Photoregulated Cross-Linking of Superparamagnetic Iron Oxide Nanoparticle (SPION) Loaded Hybrid Nanovectors with Synergistic Drug Release and Magnetic Resonance (MR) Imaging Enhancement

From detection to elimination: iron-based nanomaterials driving tumor imaging and advanced therapies

Iron-based nanomaterials (INMs), due to their particular magnetic property, excellent biocompatibility, and functionality, have been developed into powerful tools in both tumor diagnosis and therapy. We give an overview here on how INMs such as iron oxide nanoparticles, element-doped nanocomposites, and iron-based organic frameworks (MOFs) display versatility for tumor imaging and therapy improvement. In terms of imaging, INMs improve the sensitivity and accuracy of techniques such as magnetic resonance imaging (MRI) and photoacoustic imaging (PAI) and support the development of multimodal imaging platforms. Regarding treatment, INMs play a key role in advanced strategies such as immunotherapy, magnetic hyperthermia, and synergistic combination therapy, which effectively overcome tumor-induced drug resistance and reduce systemic toxicity. The integration of INMs with artificial intelligence (AI) and radiomics further expands its capabilities for precise tumor identification, and treatment optimization, and amplifies treatment monitoring. INMs now link materials science with advanced computing and clinical innovations to enable next-generation cancer diagnostics and therapeutics.

Micelle-like Nanoparticles for Drug Delivery and Magnetically Enhanced Tumor Chemotherapy

Using the coordination bonds between transition metal atoms and electron-rich functional groups, we synthesized two kinds of micelle-like nanoparticles. Using magnetic Fe3O4 as the core, poly(methyl methacrylate) (PMMA) and poly(acrylic acid) (PAA) brushes were grafted via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET-ATRP), which formed micelle-like magnetic nanoparticles Fe3O4/PAA-PMMA with a hydrophobic outer layer and Fe3O4/PMMA-PAA with a hydrophilic outer layer. Both the micelle-like nanoparticles had amphiphilic properties and can be used to load hydrophilic or hydrophobic drugs. Even loaded with hydrophobic drugs, the micelle-like nanoparticles can still be dispersed in aqueous solution, and Fe3O4/PAA-PMMA had a higher loading content. As the drug carrier, these two micelle-like nanoparticles can be used for magnetically targeted drug delivery and magnetic resonance imaging due to superparamagnetic Fe3O4. In addition, due to the magnetic retention effect, the drug-loaded micelle-like nanoparticles remained at the tumor site, increasing the local drug concentration. At the same time, the drug-loaded micelle-like nanoparticles generated a magnetocaloric effect under the alternating magnetic field, which not only killed tumor cells by magnetic hyperthermia but also promoted the rapid release of drugs at the tumor site. In general, magnetically enhanced chemotherapy showed the best therapeutic effect on tumors.

Moist Heat Synthesis of Magnetic EGCG-Cappedα-Fe2O3 Nanoparticles and Their In Vitro and In Silico Interactions with Pristine HSA- and NDM-1-Producing Bacteria

A simple, facile, moist-heating (e.g., autoclave), one-step procedure for EGCG-mediated biosynthesis of narrow-size magnetic iron oxide (α-Fe2O3) nanoparticles (EGCG-MINPs) was developed. The influence of pH of the reaction mixture over the size distribution of as-synthesized EGCG-MINPs was investigated systematically by employing UV-visible (UV-vis) spectroscopy and dynamic light scattering (DLS)-based hydrodynamic size, surface charge (zeta-potential), and polydispersity index (PDI). The FE-SEM, TEM, and XRD characterizations revealed that the EGCG-MINPs synthesized at pH 5.0 were in the size range of 6.20-16.7 nm and possess well-crystalline hexagonal shaped nanostructures of hematite (α-Fe2O3) crystal phase. The role of EGCG in Fe3+ ion reduction and EGCG-MINP formation was confirmed by FTIR analysis. The VSM analysis has revealed that EGCG-MINPs were highly magnetic nanostructures with the hysteretic feature of saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) as 33.64 emu/g, 12.18 emu/g, and 0.33 Oe, respectively. Besides, significant (p < 0.001) dose-dependent (250-1000 μg/mL) antibacterial and antibiofilm activities against the NDM-1-producing Gram-negative Escherichia coli (AK-33), Klebsiella pneumoniae (AK-65), Pseudomonas aeruginosa (AK-66), and Shigella boydii (AK-67) bacterial isolates warranted the as-synthesized EGCG-MINPs as a promising alternative for clinical management of chronic bacterial infections in biomedical settings. In addition, molecular docking experiments revealed that compared to free Fe3+ and EGCG alone, the EGCG-MINPs or Fe-EGCG complex possess significantly high binding affinity toward HSA and hence can be considered as promising biocompatible nanodrug carriers in in vivo drug delivery systems.

