Magnetic micromotors crossing lipid membranes.

Nano/micromotors are self-propelled particles that show enhanced motion upon being triggered by a stimulus. Their use in nanomedicine has been widely explored, with special focus on imaging or drug delivery. However, a thorough understanding of the requirements for more efficient locomotion is still lacking.

Hybrid Macromolecular Constructs as a Platform for Spectral Nanoprobes for Advanced Cellular Barcoding in Flow Cytometry.

Herein, an advanced bioconjugation technique to synthesize hybrid polymer-antibody nanoprobes tailored for fluorescent cell barcoding in flow cytometry-based immunophenotyping of leukocytes is applied. A novel approach of attachment combining two fluorescent dyes on the copolymer precursor and its conjugation to antibody is employed to synthesize barcoded nanoprobes of antibody polymer dyes allowing up to six nanoprobes to be resolved in two-dimensional cytometry analysis. The major advantage of these nanoprobes is the construct design in which the selected antibody is labeled with an advanced copolymer bearing two types of fluorophores in different molar ratios.

Bloch points in nanostrips.

Complex magnetic materials hosting topologically non-trivial particle-like objects such as skyrmions are under intensive research and could fundamentally change the way we store and process data. One important class of materials are helimagnetic materials with Dzyaloshinskii-Moriya interaction. Recently, it was demonstrated that thin nanodisks consisting of two layers with opposite chirality can host a single stable Bloch point of two different types at the interface between the layers.

Nanoparticle-Induced Property Changes in Nematic Liquid Crystals.

Doping liquid crystals with nanoparticles is a widely accepted method to enhance liquid crystal's intrinsic properties. In this study, a quick and reliable method to characterise such colloidal suspensions using an optical multi-parameter analyser, a cross-polarised intensity measurement-based device, is presented. Suspensions characterised in this work are either plasmonic (azo-thiol gold AzoGNPs) or ferroelectric SnPS (SPS) nanoparticles in nematic liquid crystals.

Exploiting Unique Alignment of Cobalt Ferrite Nanoparticles, Mild Hyperthermia, and Controlled Intrinsic Cobalt Toxicity for Cancer Therapy.

Nanoparticle-based magnetic hyperthermia is a well-known thermal therapy platform studied to treat solid tumors, but its use for monotherapy is limited due to incomplete tumor eradication at hyperthermia temperature (45 °C). It is often combined with chemotherapy for obtaining a more effective therapeutic outcome. Cubic-shaped cobalt ferrite nanoparticles (Co-Fe NCs) serve as magnetic hyperthermia agents and as a cytotoxic agent due to the known cobalt ion toxicity, allowing the achievement of both heat and cytotoxic effects from a single platform.

Unveiling the Dynamical Assembly of Magnetic Nanocrystal Zig-Zag Chains via In Situ TEM Imaging in Liquid.

The controlled assembly of colloidal magnetic nanocrystals is key to many applications such as nanoelectronics, storage memory devices, and nanomedicine. Here, the motion and ordering of ferrimagnetic nanocubes in water via liquid-cell transmission electron microscopy is directly imaged in situ. Through the experimental analysis, combined with molecular dynamics simulations and theoretical considerations, it is shown that the presence of highly competitive interactions leads to the formation of stable monomers and dimers, acting as nuclei, followed by a dynamic growth of zig-zag chain-like assemblies.

Locomotion of Micromotors Due to Liposome Disintegration.

Synthetic micromotors are evaluated extensively in a range of biomedical, microscale transport, and environmental applications. Fundamental insight into micromotors that exhibit locomotion due to triggered disintegration of their associated liposomes is provided. Directed self-propulsion is observed when the lipid vesicles are solubilized using Triton X-100 (TX) and bile at sufficiently high concentrations.

An in vivo coil setup for AC magnetic field-mediated magnetic nanoparticle heating experiments.

In vitro and in vivo evaluation of magnetic nanoparticles in relation to magnetic fluid hyperthermia (MFH) treatment is an on-going quest. This current paper demonstrates the design, fabrication, and evaluation of an in vivo coil setup for real-time, whole body thermal imaging. Numerical calculations estimating the flux densities, and in silico analysis suggest that the proposed in vivo coil setup could be used for real-time thermal imaging during MFH experiments (within the limitations due to issues of penetration depth).

Microswimmers with Heat Delivery Capacity for 3D Cell Spheroid Penetration.

