (iii) the results from the Computational Fluid Dynamics( CFD) models agree well with the measured magnetic field induction, magnetic field strength, and their fluctuation with the distance from the magnet surface.

Iron oxide nanoparticle targeting mechanism and its application in tumor magnetic resonance imaging and therapy

Iron oxide nanoparticles (IONPs) can be applied to targeted drug delivery, targeted diagnosis and treatment of tumors due to their easy preparation, good biocompatibility, low biotoxicity, high imaging quality, high magnetothermal sensitivity and stable targeting after certain surface modifications. However, the complexity of the mechanism of action and their properties has led to there being few clinical applications of IONPs. This review first describes the targeting mechanisms of IONPs and their toxicity issues, then discusses the applications of IONP targeting studies in tumor MRI. Finally, the applications of IONP targeting in tumor therapy are listed. The authors show the advantages of targeting IONPs and hope that the review will increase the possibility of converting IONPs from biomedical applications to clinical applications.

Micro/Nanosystems for Magnetic Targeted Delivery of Bioagents

Targeted delivery of pharmaceuticals is promising for efficient disease treatment and reduction in adverse effects. Nano or microstructured magnetic materials with strong magnetic momentum can be noninvasively controlled via magnetic forces within living beings. These magnetic carriers open perspectives in controlling the delivery of different types of bioagents in humans, including small molecules, nucleic acids, and cells. In the present review, we describe different types of magnetic carriers that can serve as drug delivery platforms, and we show different ways to apply them to magnetic targeted delivery of bioagents. We discuss the magnetic guidance of nano/microsystems or labeled cells upon injection into the systemic circulation or in the tissue; we then highlight emergent applications in tissue engineering, and finally, we show how magnetic targeting can integrate with imaging technologies that serve to assist drug delivery.

Synthesis and Characterization of Magnetic Composite Theragnostics by Nano Spray Drying

Composites of magnetite nanoparticles encapsulated with polymers attract interest for many applications, especially as theragnostic agents for magnetic hyperthermia, drug delivery, and magnetic resonance imaging. In this work, magnetite nanoparticles were synthesized by coprecipitation and encapsulated with different polymers (Eudragit S100, Pluronic F68, Maltodextrin, and surfactants) by nano spray drying technique, which can produce powders of nanoparticles from solutions or suspensions. Transmission and scanning electron microscopy images showed that the bare magnetite nanoparticles have 10.5 nm, and after encapsulation, the particles have approximately 1 μm, with size and shape depending on the material’s composition. The values of magnetic saturation by SQUID magnetometry and mass residues by thermogravimetric analysis were used to characterize the magnetic content in the materials, related to their magnetite/polymer ratios. Zero-field-cooling and field-cooling (ZFC/FC) measurements showed how blocking temperatures of the powders of the composites are lower than that of bare magnetite, possibly due to lower magnetic coupling, being an interesting system to study magnetic interactions of nanoparticles. Furthermore, studies of cytotoxic effect, hydrodynamic size, and heating capacity for hyperthermia (according to the application of an alternate magnetic field) show that these composites could be applied as a theragnostic material for a non-invasive administration such as nasal.

Iron Oxide Nanoparticles: Physicochemical Characteristics and Historical Developments to Commercialization for Potential Technological Applications

Iron oxide nanoparticles (IONPs) have gained increasing attention in various biomedical and industrial sectors due to their physicochemical and magnetic properties. In the biomedical field, IONPs are being developed for enzyme/protein immobilization, magnetofection, cell labeling, DNA detection, and tissue engineering. However, in some established areas, such as magnetic resonance imaging (MRI), magnetic drug targeting (MDT), magnetic fluid hyperthermia (MFH), immunomagnetic separation (IMS), and magnetic particle imaging (MPI), IONPs have crossed from the research bench, received clinical approval, and have been commercialized. Additionally, in industrial sectors IONP-based fluids (ferrofluids) have been marketed in electronic and mechanical devices for some time. This review explores the historical evolution of IONPs to their current state in biomedical and industrial applications.

