Magnetic Labeling Research Articles

Properties optimization analysis of amorphous ribbons in acoustic magnetic labels

Properties optimization analysis of amorphous ribbons in acoustic magnetic labels

Magnetophoretic Cell Sorting: Comparison of Different 3D-Printed Millifluidic Devices

Cell sorting is a highly applicable technology for multiple biological, biotechnological, and medical applications. Magnetic cell sorting can be realized with microfluidic and millifluidic flow cells. Additive manufacturing and 3D printing allow for fast prototyping and validating separation processes on this small scale. Therefore, our novel approach is to use this technology to print millifluidic channels and to directly evaluate them on their magnetic separation performance and their handling for cell manipulation. In this study, two different flow cells manufactured with a 3D printer are compared in regard to their use for the magnetic cell sorting of algae. One linear flow cell geometry and one spiraling flow cell geometry have been investigated with perpendicular magnetic fields. Iron oxide nanoparticles have been synthesized and characterized prior to their use as a magnetic label for algae cells. Particle uptake by algae are investigated by a phenanthroline assay, and the particle/algae mixtures are studied by microscopy, dynamic light scattering, zeta potential, and magnetophoretic mobility measurements. Depending on magnetic susceptibility, the cells undergo different magnetophoretic forces. Interestingly, the spiraling geometry leads to a better fractionation of algae cells in accordance with their iron oxide load.

Synthesis of Fe3O4 at different reaction temperatures and investigation of its magnetic properties on giant magnetoresistance (GMR) sensors for bio-detection applications

Magnetite (Fe3O4) nanoparticles with different reaction temperatures (TR= 40, 60 and 80°C) for the application of bio-detection have been successfully synthesized using the co-precipitation method. The average crystallite sizes of samples increased with the increase of TR and all samples showed high crystallinity with an inverse spinel cubic structure. The grain size increased with the increase of TR. On the other hand, all samples have polycrystalline structure and the brightest intensity at Miller's index (311). From the results of the vibrating sample magnetometer (VSM) analysis, it was found that there was an increase in magnetic properties such as Hc, Mr and Ms along with the increase reaction temperature. For example, the saturation magnetization increased with the increase of TR. Next, the giant magnetoresistance (GMR) biosensor was explored by using an exchange-biased GMR sensor with the Wheatstone bridge method to detect Fe3O4 with variations of reaction temperature in an alcohol solution of 50 μg/ml. A DC in-plane magnetic field was used for this measurement. It was found that the Vout curve is sensitive to the presence of Fe3O4 and the maximum Vout appears at 2.8 Oe by applying an external field to the sensor of ± 95 Oe. The Vout difference increased with the increase of reaction temperature, which can be attributed to higher saturation magnetization, causing more difficult fringing of the magnetic field. The relationship between TR and |ΔV| is ΔV = 0.0175x + 0.49, in which |ΔV| linearly increases with the increase of reaction temperature. This study demonstrates the feasibility of Fe3O4-based detection using a GMR sensor and Fe3O4 as magnetic labels will be useful for potential bio-detection applications.

Mechanistic insights into phenanthrene acropetal translocation via wheat xylem: Separation and identification of transfer proteins.