Superparamagnetic Iron Oxide Nanoparticles (SPION): From Fundamentals to State-of-the-Art Innovative Applications for Cancer Therapy

Despite significant advances in cancer therapy over the years, its complex pathological process still represents a major health challenge when seeking effective treatment and improved healthcare. With the advent of nanotechnologies, nanomedicine-based cancer therapy has been widely explored as a promising technology able to handle the requirements of the clinical sector. Superparamagnetic iron oxide nanoparticles (SPION) have been at the forefront of nanotechnology development since the mid-1990s, thanks to their former role as contrast agents for magnetic resonance imaging. Though their use as MRI probes has been discontinued due to an unfavorable cost/benefit ratio, several innovative applications as therapeutic tools have prompted a renewal of interest. The unique characteristics of SPION, i.e., their magnetic properties enabling specific response when submitted to high frequency (magnetic hyperthermia) or low frequency (magneto-mechanical therapy) alternating magnetic field, and their ability to generate reactive oxygen species (either intrinsically or when activated using various stimuli), make them particularly adapted for cancer therapy. This review provides a comprehensive description of the fundamental aspects of SPION formulation and highlights various recent approaches regarding in vivo applications in the field of cancer therapy.

New Water-Soluble Magnetic Field-Induced Drug Delivery System Obtained Via Preferential Molecular Marriage over Narcissistic Self-Sorting

Nanomaterials that respond to stimuli are of considerable interest for drug delivery applications. Drug delivery has been a leading challenge when it comes to the externally triggered controlled release of hydrophobic drugs. The present paper describes a unique arrangement of polymers in a competitive environment derived from the dynamic self-sorting behavior of the hydrophobic chains of amphiphilic mPEG-PLLA and poly-l-lactic acid (PLLA)-coated iron oxide nanoparticles IONP@PLLA to achieve a core-shell structure in which the hydrophobic PLLA part acts as a dense core and poly(ethylene glycol) (PEG) as an uncrowded shell. By using irreversible covalent interactions created by hydrophobic polymer-functionalized IONPs, it was possible to selectively form socially self-sorted nanocarriers (SS-NCs) with a higher hydrophobic core than the hydrophilic shell over narcissistic self-sorted nanocarriers (NS-NCs), that is, homo-micelles of amphiphilic polymers. The higher hydrophobic core of SS-NCs is indeed helpful in achieving higher drug [doxorubicin (DOX)] loading and encapsulation efficiencies of around 17 and 90%, respectively, over 10.3 and 65.6% for NS-NCs. Furthermore, due to the presence of IONPs and the densely packed hydrophobic compartments, the controlled release of DOX was facilitated by direct magnetism and temperature stimulation when an alternating magnetic field (AMF) was applied. An appreciably higher rate of drug release (∼50%) than that without AMF (∼18%) was achieved under ambient conditions in 24 h. The present study, therefore, proposes a new drug delivery system that exceeds homo-micelles and adds an extra feature of manipulating drug release through magnetism and temperature, that is, hyperthermia.

Living Covalent-Anionic-Radical Polymerization via a Barbier Strategy

The developments of the living alkene polymerization method have achieved great progress and enabled the precise synthesis of important polyalkenes with controlled molecular weight, molecular weight distribution, and architecture through an anionic, cationic or radical strategy. However, it is still challenging to develop a living alkene polymerization method through an all-in-one strategy where anionic and radical characteristics are merged into one polymerization species. Here, a versatile living polymerization method is reported by introducing a well-established all-in-one covalent-anionic-radical Barbier strategy into a living polymerization. Through this living covalent-anionic-radical Barbier polymerization (Barbier CARP), narrow distributed polystyrenes, with Đ as low as 1.05, are successfully prepared under mild conditions with a full monomer conversion by using wide varieties of organohalides, for example, alkyl, benzyl, allyl, and phenyl halides, as initiators with Mg in one pot. This living covalent-anionic-radical polymerization via a Barbier strategy expands the methodology library of polymer chemistry and enables living polymerization with an unconventional polymerization mode.