Nano-engineered immune cells as "guided missiles" for cancer therapy

Immune cells can actively regulate tumors or inflammatory sites and have good biocompatibility and safety. Currently, they are one of the most promising candidates for drug delivery systems. Moreover, immune cells can significantly extend the circulation time of nanoparticles and have broad-spectrum tumor-targeting properties. This article first introduces the immune cell types most commonly used in recent years, analyzes their advantages and disadvantages, and elucidates their application in anti-tumor therapy. Next, the various ways of loading nanoparticles on immune cells that have been used in recent years are summarized and simply divided into two categories: backpacks and Trojan horses. Finally, the two "mountains" that stand in front of us when using immune cells as cell carriers, off-target problems and effective release strategies, are discussed.

Aspects of high-performance and bio-acceptable magnetic nanoparticles for biomedical application

This review covers extensively the synthesis & surface modification, characterization, and application of magnetic nanoparticles. For biomedical applications, consideration should be given to factors such as design strategies, the synthesis process, coating, and surface passivation. The synthesis method regulates post-synthetic change and specific applications in vitro and in vivo imaging/diagnosis and pharmacotherapy/administration. Special insights have been provided on biodistribution, pharmacokinetics, and toxicity in a living system, which is imperative for their wider application in biology. These nanoparticles can be decorated with multiple contrast agents and thus can also be used as a probe for multi-mode imaging or double/triple imaging, for example, MRI-CT, MRI-PET. Similarly loading with different drug molecules/dye/fluorescent molecules and integration with other carriers have found application not only in locating these particles in vivo but simultaneously target drug delivery/hyperthermia inside the body. Studies are underway to collect the potential of these magnetically driven nanoparticles in various scientific fields such as particle interaction, heat conduction, imaging, and magnetism. Surely, this comprehensive data will help in the further development of advanced techniques for theranostics based on high-performance magnetic nanoparticles and will lead this research area in a new sustainable direction.

One-Step and Facile Synthesis of Poly(phenylalanine) as a Robust Drug Carrier for Enhanced Cancer Therapy

In recent decades, many poly(amino acid)s have been successfully prepared for various biomedical applications. To date, the synthesis and purification procedures used to generate these poly(amino acid)s have generally been complicated and costly. Here, a one-step synthesis strategy was developed and optimized via direct polymerization using thionyl chloride to easily and economically obtain poly(amino acid)s. Phenylalanine (Phe) was selected as a model amino acid to construct a family of biodegradable and biocompatible poly(phenylalanine) (PPhe) molecules with a tunable molecular weight. The prepared PPhe can self-assemble into nanoparticles (PP-NPs) through nanoprecipitation with a particle size of approximately 100 nm. PP-NPs exhibit a high drug-loading capacity (>12 wt %) of paclitaxel (PTX, a commercial antitumor drug) and good therapeutic effects in CT26 cells. The in vivo evaluation of PTX@PP-NPs indicates that it has a prolonged blood circulation time and high tumor aggregation after intravenous injection, resulting in significant antitumor effects in CT26 tumor-bearing mice with minimal toxicity to normal organs. Overall, this study provides a facile and simple strategy for synthesizing poly(amino acids) and a PPhe-based nanoparticle platform for effectively delivering various small-molecule drugs.

FEM based simulation of magnetic drug targeting in a multibranched vessel model

BACKGROUND AND OBJECTIVE

Magnetic drug targeting (MDT) is a promising technology to improve cancer therapy. MDT describes the accumulation of drug loaded superparamagnetic iron oxide nanoparticles (SPIONs) at a desired location, e. g. a tumor, by application of a magnetic field. Here, we evaluate the effectivity of MDT for an endoscopic placement of two different configurations of magnet arrays, i. e. six magnets with same poles facing each other and a Halbach array. Compared to conventional magnet setups outside the body, this endoscopic placement gives the possibility to achieve higher magnetic field gradients inside the tumor.

METHODS

For such a MDT concept, we present FEM based simulations of MDT tracing single SPIONs in a 3D geometry of eight multibranched vessels with sizes in the range of capillaries. In these simulations, the effect of the magnetic field gradient as well as of magnet distance to the vessel geometry, magnetic flux density of the magnets, SPIONs hydrodynamic diameter and magnetic moment on the MDT effectivity is calculated. The blood flow is modelled as an incompressible Newtonian fluid and the SPIONs are suspended in the blood flow. Statistical significance of the targeting effectivity results is tested with the Mann-Whitney-U-Test.