Polycyclic aromatic hydrocarbons (PAHs) have the potential to cause cancer, teratogenicity, and mutagenesis in humans. Long-term plant safe production relies on how PAHs are transported and coordinated across organs. However, the acropetal transfer mechanism of PAHs in staple crop stems, particularly in xylem, a critical path, is unknown. Herein, we first confirmed the presence of specific interaction between the proteins and phenanthrene by employing the magnetic phenanthrene-bound bead immunoassay and label free liquid chromatograph mass spectrometer (LC-MS/MS), suggesting that peroxidase (uniprot accession: A0A3B5XXD0) and unidentified proteins (uniprot accession: A0A3B6LUC6) may function as the carriers to load and acropetally translocate phenanthrene (a model PAH) in wheat xylem. This specified binding of protein-phenanthrene may form through hydrophobic interactions in the conservative binding region, as revealed by protein structural investigations and molecular docking. To further investigate the role of these proteins in phenanthrene solubilization, phenanthrene exposure was conducted: a substantial quantity of peroxidase was produced; an unusually high expression of uncharacterized proteins was observed, indicating their positive effects in the acropetal transfer of phenanthrene in wheat xylem. These data confirmed that the two proteins are crucial in the solubilization of phenanthrene in wheat xylem sap. Our findings provide fresh light on the molecular mechanism of PAH loading in plant xylem and techniques for ensuring the security of staple crops and improving the efficacy of phytoremediation in a PAH-contaminated environment.

GMR Biosensor Based on Spin-Valve Thin Films for Green-Synthesized Magnetite (Fe<sub>3</sub>O<sub>4</sub>) Nanoparticles Label Detection

The giant magnetoresistance (GMR) thin film with spin valve (SV) structure of Ta (2 nm)/Ir20Mn80(10 nm)/Co90Fe10(3 nm)/Cu (2.2 nm)/Co84Fe10B4(10 nm)/Ta (5 nm)] fabricated by RF magnetron sputtering method with a magnetoresistance (MR) of 6% was used in this work. Green synthesis of Fe3O4 magnetic nanoparticles (MNPs) using Moringa Oleifera (MO) leaf extract have been successfully conducted using the coprecipitation method. Fe3O4 MNPs demonstrated the inverse cubic spinel structure with the average crystallite size of 13.8 nm and decreased to 11.8 nm for Fe3O4/PEG. Fe3O4, as a magnetic label, integrated with a Wheatstone bridge-GMR sensor provides access to GMR-based biosensors. The induced-field increase leads the signal (ΔV) to increase with increasing nanoparticle concentration. It was discovered that a sensor can distinguish different types of magnetic labels. The sensitivity for Fe3O4 and MO-green synthesized Fe3O4 magnetic label was 0.04 and 0.1 mV/g/L, respectively. The GMR sensor performed the highest sensitivity on the MO-green synthesized Fe3O4 label. Thus, the SV thin film as a sensor and the green-synthesized Fe3O4 nanoparticles as a superior magnetic label are an excellent combination for biosensor application.

Remote Magnetic Microengineering and Alignment of Spheroids into 3D Cellular Fibers

AbstractDeveloping in vitro models that recapitulate the in vivo organization of living cells in a 3D microenvironment is one of the current challenges in the field of tissue engineering. In particular for anisotropic tissues where alignment of precursor cells is required for them to create functional structures. Herein, a new method is proposed that allows aligning in the direction of a uniform magnetic field both individual cells (muscle, stromal, and stem cells) or spheroids in a thermoresponsive collagen hydrogel. In an all‐in‐one approach, spheroids are generated at high throughput by magnetic engineering using microfabricated micromagnets and are used as building blocks to create 3D anisotropic tissue structures of different scales. The magnetic cells and spheroids alignment process is optimized in terms of magnetic cell labeling, concentration, and size. Anisotropic structures are induced to form fibers in the direction of the magnetic alignment, with the respective roles of the magnetic field, the mechanical stretching of hydrogel or co‐culture of the aligned cells with non‐magnetic stromal cells, being investigated. Over days, spheroids fuse into 3D tubular structures, oriented in the direction of the magnetic alignment. Moreover, in the case of the muscle cells model, multinucleated cells can be observed within the fibers.

In Vivo Cellular Magnetic Imaging: Labeled vs. Unlabeled Cells.