Self-Assembly of Upconversion Nanoparticles Based Materials and Their Emerging Applications

In the past few decades, significant progress of the conventional upconversion nanoparticles (UCNPs) based nanoplatform has been achieved in many fields, and with the development of nanoscience and nanotechnology, more and more complex situations need a UCNPs based nanoplatform having multifunctions for specific multimodal or multiplexed applications. Through self-assembly, different UCNPs or UCNPs with other materials could be combined together within an entity. It is more like an ideal UCNPs nanoplatform, a unique system with the properties defined by its individual components as well as by the morphology of the composite. Various designs can show their different desired properties depending on the application situation. This review provides a complete summary on the optimization of the synthesis method for the recently designed UCNPs assemblies and summarizes various applications, including dual-modality cell imaging, molecular delivery, detection, and programmed control therapy. The challenges and limitations the UCNPs assembly faces and the potential solutions in this field are also presented.

An update on the applications and characteristics of magnetic iron oxide nanoparticles for drug delivery

INTRODUCTION

In the field of drug delivery, controlling the release of therapeutic substances at localized targets has become a primary focus of medical research, especially in the field of cancer treatment. Magnetic nanoparticles are one of the most promising drug carriers thanks to their biocompatibility and (super)paramagnetic properties. These properties allow for the combination between imaging modalities and specific release of drugs at target sites using either local stimulus (i.e. pH, conjugation of biomarkers, …) or external stimulus (i.e. external magnetic field).

AREAS COVERED

This review provides an update on recent advances with the development of targeted drug delivery systems based on magnetic nanoparticles (MNPs). This overview focuses on active targeting strategies and systems combining both imaging and therapeutic modalities (i.e. theranostics). If most of the examples concern the particular case of cancer therapy, the possibility of using MNPs for other medical applications is also discussed.

EXPERT OPINION

The development of clinically relevant drug delivery systems based on magnetic nanoparticles is driven by advantages stemming from their remarkable properties (i.e. easy preparation, facile chemical functionalization, biocompatibility, low toxicity and superior magnetic responsiveness). This literature review shows that drug carriers based on magnetic nanoparticles can be efficiently used for the controlled release of drug at targeted locations mediated by various stimuli. Advances in the field should lead to the implementation of such systems into clinical trials, especially systems enabling drug tracking in the body.

Thermo/glutathione-sensitive release kinetics of heterogeneous magnetic micro-organogel prepared by sono-catalysis

To improve the loading and delivery for hydrophobic drugs and optimize the release efficiency in tumor microenvironment, a novel core-shell magnetic micro-organogel carrier was successfully prepared by a sono-catalysis process in the study. As-synthesized magnetic micro-organogel had an appropriate dispersibility in water owing to the hydrophilicity of protein shell and could be kept steadily with a well-defined spherical morphology owing to the three-dimensional gel structure of oil core, and it promised an accessible targeted drug delivery owing to its good magnetism-mediated motion ability. Moreover, the magnetic micro-organogel showed a high loading efficiency up to 94.22% for coumarin 6 which was dissolved into the micro-organogel as a model hydrophobic drug. More importantly, the release kinetics revealed that the magnetic micro-organogel had a thermo-sensitive and glutathione (GSH)-sensitive ability to control the drug release, and proved that its release mechanisms referred to the combination of erosion, diffusion and degradation.