RESULTS

The results show that the magnetic targeting effectivity is up to 32 % higher than the one calculated without the presence of a magnetic field. In the investigated vessel network, this effect on the targeting effectivity is dependent on the number of local magnetic field maxima that are approached with a high gradient and is noticeable up to 200 µm distance of the magnet to the vessel geometry.

CONCLUSIONS

We conclude that for an effective application of MDT, the magnet configuration needs to be placed close to the tumor and should yield a large number of magnetic field maxima that are approached with a high gradient.

Magnetic implants in vivo guiding sorafenib liver delivery by superparamagnetic solid lipid nanoparticles

HYPOTHESIS

Solid lipid nanoparticles (SLNs), co-encapsulating superparamagnetic iron oxide nanoparticles and sorafenib, have been exploited for magnetic-guided drug delivery to the liver. Two different magnetic configurations, both comprising two small magnets, were under-skin implanted to investigate the effect of the magnetic field topology on the magnetic SLNP accumulation in liver tissues. A preliminary simulation analysis was performed to predict the magnetic field topography for each tested configuration.

EXPERIMENTS

SLNs were prepared using a hot homogenization approach and characterized using complementary techniques. Their in vitro biological behavior was assessed in HepG-2 liver cancer cells; wild-type mice were used for the in vivo study. The magnet configuration that resulted in a higher magnetic targeting efficiency was investigated by evaluating the iron content in homogenated murine liver tissues.

FINDINGS

SLNs, characterized by an average size smaller than 200 nm, retained their superparamagnetic behavior and relevant molecular resonance imaging properties as negative contrast agents. The evaluation of iron accumulation in the liver tissues was consistent with the magnetic induction profile of each magnet configuration, concurring with the results predicted by simulation analysis and obtained by measurements in living mice.

Model-based optimized steering and focusing of local magnetic particle concentrations for targeted drug delivery

Magnetic drug targeting (MDT) is an application in the field of targeted drug delivery in which magnetic (nano)particles act as drug carriers. The particles can be steered toward specific regions in the human body by adapting the currents of external (electro)magnets. Accurate models of particle movement and control algorithms for the electromagnet currents are two of the many requirements to ensure effective drug targeting. In this work, a control approach for the currents is presented, based on an underlying physical model that describes the dynamics of particles in a liquid in terms of their concentration in each point in space. Using this model, the control algorithm determines the currents generating the magnetic fields that maximize the particle concentration in spots of interest over a period of time. Such an approach is computationally only feasible thanks to our innovative combination of model order reduction with the method of direct multiple shooting. Simulation results of an in-vitro targeting setup demonstrated that a particle collection can be successfully guided toward the targeted spot with limited dispersion through a surrounding liquid. As now present and future particle behavior can be taken into account, and non-stationary surrounding liquids can be dealt with, a more precise and flexible targeting is achieved compared to existing MDT methods. This proves that the presented methodology can bring MDT closer to its clinical application. Moreover, the developed model is compatible with state-of-the-art imaging methods, paving the way for theranostic platforms that combine both therapy as well as diagnostics.

Nanotherapeutic approaches to target mitochondria in cancer

Treatment of cancer cells exemplifies a difficult test in the light of challenges associated with the nature of cancer cells and the severe side effects too. After making a large number of trials using both traditional and advanced therapies (immunotherapy and hormone therapy), approaches to design new therapies have reached a saturation level. However, nanotechnology-based approaches exhibit higher efficacy and great potential to bypass many of such therapeutic limitations. Because of their higher target specificity, the use of nanoparticles offers incredible potential in cancer therapeutics. Mitochondria, acting as a factory of energy production in cells, reveal an important role in the death as well as the survival of cells. Because of its significant involvement in the proliferation of cancer cells, it is being regarded as an important target for cancer therapeutics. Numerous studies reveal that nanotechnology-based approaches to directly target the mitochondria may help in improving the survival rate of cancer patients. In the current study, we have detailed the significance of mitochondria in the development of cancer phenotype, as well as indicated it as the potential targets for cancer therapy. Our study further highlights the importance of different nanoparticle-based approaches to target mitochondria of cancer cells and the associated outcomes of different studies. Though, nanotechnology-based approaches to target mitochondria of cancer cells demonstrate a potential and efficient way in cancer therapeutics. Yet, further study is needed to overcome the linked limitations.