Superparamagnetic iron oxide (SPIO)-labeling of cells has been applied for magnetic resonance imaging (MRI) cell tracking for over 30 years, having resulted in a dozen or so clinical trials. SPIO nanoparticles are biodegradable and can be broken down into elemental iron, and hence the tolerance of cells to magnetic labeling has been overall high. Over the years, however, single reports have accumulated demonstrating that the proliferation, migration, adhesion and differentiation of magnetically labeled cells may differ from unlabeled cells, with inhibition of chondrocytic differentiation of labeled human mesenchymal stem cells (hMSCs) as a notable example. This historical perspective provides an overview of some of the drawbacks that can be encountered with magnetic labeling. Now that magnetic particle imaging (MPI) cell tracking is emerging as a new in vivo cellular imaging modality, there has been a renaissance in the formulation of SPIO nanoparticles this time optimized for MPI. Lessons learned from the occasional past pitfalls encountered with SPIO-labeling of cells for MRI may expedite possible future clinical translation of (combined) MRI/MPI cell tracking.

Noninvasive functional lung imaging with hyperpolarized xenon

HintergrundDie Magnetresonanztomographie (MRT) ist ein nichtinvasives Verfahren mit hervorragendem Weichteilkontrast. Aufgrund der geringen Protonendichte und vielen Luft-Gewebe-Übergängen ist die Anwendung in der Lunge jedoch eingeschränkt, so dass hier häufig röntgenbasierte Methoden eingesetzt werden (mit den bekannten Nachteilen ionisierender Strahlung).FragestellungIn dieser Übersichtsarbeit wird die Lungen-MRT mit hyperpolarisiertem Xenon-129 (Xe-MRT) dargestellt. Die Xe-MRT erlaubt einzigartige wertvolle Einblicke in die Mikrostruktur und Funktion der Lunge, einschließlich des Gasaustauschs mit roten Blutkörperchen – Parameter, die mit klinischen Standardmethoden nicht zugänglich sind.Material und MethodenDurch die magnetische Markierung, die Hyperpolarisierung, wird das Signal von Xenon-129 um bis zu 100.000-fach verstärkt. Hierbei werden die Elektronen von Rubidium mittels Laserlicht zunächst auf 100 % polarisiert und dann durch Stöße auf Xenon übertragen. Danach wird das hyperpolarisierte Gas in einem Beutel zum Patienten gebracht und eingeatmet, kurz bevor die MRT-Aufnahmen beginnen.ErgebnisseDurch spezielle Programmierungen (Sequenzen) in der MRT kann die Ventilation, Mikrostruktur oder der Gasaustausch der Lunge in 3‑D dargestellt werden. Dies ermöglicht z. B. die quantitative Darstellung von Belüftungsdefekten, der Größe der Alveolen, der Gasaufnahme im Gewebe und des Gastransfers ins Blut.SchlussfolgerungDie Xe-MRT liefert einzigartige Informationen über den Zustand der Lunge – nichtinvasiv, in vivo und in weniger als einer Minute.

Widespread cell stress and mitochondrial dysfunction occur in patients with early Alzheimer's disease.

Cell stress and impaired oxidative phosphorylation are central to mechanisms of synaptic loss and neurodegeneration in the cellular pathology of Alzheimer's disease (AD). In this study, we quantified the in vivo expression of the endoplasmic reticulum stress marker, sigma 1 receptor (S1R), using [11C]SA4503 positron emission tomography (PET), the mitochondrial complex I (MC1) with [18F]BCPP-EF, and the presynaptic vesicular protein SV2A with [11C]UCB-J in 12 patients with early AD and in 16 cognitively normal controls. We integrated these molecular measures with assessments of regional brain volumes and cerebral blood flow (CBF) measured with magnetic resonance imaging arterial spin labeling. Eight patients with AD were followed longitudinally to estimate the rate of change of the physiological and structural pathology markers with disease progression. The patients showed widespread increases in S1R (≤ 27%) and regional reduction in MC1 (≥ -28%) and SV2A (≥ -25%) radioligand binding, brain volume (≥ -23%), and CBF (≥ -26%). [18F]BCPP-EF PET MC1 binding (≥ -12%) and brain volumes (≥ -5%) showed progressive reductions over 12 to 18 months, suggesting that they both could be used as pharmacodynamic indicators in early-stage therapeutics trials. Associations of reduced MC1 and SV2A and increased S1R radioligand binding with reduced cognitive performance in AD, although exploratory, suggested a loss of metabolic functional reserve with disease. Our study thus provides in vivo evidence for widespread, clinically relevant cellular stress and bioenergetic abnormalities in early AD.