Effects of DC Magnetic Fields on Magnetoliposomes

The potential use of magnetic nanoparticles (MNPs) in biomedicine as magnetic resonance, drug delivery, imagenology, hyperthermia, biosensors, and biological separation has been studied in different laboratories. One of the challenges on MNP elaboration for biological applications is the size, biocompatibility, heat efficiency, stabilization in physiological conditions, and surface coating. Magnetoliposome (ML), a lipid bilayer of phospholipids encapsulating MNPs, is a system used to reduce toxicity. Encapsulated MNPs can be used as a potential drug and a gene delivery system, and in the presence of magnetic fields, MLs can be accumulated in a target tissue by a strong gradient magnetic field. Here, we present a study of the effects of DC magnetic fields on encapsulated MNPs inside liposomes. Despite their widespread applications in biotechnology and environmental, biomedical, and materials science, the effects of magnetic fields on MLs are unclear. We use a modified coprecipitation method to synthesize superparamagnetic nanoparticles (SNPs) in aqueous solutions. The SNPs are encapsulated inside phospholipid liposomes to study the interaction between phospholipids and SNPs. Material characterization of SNPs reveals round-shaped nanoparticles with an average size of 12 nm, mainly magnetite. MLs were prepared by the rehydration method. After formation, we found two types of MLs: one type is tense with SNPs encapsulated and the other is a floppy vesicle that does not show the presence of SNPs. To study the response of MLs to an applied DC magnetic field, we used a homemade chamber. Digitalized images show encapsulated SNPs assembled in chain formation when a DC magnetic field is applied. When the magnetic field is switched off, it completely disperses SNPs. Floppy MLs deform along the direction of the external applied magnetic field. Solving the relevant magnetostatic equations, we present a theoretical model to explain the ML deformations by analyzing the forces exerted by the magnetic field over the surface of the spheroidal liposome. Tangential magnetic forces acting on the ML surface result in a press force deforming MLs. The type of deformations will depend on the magnetic properties of the mediums inside and outside the MLs. The model predicts a coexistence region of oblate-prolate deformation in the zone where χ = 1. We can understand the chain formation in terms of a dipole-dipole interaction of SNP.

Coordinating External and Built-In Triggers for Tunable Degradation of Polymeric Nanoparticles via Cycle Amplification

The selective activation of nanovectors in pathological tissues is of crucial importance to achieve optimized therapeutic outcomes. However, conventional stimuli-responsive nanovectors lack sufficient sensitivity because of the slight difference between pathological and normal tissues. To this end, the development of nanovectors capable of responding to weak pathological stimuli is of increasing interest. Herein, we report the fabrication of amphiphilic polyurethane nanoparticles containing both external and built-in triggers. The activation of external triggers leads to the liberation of highly reactive primary amines, which subsequently activates the built-in triggers with the release of more primary amines in a positive feedback manner, thereby triggering the degradation of micellar nanoparticles in a cycle amplification model. The generality and versatility of the cycle amplification concept have been successfully verified using three different triggers including reductive milieu, light irradiation, and esterase. We demonstrate that these stimuli-responsive nanoparticles show self-propagating degradation performance even in the presence of trace amounts of external stimuli. Moreover, we confirm that the esterase-responsive nanoparticles can discriminate cancer cells from normal ones by amplifying the esterase stimulus that is overexpressed in cancer cells, thereby enabling the selective release of encapsulated payloads and killing cancer cells. This work presents a robust strategy to fabricate stimuli-responsive nanocarriers with highly sensitive property toward external stimuli, showing promising applications in cancer therapy with minimized side effects.

Magnetic Nanoparticle Composites: Synergistic Effects and Applications

Composite materials are made from two or more constituent materials with distinct physical or chemical properties that, when combined, produce a material with characteristics which are at least to some degree different from its individual components. Nanocomposite materials are composed of different materials of which at least one has nanoscale dimensions. Common types of nanocomposites consist of a combination of two different elements, with a nanoparticle that is linked to, or surrounded by, another organic or inorganic material, for example in a core-shell or heterostructure configuration. A general family of nanoparticle composites concerns the coating of a nanoscale material by a polymer, SiO2 or carbon. Other materials, such as graphene or graphene oxide (GO), are used as supports forming composites when nanoscale materials are deposited onto them. In this Review we focus on magnetic nanocomposites, describing their synthetic methods, physical properties and applications. Several types of nanocomposites are presented, according to their composition, morphology or surface functionalization. Their applications are largely due to the synergistic effects that appear thanks to the co-existence of two different materials and to their interface, resulting in properties often better than those of their single-phase components. Applications discussed concern magnetically separable catalysts, water treatment, diagnostics-sensing and biomedicine.

Multifunctional theranostic nanoparticles for biomedical cancer treatments - A comprehensive review