Magnetic Nanoparticles in Biology and Medicine: Past, Present, and Future Trends

The use of magnetism in medicine has changed dramatically since its first application by the ancient Greeks in 624 BC. Now, by leveraging magnetic nanoparticles, investigators have developed a range of modern applications that use external magnetic fields to manipulate biological systems. Drug delivery systems that incorporate these particles can target therapeutics to specific tissues without the need for biological or chemical cues. Once precisely located within an organism, magnetic nanoparticles can be heated by oscillating magnetic fields, which results in localized inductive heating that can be used for thermal ablation or more subtle cellular manipulation. Biological imaging can also be improved using magnetic nanoparticles as contrast agents; several types of iron oxide nanoparticles are US Food and Drug Administration (FDA)-approved for use in magnetic resonance imaging (MRI) as contrast agents that can improve image resolution and information content. New imaging modalities, such as magnetic particle imaging (MPI), directly detect magnetic nanoparticles within organisms, allowing for background-free imaging of magnetic particle transport and collection. "Lab-on-a-chip" technology benefits from the increased control that magnetic nanoparticles provide over separation, leading to improved cellular separation. Magnetic separation is also becoming important in next-generation immunoassays, in which particles are used to both increase sensitivity and enable multiple analyte detection. More recently, the ability to manipulate material motion with external fields has been applied in magnetically actuated soft robotics that are designed for biomedical interventions. In this review article, the origins of these various areas are introduced, followed by a discussion of current clinical applications, as well as emerging trends in the study and application of these materials.

Anti-microbial and anti-cancer activities of Mn0.5Zn0.5DyxFe2-xO4 (x ≤ 0.1) nanoparticles

Combining two or more nanoparticles is a promising approach. Previously we have reported synthesis of nanoparticles Dysprosium (Dy) substituted with manganese (Mn) zinc (Zn) by using ultrasonication method. The five different nanoparticles (NPs) Mn_0.5Zn_0.5Dy_xFe_2-xO₄ (x ≤ 0.1) have been structurally and morphologically characterized but there is no report on the biological application of these NPs. In the present study, we have examined the anti-cancer, anti-bacterial, and anti-fungal activities of Mn_0.5Zn_0.5Dy_xFe_2-xO₄ (x ≤ 0.1) NPs. Human colorectal carcinoma cells (HCT-116) were tested with different concentrations of NPs by using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. In addition, the impact of NPs was also examined on normal cells such as human embryonic kidney cells, HEK-293. After 48 h of treatment, Mn_0.5Zn_0.5Dy_xFe_2-xO₄ NPs (x = 0.02, 0.04 and 0.06) showed no inhibitory action on cancer cell's growth and proliferation, whereas Mn_0.5Zn_0.5Dy_xFe_2-xO₄ NPs (x = 0.08 and 0.1) showed profound inhibitory action on cancer cell's growth and proliferation. However, the treatment of Mn_0.5Zn_0.5Dy_xFe_2-xO₄ NPs on the normal cells (HEK-293) did not show cytotoxic or inhibitory action on HEK-293 cells. The treatment of Mn_0.5Zn_0.5Dy_xFe_2-xO₄ NPs (x ≤ 0.1) also inhibited both the bacteria (Escherichia coli ATCC35218 and Staphylococcus aureus) with lowest MIC and MBC values of 4 and 8 mg/mL and fungus (Candida albicans) with MIC and MFC values of 4 and 8 mg/mL on treatment with x = 0.08 and 0. 1.

Targeted Drug Delivery: Trends and Perspectives

BACKGROUND

Due to various limitations in conventional drug delivery system, it is important to focus on the target-specific drug delivery system where we can deliver the drug without any degradation. Among various challenges faced by a formulation scientist, delivering the drug to its right site, in its right dose, is also an important aim. A focused drug transport aims to extend, localize, target and have a safe drug interaction with the diseased tissue.