Micro- and nanoswimmers are a fast emerging concept that changes how colloidal and biological systems interact. They can support drug delivery vehicles, assist in crossing biological barriers, or improve diagnostics. We report microswimmers that employ collagen, a major extracellular matrix (ECM) constituent, as fuel and that have the ability to deliver heat incorporated magnetic nanoparticles when exposed to an alternating magnetic field (AMF).

Stable and manipulable Bloch point.

The prediction of magnetic skyrmions being used to change the way we store and process data has led to materials with Dzyaloshinskii-Moriya interaction coming into the focus of intensive research. So far, studies have looked mostly at magnetic systems composed of materials with single chirality. In a search for potential future spintronic devices, combination of materials with different chirality into a single system may represent an important new avenue for research.

Do Images of Biskyrmions Show Type-II Bubbles?

The intense research effort investigating magnetic skyrmions and their applications for spintronics has yielded reports of more exotic objects including the biskyrmion, which consists of a bound pair of counter-rotating vortices of magnetization. Biskyrmions have been identified only from transmission electron microscopy images and have not been observed by other techniques, nor seen in simulations carried out under realistic conditions. Here, quantitative Lorentz transmission electron microscopy, X-ray holography, and micromagnetic simulations are combined to search for biskyrmions in MnNiGa, a material in which they have been reported.

Disintegrating polymer multilayers to jump-start colloidal micromotors.

Colloidal systems with autonomous mobility are attractive alternatives to static particles for diverse applications. We present a complementary approach using pH-triggered disintegrating polymer multilayers for self-propulsion of swimmers. It is illustrated both experimentally and theoretically that homogenously coated swimmers exhibit higher velocity in comparison to their Janus-shaped counterparts.

Magnetic Interaction of Multifunctional Core-Shell Nanoparticles for Highly Effective Theranostics.

The controlled size and surface treatment of magnetic nanoparticles (NPs) make one-stage combination feasible for enhanced magnetic resonance imaging (MRI) contrast and effective hyperthermia. However, superparamagnetic behavior, essential for avoiding the aggregation of magnetic NPs, substantially limits their performance. Here, a superparamagnetic core-shell structure is developed, which promotes the formation of vortex-like intraparticle magnetization structures in the remanent state, leading to reduced dipolar interactions between two neighboring NPs, while during an MRI scan, the presence of a DC magnetic field induces the formation of NP chains, introducing increased local inhomogeneous dipole fields that enhance relaxivity.

Asymmetric Assembling of Iron Oxide Nanocubes for Improving Magnetic Hyperthermia Performance.

Magnetic hyperthermia (MH) based on magnetic nanoparticles (MNPs) is a promising adjuvant therapy for cancer treatment. Particle clustering leading to complex magnetic interactions affects the heat generated by MNPs during MH. The heat efficiencies, theoretically predicted, are still poorly understood because of a lack of control of the fabrication of such clusters with defined geometries and thus their functionality.

Thermal stability and topological protection of skyrmions in nanotracks.

Magnetic skyrmions are hailed as a potential technology for data storage and other data processing devices. However, their stability against thermal fluctuations is an open question that must be answered before skyrmion-based devices can be designed. In this work, we study paths in the energy landscape via which the transition between the skyrmion and the uniform state can occur in interfacial Dzyaloshinskii-Moriya finite-sized systems.

First order reversal curves and intrinsic parameter determination for magnetic materials; limitations of hysteron-based approaches in correlated systems.

The generic problem of extracting information on intrinsic particle properties from the whole class of interacting magnetic fine particle systems is a long standing and difficult inverse problem. As an example, the Switching Field Distribution (SFD) is an important quantity in the characterization of magnetic systems, and its determination in many technological applications, such as recording media, is especially challenging. Techniques such as the first order reversal curve (FORC) methods, were developed to extract the SFD from macroscopic measurements.

Ground state search, hysteretic behaviour, and reversal mechanism of skyrmionic textures in confined helimagnetic nanostructures.

Magnetic skyrmions have the potential to provide solutions for low-power, high-density data storage and processing. One of the major challenges in developing skyrmion-based devices is the skyrmions' magnetic stability in confined helimagnetic nanostructures. Through a systematic study of equilibrium states, using a full three-dimensional micromagnetic model including demagnetisation effects, we demonstrate that skyrmionic textures are the lowest energy states in helimagnetic thin film nanostructures at zero external magnetic field and in absence of magnetocrystalline anisotropy.

Enhanced oxidation of nanoparticles through strain-mediated ionic transport.