Modern-day search for the novel agents (their preparation and consequent implementation) to effectively treat the cancer is mainly fuelled by the historical failure of the conventional treatment modalities. Apart from that, the complexities such as higher rate of cell mutations, variable tumor microenvironment, patient-specific disparities, and the evolving nature of cancers have made this search much stronger in the latest times. As a result of this, in about two decades, the theranostic nanoparticles (TNPs) - i.e., nanoparticles that integrate therapeutic and diagnostic characteristics - have been developed. The examples for TNPs include mesoporous silica nanoparticles, luminescence nanoparticles, carbon-based nanomaterials, metal nanoparticles, and magnetic nanoparticles. These TNPs have emerged as single and powerful cancer-treating multifunctional nanoplatforms, as they widely provide the necessary functionalities to overcome the previous/conventional limitations including lack of the site-specific delivery of anti-cancer drugs, and real-time continuous monitoring of the target cancer sites while performing therapeutic actions. This has been mainly possible due to the association of the as-developed TNPs with the already-available unique diagnostic (e.g., luminescence, photoacoustic, and magnetic resonance imaging) and therapeutic (e.g., photothermal, photodynamic, hyperthermia therapy) modalities in the biomedical field. In this review, we have discussed in detail about the recent developments on the aforementioned important TNPs without/with targeting ability (i.e., attaching them with ligands or tumor-specific antibodies) and also the strategies that are implemented to increase their tumor accumulation and to enhance their theranostic efficacies for effective biomedical cancer treatments.

Microfluidic platform for synthesis and optimization of chitosan-coated magnetic nanoparticles in cisplatin delivery

In this study, magnetic core/chitosan shell Nanoparticles (NPs) containing cisplatin were synthesized via cisplatin complexation with tripolyphosphate as the chitosan crosslinker using two different procedures: a conventional batch flow method and a microfluidic approach. An integrated microfluidic device composed of three stages was developed to provide precise and highly controllable mixing. The comparison of the results revealed that NPs synthesized in microchannels were monodisperse 104 ± 14.59 nm (n = 3) in size with optimal morphological characteristics, whereas polydisperse 423 ± 53.33 nm (n = 3) nanoparticles were obtained by the conventional method. Furthermore, cisplatin was loaded in NPs without becoming inactivated, and the microfluidic technique demonstrated higher encapsulation efficiency, controlled release, and consequently lower IC50 values during exposure to the A2780 cell line proving that microfluidic synthesized NPs were able to enter the cells and release the drug more efficiently. The developed microfluidic platform presents valuable features that could potentially provide the clinical translation of NPs in drug delivery.

Embedding of superparamagnetic iron oxide nanoparticles into membranes of well-defined poly(ethylene oxide)-block-poly(ε-caprolactone) nanoscale magnetovesicles as ultrasensitive MRI probes of membrane bio-degradation

The present study reports the preparation of poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) polymer vesicles via a nanoprecipitation method and the loading of two different size hydrophobically coated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles (a magnetic core size of 4.2 nm and 7.6 nm) into the membrane of these nanovesicles, whose thickness was measured precisely by small angle neutron scattering (SANS). Spherical nano-assemblies with a high USPIO payload and a diameter close to 150 nm were obtained as confirmed by dynamic light scattering (DLS), transmission electron microscopy (TEM) and cryo-TEM. The vesicular structure of these hybrid nano-assemblies was confirmed by multi-angle light scattering (MALS) measurements. Their magnetic properties were evaluated by T1 and T2 measurements (20 and 60 MHz) and by nuclear magnetic relaxation dispersion (NMRD) profiles. The size of USPIO entrapped in the membranes of PEO-b-PCL vesicles has a strong impact on their magnetic properties. It affects both their longitudinal and their transverse relaxivities and thus their magnetic resonance imaging (MRI) sensitivity. Acid-catalyzed hydrolysis of the PCL membrane also influences their relaxivities as shown by measurements carried out at pH 7 vs. pH 5. This property was used to monitor the membrane hydrolytic degradation in vitro, as a proof of concept of potential monitoring of drug delivery by nanomedicines in vivo and non-invasively, by MRI.

Responsive polymers for medical diagnostics

Stimulus-responsive polymers have been used in improving the efficacy of medical diagnostics through different approaches including enhancing the contrast in imaging techniques and promoting the molecular recognition in diagnostic assays. This review overviews the mechanisms of stimulus-responsive polymers in response to external stimuli including temperature, pH, ion, light, etc. The applications of responsive polymers in magnetic resonance imaging, capture and purification of biomolecules through protein-ligand recognition and lab-on-a-chip technology are discussed.

Heavily superparamagnetic magnetite-loaded polymeric worm-like micelles that have an ultrahigh T2 relaxivity

Composite worm-like micelles with an ultrahigh T₂ relaxivity fabricated via two-stage self-assembly of SMNPs guided by PEG-b-P4VP and DNA.