OBJECTIVE

The aim of targeted drug delivery is to make the required amount of the drug available at its desired site of action. Drug targeting can be accomplished in a number ways that include enzyme mediation, pH-dependent release, use of special vehicles, receptor targeting among other mechanisms. Intelligently designed targeted drug delivery systems also offer the advantages of a low dose of the drug along with reduced side effects which ultimately improves patient compliance. Incidences of dose dumping and dosage form failure are negligible. A focused drug transport aims to have a safe drug interaction with the diseased tissue.

CONCLUSION

This review focuses on the available targeting techniques for delivery to the colon, brain and other sites of interest. Overall, the article should make an excellent read for the researchers in this area. Newer drug targets may be identified and exploited for successful drug targeting.

Fenton-magnetic based therapy by dual-chemodrug-loaded magnetic hydroxyapatite against colon cancer

Fenton-based therapy is emerging as an effective and selective strategy against cancer. However, a low concentration of transition metal ions, insufficient endogenous H₂O_2, and a high level of antioxidant activity within the cancer cells have hindered the therapeutic efficacy of this strategy. To address these issues, in this study, the Fenton reagent (magnetic hydroxyapatite, mHAP) was accompanied with chemotherapy drugs (cisplatin (CDDP) and methotrexate (MTX)) and static magnetic field (SMF), in such a way to be a pH-, redox-, and magnetic-responsive nanoplatform. In vitro and in vivo experiments revealed higher toxicity of the final construct, MTX.CDDP@mHAP, toward colon cancer cells, as compared with that of free drugs. The most effective antitumor activity was observed as MTX.CDDP@mHAP-treated tumor cells were exposed to SMF (0.9 T) and no noticeable damage was observed in the normal cells and tissues. Active targeting by MTX and magnetic targeting by mHAP under magnetic field increased the tumor selectivity and enhanced the tumor site accumulation and cellular uptake of MTX.CDDP@mHAPs. The released iron ions within the cancer cells trigger the Fenton reaction while the release of chemotherapy drugs, reduction of intracellular glutathione, and application of SMF aggravated the Fenton reaction, subsequently leading to the generation of reactive oxygen species (ROS) and induction of apoptosis. Therefore, Fenton magnetic-based therapy-mediated by MTX.CDDP@mHAP could be considered as a promising strategy against colon cancer with high therapeutic efficiency and biosafety.

Dual-Stimuli-Responsive Nanotheranostics for Dual-Targeting Photothermal-Enhanced Chemotherapy of Tumor

Stimuli-responsive nanotheranostics have been widely explored for precision medicine. Here, we developed a pH/light dual-stimuli-responsive nanotheranostic agent for biological/physical dual-targeting photothermal-enhanced chemotherapy of U87MG tumor. This nanotheranostic agent was composed of the RGD (Arg-Gly-Asp) peptide, melanin-coated magnetic nanoparticles (MMNs), doxorubicin (DOX), and indocyanine green (ICG), denoted as RMDI. The tumor accumulation of RMDI was simultaneously improved through biological active targeting by RGD and physical magnetic targeting by an external magnetic field at tumor tissues, which was proven by in vivo photoacoustic/magnetic resonance/fluorescence (PA/MR/FL) trimodal imaging. Under dual stimuli of the tumor acidic microenvironment and laser irradiation, both DOX and ICG were released in a controlled fashion, demonstrating impressive therapeutic outcomes against U87MG tumor both in vitro and in vivo, respectively. Owing to the synergistic photothermal/chemotherapy, the dual-stimuli-responsive and dual-targeting nanotheranostic agent completely ablated U87MG tumor in vivo without any tumor recurrence and biotoxicity. This nanotheranostic agent exhibited great potential in multimodal imaging-guided synergistic therapy of cancer.