Public Cord Blood Banks as a source of starting material for clinical grade HLA-homozygous induced pluripotent stem cells

BackgroundThe increasing number of clinical trials for induced pluripotent stem cell (iPSC)-derived cell therapy products makes the production on clinical grade iPSC more and more relevant and necessary. Cord blood banks are an ideal source of young, HLA-typed and virus screened starting material to produce HLA-homozygous iPSC lines for wide immune-compatibility allogenic cell therapy approaches. The production of such clinical grade iPSC lines (haplolines) involves particular attention to all steps since donor informed consent, cell procurement and a GMP-compliant cell isolation process.MethodsHomozygous cord blood units were identified and quality verified before recontacting donors for informed consent. CD34+ cells were purified from the mononuclear fraction isolated in a cell processor, by magnetic microbeads labelling and separation columns.ResultsWe obtained a median recovery of 20.0% of the collected pre-freezing CD34+, with a final product median viability of 99.1% and median purity of 83.5% of the post-thawed purified CD34+ population.ConclusionsHere we describe our own experience, from unit selection and donor reconsenting, in generating a CD34+ cell product as a starting material to produce HLA-homozygous iPSC following a cost-effective and clinical grade-compliant procedure. These CD34+ cells are the basis for the Spanish bank of haplolines envisioned to serve as a source of cell products for clinical research and therapy.

Detection of green-synthesized magnetite nanoparticles using spin-valve GMR-based sensor and their potential as magnetic labels

Exploration of magnetic nanoparticle labels for giant magnetoresistance (GMR) biosensing technology is crucial because their characteristics determine GMR-based sensor performance, related to their stray field and compatibility to biomolecule. We investigated the potency of the green-synthesized magnetite (Fe3O4) nanoparticle as a green-magnetic label on a spin-valve (SV) GMR sensor based on a [Ta (2 nm)/Ir20Mn80 (10 nm)/Co90Fe10 (3 nm)/Cu (2.2 nm)/(Co84Fe10B4 (10 nm)/Ta (5 nm)] structure that generated a 7.3 Oe exchange-bias field and 5.73% magnetoresistance. Fe3O4 nanoparticles were synthesized by a chemical coprecipitation method utilizing Moringa oleifera (MO) leaf extract as a natural reducing agent. The green-synthesized Fe3O4 nanoparticles exhibited a cubic inverse spinel structure as a pristine Fe3O4 characteristic. The crystallite size of green-synthesized Fe3O4 was larger than that of Fe3O4, reaching ∼ 14 nm, and formed a particle size of 29.1 nm. Its magnetic properties included soft ferromagnetic behavior with 55.5 emu/g saturation magnetization and 54 Oe coercivity; its saturation was lower than that of Fe3O4 due to the presence of the phytochemical compound of MO extract. In addition, to observe its potency as a magnetic label for biosensing, conventionally synthesized nanoparticles, surface modification using polyethylene glycol (PEG), and attachment of an α-amylase enzyme as a biomarker sample on green nanoparticle labels were also investigated. When measuring various concentration labels using the SV-GMR thin film, the green-synthesized Fe3O4 achieved a linear relationship and a better sensitivity of 0.098 mV/mg/mL than that of the conventional compound. The sensor could detect Fe3O4-labelled α-amylase enzyme as indicated by the decreasing output voltage, a consequence of altering the surface conditions of the nanoparticles. Therefore, green-synthesized nanoparticles are reliable and achieve competitive performance as magnetic labels in GMR sensors.