Iron/iron oxide nanoparticles: advances in microbial fabrication, mechanism study, biomedical, and environmental applications

Microbially synthesized iron oxide nanoparticles (FeONPs) hold great potential for biomedical, clinical, and environmental applications owing to their several unique features. Biomineralization, a process that exists in almost every living organism playing a significant role in the fabrication of FeONPs through the involvement of 5-100 nm sized protein compartments such as dodecameric (Dps), ferritin, and encapsulin with their diameters 9, 12, and ∼32 nm, respectively. This contribution provides a detailed overview of the green synthesis of FeONPs by microbes and their applications in biomedical and environmental fields. The first part describes our understanding in the biological fabrication of zero-valent FeONPs with special emphasis on ferroxidase (FO) mediated series of steps involving in the translocation, oxidation, nucleation, and storage of iron in Dps, ferritin, and encapsulin protein nano-compartments. Secondly, this review elaborates the significance of biologically synthesized FeONPs in biomedical science for the detection, treatment, and prevention of various diseases. Thirdly, we tried to provide the recent advances of using FeONPs in the environmental process, e.g. detection, degradation, remediation and treatment of toxic pesticides, dyes, metals, and wastewater.

Biosensors for Epilepsy Management: State-of-Art and Future Aspects

Epilepsy is a serious neurological disorder which affects every aspect of patients’ life, including added socio-economic burden. Unfortunately, only a few suppressive medicines are available, and a complete cure for the disease has not been found yet. Excluding the effectiveness of available therapies, the timely detection and monitoring of epilepsy are of utmost priority for early remediation and prevention. Inability to detect underlying epileptic signatures at early stage causes serious damage to the central nervous system (CNS) and irreversible detrimental variations in the organ system. Therefore, development of a multi-task solving novel smart biosensing systems is urgently required. The present review highlights advancements in state-of-art biosensing technology investigated for epilepsy diseases diagnostics and progression monitoring or both together. State of art epilepsy biosensors are composed of nano-enabled smart sensing platform integrated with micro/electronics and display. These diagnostics systems provide bio-information needed to understand disease progression and therapy optimization timely. The associated challenges related to the development of an efficient epilepsy biosensor and vision considering future prospects are also discussed in this report. This review will serve as a guide platform to scholars for understanding and planning of future research aiming to develop a smart bio-sensing system to detect and monitor epilepsy for point-of-care (PoC) applications.

pH-Responsive polyelectrolyte coated gadolinium oxide-doped mesoporous silica nanoparticles (Gd2O3@MSNs) for synergistic drug delivery and magnetic resonance imaging enhancement

Theranostic platforms that combine therapeutic and imaging modalities have received increasing interest.

Evaluation of non-targeting, C- or N-pH (low) insertion peptide modified superparamagnetic iron oxide nanoclusters for selective MRI of liver tumors and their potential toxicity in cirrhosis

Superparamagnetic iron oxide nanoclusters (SPIONs) modified with pH (low) insertion peptide (pHLIP) could be advantageous for magnetic resonance imaging (MRI) diagnosis of liver tumors at the early stage due to their unique responsiveness to the tumor acidic microenvironment when tumor markers are unknown. However, many critical aspects including the effectiveness of selective MRI in liver tumors, types of delivery and the potential safety profile in cirrhosis need to be fully evaluated. In this study, we report the evaluation of non-targeting, C- or N-pHLIP modified SPIONs as the contrast agent for selective MRI of liver tumors and their potential toxicity profile in cirrhosis. It was found that N-pHLIP modified SPIONs did not result in the loss of liver tumor in the T2-weight MRI but provided additional dynamic details of tumor structures that would enhance the diagnosis of liver tumors at a small size below 8 mm. In addition, an enhanced safety profile was found for N-pHLIP modified SPIONs with almost fully recoverable impact in cirrhosis. In contrast, the poly-d-lysine assembled SPIONs and C-terminus linked pHLIP SPIONs had non-tumor specific MRI contrast enhancement and potential safety risks in cirrhosis due to the iron overload post injection. All these results implied the promising potential of N-terminus linked pHLIP SPIONs as an MRI contrast agent for the diagnosis of liver tumors.

The acid-responsive pHLIP modified SPION as an MRI contrast agent for liver cancer diagnosis requires the validation of both the tumor-specific enhancement and a safe profile in cirrhosis.