Iron oxide nanoparticles conjugated with organic optical probes for in vivo diagnostic and therapeutic applications

The role and scope of functional inorganic nanoparticles in biomedical research is well established. Among these, iron oxide nanoparticles (IONPs) have gained maximum attention as they can provide targeting, imaging and therapeutic capabilities. Furthermore, incorporation of organic optical probes with IONPs can significantly enhance the scope and viability of their biomedical applications. Combination of two or more such applications renders multimodality in nanoparticles, which can be exploited to obtain synergistic benefits in disease detection and therapy viz theranostics, which is a key trait of nanoparticles for advanced biomedical applications. This review focuses on the use of IONPs conjugated with organic optical probe/s for multimodal diagnostic and therapeutic applications in vivo.

Advanced analysis of magnetic nanoflower measurements to leverage their use in biomedicine

Magnetic nanoparticles are an important asset in many biomedical applications ranging from the local heating of tumours to targeted drug delivery towards diseased sites. Recently, magnetic nanoflowers showed a remarkable heating performance in hyperthermia experiments thanks to their complex structure leading to a broad range of magnetic dynamics. To grasp their full potential and to better understand the origin of this unexpected heating performance, we propose the use of Kaczmarz' algorithm in interpreting magnetic characterisation measurements. It has the advantage that no a priori assumptions need to be made on the particle size distribution, contrasting current magnetic interpretation methods that often assume a lognormal size distribution. Both approaches are compared on DC magnetometry, magnetorelaxometry and AC susceptibility characterisation measurements of the nanoflowers. We report that the lognormal distribution parameters vary significantly between data sets, whereas Kaczmarz' approach achieves a consistent and accurate characterisation for all measurement sets. Additionally, we introduce a methodology to use Kaczmarz' approach on distinct measurement data sets simultaneously. It has the advantage that the strengths of the individual characterisation techniques are combined and their weaknesses reduced, further improving characterisation accuracy. Our findings are important for biomedical applications as Kaczmarz' algorithm allows to pinpoint multiple, smaller peaks in the nanostructure's size distribution compared to the monomodal lognormal distribution. The smaller peaks permit to fine-tune biomedical applications with respect to these peaks to e.g. boost heating or to reduce blurring effects in images. Furthermore, the Kaczmarz algorithm allows for a standardised data analysis for a broad range of magnetic nanoparticle samples. Thus, our approach can improve the safety and efficiency of biomedical applications of magnetic nanoparticles, paving the way towards their clinical use.

High-Throughput Screening Platform for Nanoparticle-Mediated Alterations of DNA Repair Capacity

The potential genotoxic effects of engineered nanomaterials (ENMs) may occur through the induction of DNA damage or the disruption of DNA repair processes. Inefficient DNA repair may lead to the accumulation of DNA lesions and has been linked to various diseases, including cancer. Most studies so far have focused on understanding the nanogenotoxicity of ENM-induced damages to DNA, whereas the effects on DNA repair have been widely overlooked. The recently developed fluorescence multiplex-host-cell reactivation (FM-HCR) assay allows for the direct quantification of multiple DNA repair pathways in living cells and offers a great opportunity to address this methodological gap. Herein an FM-HCR-based method is developed to screen the impact of ENMs on six major DNA repair pathways using suspended or adherent cells. The sensitivity and efficiency of this DNA repair screening method were demonstrated in case studies using primary human small airway epithelial cells and TK6 cells exposed to various model ENMs (CuO, ZnO, and Ga2O3) at subcytotoxic doses. It was shown that ENMs may inhibit nucleotide-excision repair, base-excision repair, and the repair of oxidative damage by DNA glycosylases in TK6 cells, even in the absence of significant genomic DNA damage. It is of note that the DNA repair capacity was increased by some ENMs, whereas it was suppressed by others. Overall, this method can be part of a multitier, in vitro hazard assessment of ENMs as a functional, high-throughput platform that provides insights into the interplay of the properties of ENMs, the DNA repair efficiency, and the genomic stability.