Geometry and confinement effects at the nanoscale can result in substantial modifications to a material's properties with significant consequences in terms of chemical reactivity, biocompatibility and toxicity. Although benefiting applications across a diverse array of environmental and technological settings, the long-term effects of these changes, for example in the reaction of metallic nanoparticles under atmospheric conditions, are not well understood. Here, we use the unprecedented resolution attainable with aberration-corrected scanning transmission electron microscopy to study the oxidation of cuboid Fe nanoparticles.

Tailoring the magnetic and pharmacokinetic properties of iron oxide magnetic particle imaging tracers.

Magnetic particle imaging (MPI) is an attractive new modality for imaging distributions of iron oxide nanoparticle tracers in vivo. With exceptional contrast, high sensitivity, and good spatial resolution, MPI shows promise for clinical imaging in angiography and oncology. Critically, MPI requires high-quality iron oxide nanoparticle tracers with tailored magnetic and surface properties to achieve its full potential.

Fine needle aspiration biopsy proves increased T-lymphocyte proliferation in tumor and decreased metastatic infiltration after treatment with doxorubicin bound to PHPMA copolymer carrier.

Introduction: Fine needle aspiration biopsy (FNAB) is an easy method with an option of repetitive withdrawal of cell material.

Methods: First, mice were inoculated with mouse T-lymphoma, after 10 d the samples from tumor, lymph nodes and spleen gained by FNAB and excision were analyzed by flow cytometry. Tumor progression was compared to the control group simultaneously.

Spectral analysis of doxorubicin accumulation and the indirect quantification of its DNA intercalation.

There is a wide range of techniques utilizing fluorescence of doxorubicin (Dox) commonly used for analysis of intracellular accumulation and destiny of various drug delivery systems containing this anthracycline antibiotic. Unfortunately, results of these studies can be significantly influenced by doxorubicin degradation product, 7,8-dehydro-9,10-desacetyldoxorubicinone (D*) forming spontaneously in aqueous environment, whose fluorescence strongly interfere with that of doxorubicin. Here, we define two microscopy techniques enabling to distinguish and separate Dox and D* emission based either on its spectral properties or on fluorescence lifetime analysis.

Doxorubicin attached to HPMA copolymer via amide bond modifies the glycosylation pattern of EL4 cells.

To avoid the side effects of the anti-cancer drug doxorubicin (Dox), we conjugated this drug to a N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer backbone. Dox was conjugated via an amide bond (Dox-HPMA(AM), PK1) or a hydrazone pH-sensitive bond (Dox-HPMA(HYD)). In contrast to Dox and Dox-HPMA(HYD), Dox-HPMA(AM) accumulates within the cell's intracellular membranes, including those of the Golgi complex and endoplasmic reticulum, both involved in protein glycosylation.

Establishment of imageable model of T-cell lymphoma growing in syngenic mice.

Background: Cancer research is focused on processes which influence in vivo tumor growth dynamics, tumor microenvironment and antitumor immune responses. Recently, it was documented that some cytostatics, including their polymeric derivatives, were able to trigger an anticancer immune response. Such interactions are studied mainly in vitro but relevant in vivo studies are necessary and were only recently started.

HPMA-copolymer conjugates targeted to tumor endothelium using synthetic oligopeptides.

Synthesis and characterization of N-(2-hydroxypropyl)methacrylamide (HPMA)-copolymer-based drug carriers targeted on specific receptors in the membrane of endothelial cells by oligopeptides (GRGDG, cyclo(RGDfK), and PHSCN) are described in this study. The copolymers containing targeting oligopeptides bound to the polymer via dodeca(ethylene glycol) spacer showed a receptor-specific time-dependent uptake with selected endothelial cell lines. The polymers were labeled with a fluorescent dye to enable monitoring of the interaction of the polymer conjugate with cells using fluorescence microscopy.

Biological evaluation of polymeric micelles with covalently bound doxorubicin.

The main limitation of contemporary anticancer chemotherapy remains to be the insufficient specificity of the drugs for tumor tissue, which decreases the maximum tolerated dose due to severe side effects. Micellar drug delivery systems based on amphiphilic block copolymers with a very narrow size distribution (10 to 100 nm in diameter) is a novel innovative approach. Here, we report biological and pharmacological properties of polymeric micellar conjugate containing doxorubicin (DOX) covalently bound via hydrolytically cleavable hydrazone bonds to the micelle core.