Low intensity sonosynthesis of iron carbide@iron oxide core-shell nanoparticles

Here we demonstrate a simple method for the organic sonosynthesis of stable Iron Carbide@Iron Oxide core-shell nanoparticles (ICIONPs) stabilized by oleic acid surface modification. This robust synthesis route is based on the sonochemistry reaction of organometallic precursor like Fe(CO)₅ in octanol using low intensity ultrasonic bath. As obtained, nanoparticles diameter sizes were measured around 6.38 nm ± 1.34 with a hydrodynamic diameter around 25 nm and an estimated polydispersity of 0.27. Core-Shell structure of nanoparticles was confirmed using HR-TEM and XPS characterization tools in which a core made up of iron carbide (Fe₃C) and a shell of magnetite (γ-Fe₂O₃) was found. The overall nanoparticle presented ferromagnetic behavior at 4 K by SQUID. With these characteristics, the ICIONPs can be potentially used in various applications such as theranostic agent due to their properties obtained from the iron oxides and iron carbide phases.

Zn2+ Ion Surface Enrichment in Doped Iron Oxide Nanoparticles Leads to Charge Carrier Density Enhancement

Here, we report the development of monodisperse Zn-doped iron oxide nanoparticles (NPs) with different amounts of Zn (Zn _x Fe_3-x O₄, 0 < x < 0.43) by thermal decomposition of a mixture of zinc and iron oleates. The as-synthesized NPs show a considerable fraction of wüstite (FeO) which is transformed to spinel upon 2 h oxidation of the NP reaction solutions. At any Zn doping amounts, we observed the enrichment of the NP surface with Zn²⁺ ions, which is enhanced at higher Zn loadings. Such a distribution of Zn²⁺ ions is attributed to the different thermal decomposition profiles of Zn and Fe oleates, with Fe oleate decomposing at much lower temperature than that of Zn oleate. The decomposition of Zn oleate is, in turn, catalyzed by a forming iron oxide phase. The magnetic properties were found to be strongly dependent on the Zn doping amounts, showing the saturation magnetization to decrease by 9 and 20% for x = 0.05 and 0.1, respectively. On the other hand, X-ray photoelectron spectroscopy near the Fermi level demonstrates that the Zn_0.05Fe_2.95O₄ sample displays a more metallic character (a higher charge carrier density) than undoped iron oxide NPs, supporting its use as a spintronic material.

Synthesis of Redox-Responsive Core Cross-Linked Micelles Carrying Optically Active Helical Poly(phenyl isocyanide) Arms and Their Applications in Drug Delivery

In this manuscript, we designed and synthesized three core cross-linked micelles (M-5L, P-5L, and P-5D) with redox-responsive disulfide bonds in the core and carrying optically active helical polyisocyanide arms. Their arms were different in the helicity of the main chain and the chirality of the side groups. These micelles showed excellent redox-responsiveness to reducing agent. However, because of the different chiralities of the arms, the three micelles exhibited different performances in drug delivery and controlled release. The M-5L micelle carrying left-handed helical arms showed better therapeutic effect than the other two due to the rapid cell membrane permeability.

Molecular encapsulator-appended poly(vinyl alcohol) shroud on ferrite nanoparticles. Augmented cancer-drug loading and anticancer property

Magnetic nanoparticles (MNPs) have the potency to deliver cancer drugs assisted by the application of a magnetic field. In this paper, we present the design of magnesium ferrite nanoparticles of size suitable for drug delivery. A coating polymer, poly(vinyl alcohol), tethered with a tapered cone-shaped cyclic oligosachcharide, β-cyclodextrin (β-CD) is synthesized and used to wrap and disperse the MNPs. The magnetic properties are explored using vibrating sample magnetometry and Mössbauer spectroscopy. The ∑130 nm MNPs, shrouded with the PVA-CD conjugate allows a high amount of the cancer drug, camptothecin, to be loaded on the nanocarrier. Cytotoxicity studies reveal that the loaded drug retains its potency against HEK 293 cells and the cells are sensitive to the treatment by the drug-loaded nanocarrier.

Photoresponsive Nanovehicle for Two Independent Wavelength Light-Triggered Sequential Release of P-gp shRNA and Doxorubicin To Optimize and Enhance Synergistic Therapy of Multidrug-Resistant Cancer