Recent advances in development of nanomedicines for multiple sclerosis diagnosis

Multiple sclerosis (MS) is a neurodegenerative disease with a high morbidity and disease burden. It is characterized by the loss of the myelin sheath, resulting in the disruption of neuron electrical signal transmissions and sensory and motor ability deficits. The diagnosis of MS is crucial to its management, but the diagnostic sensitivity and specificity are always a challenge. To overcome this challenge, nanomedicines have recently been employed to aid the diagnosis of MS with an improved diagnostic efficacy. Advances in nanomedicine-based contrast agents in magnetic resonance imaging scanning of MS lesions, and nanomedicine-derived sensors for detecting biomarkers in the cerebrospinal fluid biopsy, or analyzing the composition of exhaled breath gas, have demonstrated the potential of using nanomedicines in the accurate diagnosis of MS. This review aims to provide an overview of recent advances in the application of nanomedicines for the diagnosis of MS and concludes with perspectives of using nanomedicines for the development of safe and effective MS diagnostic nanotools.

The Use of Alternative Strategies for Enhanced Nanoparticle Delivery to Solid Tumors

Nanomaterial (NM) delivery to solid tumors has been the focus of intense research for over a decade. Classically, scientists have tried to improve NM delivery by employing passive or active targeting strategies, making use of the so-called enhanced permeability and retention (EPR) effect. This phenomenon is made possible due to the leaky tumor vasculature through which NMs can leave the bloodstream, traverse through the gaps in the endothelial lining of the vessels, and enter the tumor. Recent studies have shown that despite many efforts to employ the EPR effect, this process remains very poor. Furthermore, the role of the EPR effect has been called into question, where it has been suggested that NMs enter the tumor via active mechanisms and not through the endothelial gaps. In this review, we provide a short overview of the EPR and mechanisms to enhance it, after which we focus on alternative delivery strategies that do not solely rely on EPR in itself but can offer interesting pharmacological, physical, and biological solutions for enhanced delivery. We discuss the strengths and shortcomings of these different strategies and suggest combinatorial approaches as the ideal path forward.

Advances in Magnetic Nanoparticle-Mediated Cancer Immune-Theranostics

Cancer immunotherapy is a cutting-edge strategy that eliminates cancer cells by amplifying the host's immune system. However, the low response rate and risks of inducing systemic toxicity have raised uncertainty in the treatment. Magnetic nanoparticles (MNPs) as a versatile theranostic tool can be used to target delivery of multiple immunotherapeutics and monitor cell/tissue responses. These capabilities enable the real-time characterization of the factors that contribute to immunoactivity so that future treatments can be optimized. The magnetic properties of MNPs further allow the implementation of magnetic navigation and magnetic hyperthermia for boosting the efficacy of immunotherapy. The multimodal approach opens an avenue to induce robust immune responses, minimize safety issues, and monitor immune activities simultaneously. Thus, the object of this review is to provide an overview of the burgeoning fields and to highlight novel technologies for next-generation immunotherapy. The review further correlates the properties of MNPs with the latest treatment strategies to explore the crosstalk between magnetic nanomaterials and the immune system. This comprehensive review of MNP-derived immunotherapy covers the obstacles and opportunities for future development and clinical translation.

Recent Progress in the Synergistic Combination of Nanoparticle-Mediated Hyperthermia and Immunotherapy for Treatment of Cancer

Immunotherapy has demonstrated great clinical success in certain cancers, driven primarily by immune checkpoint blockade and adoptive cell therapies. Immunotherapy can elicit strong, durable responses in some patients, but others do not respond, and to date immunotherapy has demonstrated success in only a limited number of cancers. To address this limitation, combinatorial approaches with chemo- and radiotherapy have been applied in the clinic. Extensive preclinical evidence suggests that hyperthermia therapy (HT) has considerable potential to augment immunotherapy with minimal toxicity. This progress report will provide a brief overview of immunotherapy and HT approaches and highlight recent progress in the application of nanoparticle (NP)-based HT in combination with immunotherapy. NPs allow for tumor-specific targeting of deep tissue tumors while potentially providing more even heating. NP-based HT increases tumor immunogenicity and tumor permeability, which improves immune cell infiltration and creates an environment more responsive to immunotherapy, particularly in solid tumors.