Altered Coupling Between Cerebral Blood Flow and Voxel-Mirrored Homotopic Connectivity Affects Stroke-Induced Speech Comprehension Deficits.

The neurophysiological basis of the association between interhemispheric connectivity and speech comprehension processing remains unclear. This prospective study examined regional cerebral blood flow (CBF), homotopic functional connectivity, and neurovascular coupling, and their effects on comprehension performance in post-stroke aphasia. Multimodal imaging data (including data from functional magnetic resonance imaging and arterial spin labeling imaging) of 19 patients with post-stroke aphasia and 22 healthy volunteers were collected. CBF, voxel-mirrored homotopic connectivity (VMHC), CBF-VMHC correlation, and CBF/VMHC ratio maps were calculated. Between-group comparisons were performed to identify neurovascular changes, and correlation analyses were conducted to examine their relationship with the comprehension domain. The correlation between CBF and VMHC of the global gray matter decreased in patients with post-stroke aphasia. The total speech comprehension score was significantly associated with VMHC in the peri-Wernicke area [posterior superior temporal sulcus (pSTS): r = 0.748, p = 0.001; rostroventral area 39: r = 0.641, p = 0.008]. The decreased CBF/VMHC ratio was also mainly associated with the peri-Wernicke temporoparietal areas. Additionally, a negative relationship between the mean CBF/VMHC ratio of the cingulate gyrus subregion and sentence-level comprehension was observed (r = −0.658, p = 0.006). These findings indicate the contribution of peri-Wernicke homotopic functional connectivity to speech comprehension and reveal that abnormal neurovascular coupling of the cingulate gyrus subregion may underly comprehension deficits in patients with post-stroke aphasia.

Three-dimensional arterial spin labeling and diffusion kurtosis imaging in evaluating perfusion and infarct area size in acute cerebral ischemia.

BACKGROUNDEarly thrombolytic therapy is crucial to treat acute cerebral infarction, especially since the onset of thrombolytic therapy takes 1-6 h. Therefore, early diagnosis and evaluation of cerebral infarction is important.AIMTo investigate the diagnostic value of magnetic resonance multi-delay three-dimensional arterial spin labeling (3DASL) and diffusion kurtosis imaging (DKI) in evaluating the perfusion and infarct area size in patients with acute cerebral ischemia.METHODSEighty-four patients who experienced acute cerebral ischemia from March 2019 to February 2021 were included. All patients in the acute stage underwent magnetic resonance-based examination, and the data were processed by the system’s own software. The apparent diffusion coefficient (ADC), average diffusion coefficient (MD), axial diffusion (AD), radial diffusion (RD), average kurtosis (MK), radial kurtosis (fairly RK), axial kurtosis (AK), and perfusion parameters post-labeling delays (PLD) in the focal area and its corresponding area were compared. The correlation between the lesion area of cerebral infarction under MK and MD and T2-weighted imaging (T2WI) was analyzed.RESULTSThe DKI parameters of focal and control areas in the study subjects were compared. The ADC, MD, AD, and RD values in the lesion area were significantly lower than those in the control area. The MK, RK, and AK values in the lesion area were significantly higher than those in the control area. The MK/MD value in the infarct lesions was used to determine the matching situation. MK/MD < 5 mm was considered matching and MK/MD ≥ 5 mm was considered mismatching. PLD1.5s and PLD2.5s perfusion parameters in the central, peripheral, and control areas of the infarct lesions in MK/MD-matched and -unmatched patients were not significantly different. PLD1.5s and PLD2.5s perfusion parameter values in the central area of the infarct lesions in MK/MD-matched and -unmatched patients were significantly lower than those in peripheral and control areas. The MK and MD maps showed a lesion area of 20.08 ± 5.74 cm2 and 22.09 ± 5.58 cm2, respectively. T2WI showed a lesion area of 19.76 ± 5.02 cm2. There were no significant differences in the cerebral infarction lesion areas measured using the three methods. MK, MD, and T2WI showed a good correlation.CONCLUSIONDKI parameters showed significant difference between the focal and control areas in patients with acute ischemic cerebral infarction. 3DASL can effectively determine the changes in perfusion levels in the lesion area. There was a high correlation between the area of the infarct lesions diagnosed by DKI and T2WI.