Prerelease of RNA molecules than chemotherapeutic drugs with a sufficient interval is a vital prerequisite for RNA/drug co-delivery strategy to overcome multidrug resistance (MDR) of cancer cells, but how to precisely control their release at different time points is still a grand challenge up to now. This study aims to on-demand remotely manipulate RNA and drug release in real time through single delivery system to sequentially play their respective roles for optimizing and enhancing their synergistic antitumor effects. To this end, a photoresponsive mesoporous silica nanoparticle (PMSN) is fabricated as a co-delivery vehicle of P-glycoprotein (P-gp) short-hairpin RNA (shRNA) and photocaged prodrug of doxorubicin (DOX), by which the orthogonal and sequential release of shRNA and DOX can be achieved using an external light. In our design, the cationic poly[2-( N, N-dimethylaminoethyl)methacrylate] is introduced onto the PMSN surface through a light-sensitive coumarin ester derivative linker to adsorb P-gp shRNA, whereas the photocleavable o-nitrobenzyl ester derivative-caged DOX is loaded into the inner pores of the PMSN. The PMSN is found to be effectively internalized by MDR cancer cells, and the release of the shRNA and DOX is demonstrated to be independently regulated by 405 and 365 nm light irradiations due to selectively cleaved coumarin and o-nitrobenzyl ester, resulting in enhanced drug retention, and finally bring out optimized and significantly improved chemotherapeutic effects both in vitro and in vivo for MDR cancer treatment, which might hold extensive application prospects in MDR cancer treatment in future.

Surface design and preparation of multi-functional magnetic nanoparticles for cancer cell targeting, therapy, and imaging

Recently, theranostic candidates based on superparamagnetic iron oxide nanoparticles (SPIONs) providing the combination of therapy and diagnosis have become one of the most promising system in cancer research. However, poor stability, premature drug release, lack of specific tumor cell targeting, and complicated multi-step synthesis processes still hinder them for potential clinical applications. In this research, the multi-functional magnetic nanoparticles (MNPs-DOX) were prepared via a simple assembly process for targeted delivery of doxorubicin (DOX) and enhanced magnetic resonance (MR) imaging detection. Firstly, the multi-functional copolymer coating, polyamidoamine (PAMAM), was designed and synthesized by Michael addition reaction, where N,N-bis(acryloyl)cystamine served as backbone linker, and DOX, dopamine (DA), and polyethylene glycol (PEG) acted as comonomers. The PAMAM was then directly assembled to the surface of SPIONs by the ligand exchange reaction with SPIONs forming the MNPs-DOX. The hydrophilic PEG moieties provide the nanoparticles with colloidal stability and good-dispersity in aqueous solution. Comparing with the quick release of free DOX, the drug release behavior of MNPs-DOX exhibited a sustained drug release. Because the chemical cleavage of disulfide in the polymer backbone, a high cumulative drug release up to 60% in GSH within 48 h was observed, rather than only 26% in PBS (pH 7.4) without GSH. The MR imaging detection experiment showed that the MNPs-DOX had an enhanced T₂ relaxivity of 126 mM⁻¹ S⁻¹ for MR imaging. The results of the cytotoxicity assays showed a remarkable killing effect of cancer cells by MNPs-DOX due to the FA tumor-targeting ligand, comparing with non-targeted drug molecules. All the results showed that the as prepared multi-functional magnetic nanoparticles may serve as a promising theranostic candidate for targeted anticancer drug delivery and efficient detection through MR imaging in medical application.

Multi-functional magnetic nanoparticles for targeted anticancer drug delivery and efficient MR imaging detection in theranostics.

Synthesis of Distinct Iron Oxide Nanomaterial Shapes Using Lyotropic Liquid Crystal Solvents

A room temperature reduction-hydrolysis of Fe(III) precursors such as FeCl₃ or Fe(acac)₃ in various lyotropic liquid crystal phases (lamellar, hexagonal columnar, or micellar) formed by a range of ionic or neutral surfactants in H₂O is shown to be an effective and mild approach for the preparation of iron oxide (IO) nanomaterials with several morphologies (shapes and dimensions), such as extended thin nanosheets with lateral dimensions of several hundred nanometers as well as smaller nanoflakes and nanodiscs in the tens of nanometers size regime. We will discuss the role of the used surfactants and lyotropic liquid crystal phases as well as the shape and size differences depending upon when and how the resulting nanomaterials were isolated from the reaction mixture. The presented synthetic methodology using lyotropic liquid crystal solvents should be widely applicable to several other transition metal oxides for which the described reduction-hydrolysis reaction sequence is a suitable pathway to obtain nanoscale particles.

SPIONs/DOX loaded polymer nanoparticles for MRI detection and efficient cell targeting drug delivery

Reducible polydopamine coated magnetic nanoparticles (SPIONs@PDA) for both magnetic resonance imaging (MRI) detection and cell targeting drug delivery.