Magnetic microgels and nanogels: Physical mechanisms and biomedical applications

Soft micro- and nanostructures have been extensively developed for biomedical applications. The main focus has been on multifunctional composite materials that combine the advantages of hydrogels and colloidal particles. Magnetic microgels and nanogels can be realized by hybridizing stimuli-sensitive gels and magnetic nanoparticles. They are of particular interest since they can be controlled in a wide range of biological environments by using magnetic fields. In this review, we elucidate physical principles underlying the design of magnetic microgels and nanogels for biomedical applications. Particularly, this article provides a comprehensive and conceptual overview on the correlative structural design and physical functionality of the magnetic gel systems under the concept of colloidal biodevices. To this end, we begin with an overview of physicochemical mechanisms related to stimuli-responsive hydrogels and transport phenomena and summarize the magnetic properties of inorganic nanoparticles. On the basis of the engineering principles, we categorize and summarize recent advances in magnetic hybrid microgels and nanogels, with emphasis on the biomedical applications of these materials. Potential applications of these hybrid microgels and nanogels in anticancer treatment, protein therapeutics, gene therapy, bioseparation, biocatalysis, and regenerative medicine are highlighted. Finally, current challenges and future opportunities in the design of smart colloidal biodevices are discussed.

Personalized dynamic transport of magnetic nanorobots inside the brain vasculature

Delivering specific bioactive agents with sufficient bioavailability to the targeted brain area across blood brain barrier remains a big challenge. Magnetically driven nanorobots have demonstrated their potential for controlled drug delivery. However, the dynamic transport of these nanorobots inside each individual's brain vasculature is not yet well studied. Addressing this is a critical step forward to controlled drug delivery for non-invasive brain therapeutics. In this paper, we develop an analytical model describing the personalized dynamic transport of spherical magnetic nanorobots inside the brain vasculature reconstructed from the patient's angiography images. By inverting the transporting process, we first design the patient-specific transport path based on the reconstructed vascular model, and then calculate the magnetic force required to drive these nanorobots from the analytical model. Also, a finite element model is created to simulate the inverse design process, which implies that the delivery efficiency of these magnetically driven nanorobots to the targeted brain area can be increased by 20% and almost 95% nanorobots arrive at the desired vessel walls. In the end, a simplified brain vascular model is printed using PolyJet 3D 750 to demonstrate the dynamic transport of these nanorobots toward the targeted site. The proposed theoretical modeling, numerical simulation and experimental validation lay solid foundation toward non-invasive brain therapeutics with maximal accuracy and minimal side effects.

Etoposide-Bound Magnetic Nanoparticles Designed for Remote Targeting of Cancer Cells Disseminated Within Cerebrospinal Fluid Pathways

Magnetic nanoparticles (MNPs) have potential for enhancing drug delivery in selected cancer patients, including those which have cells that have disseminated within cerebrospinal fluid (CSF) pathways. Here, we present data related to the creation and in vitro use of new two-part MNPs consisting of magnetic gold-iron alloy cores which have streptavidin binding sites, and are coated with biotinylated etoposide. Etoposide was chosen due to its previous use in the CSF and ease of biotinylation. Etoposide magnetic nanoparticles (“Etop-MNPs”) were characterized by several different methods, and moved at a distance by surface-walking of MNP clusters, which occurs in response to a rotating permanent magnet. Human cell lines including D283 (medulloblastoma), U138 (glioblastoma), and H2122 (lung adenocarcinoma) were treated with direct application of Etop-MNPs (and control particles), and after remote particle movement. Cell viability was determined by MTT assay and trypan blue exclusion. Results indicated that the biotinylated etoposide was successfully bound to the base MNPs, with the hybrid particle attaining a maximum velocity of 0.13 ± 0.018 cm/sec. Etop-MNPs killed cancer cells in a dose-dependent fashion, with 50 ± 6.8% cell killing of D283 cells (for example) with 24 h of treatment after remote targeting. U138 and H2122 cells were found to be even more susceptible to the killing effect of Etop-MNPs than D283 cells. These findings indicate that the novel Etop-MNPs have a cytotoxic effect, and can be moved relatively rapidly at physiologic distances, using a rotating magnet. While further testing is needed, intrathecal administration of Etop-MNPs holds promise for magnetically-enhanced eradication of cancer cells distributed within CSF pathways, particularly if given early in the course of the disease.