A magnetic nanoparticle assisted microfluidic system for low abundance cell sorting with high recovery

Low abundance cell sorting has fundamental applications in cell research and therapy, such as cancer diagnosis, cell transplantation, and immunology. However, various methods for isolating low abundance cells are challenging due to the low cell recovery rate and throughput. In this paper, we propose a magnetic nanoparticle assisted microfluidic system (MNPAMS) for selecting low abundance cells with high cell recovery rate. This system integrates an active magnetic nanoparticles (MNPs)-based sorting mechanism and a passive size-based capture mechanism into one microfluidic chip. Polydimethylsiloxane (PDMS) was used to fabricate a bilayer microfluidic chip. The magnetic and fluid field models of the MNPAMS were analyzed using finite element method (FEM). Furthermore, the sorting performance was validated by mixed HeLa cell samples of three different concentrations. The experimental results show the target cells were concentrated in the arrays of structures 2 and structures 3. For different concentrations, the target cell recovery rate is relatively stable up to maximum 99.5%. Besides, the recovery efficiency of low abundance cells sorting can reach 88.6% for a 1/100 of the original sample concentration. Based on these results, the MNPAMS has the potential to facilitate liquid biopsy and fundamental biomedical studies with high target cells recovery. • A Magnetic Nanoparticle Assist Microfluidic System was proposed for cell sorting. • The system combined magnetic labeling with microstructures capturing mechanism. • The highest recovery efficiency could reach 88.6% for low abundance cell sorting.

Nanoparticle Amplification Labeling for High-Performance Magnetic Cell Sorting.

Magnetic cell sorting is an enabling tool for the isolation of specific cellular subpopulations for downstream applications and requires the cells to be labeled by a sufficient number of magnetic nanoparticles to leverage magnetophoresis for efficient separation. This requirement makes it challenging to target weakly expressed biomarkers. Here, we developed a new approach that selectively and efficiently amplifies the magnetic labeling on cells through sequentially connected antibodies and nanoparticles delivered to the surface or interior of the cell. Using this approach, we achieved amplification up to 100-fold for surface and intracellular markers. We also demonstrated the utility of this assay for enabling high-performance magnetic cell sorting when it is applied to the analysis of rare tumor cells for cancer diagnosis and the purification of transfected CAR T cells for immunotherapy. The data presented demonstrate a useful tool for the stratification of rare cell subpopulations.

A magnetoimpedance biosensor microfluidic platform for detection of glial fibrillary acidic protein in blood for acute stroke classification

Acute stroke is the third leading cause of mortality and disability worldwide. Administration of appropriate therapy for acute stroke is critically dependent on timely classification into either ischemic or hemorrhagic subtypes, which have divergent treatment pathways. The current classification method is based on neuroimaging, which generally requires the transport of the patient to a hospital-based facility unless a mobile stroke unit is available. Plasma glial fibrillary acidic protein (GFAP) level has been identified as a useful blood-based biomarker to differentiate stroke subtypes. However, its conventional immunoassay methods are laboratory-based and time-consuming. Novel approaches for rapid stroke classification near the patients are urgently needed. Here, we report the development and testing of a microfluidic-based magnetoimpedance biosensor platform for measuring GFAP levels. The platform consists of a microfluidic chip for GFAP extraction from a blood sample and a magnetoimpedance (MI) biosensor that employs Dynabeads as a magnetic label to capture the GFAP molecules. We demonstrated the detection of recombinant GFAP protein in phosphate-buffered saline (PBS) and in mouse blood samples (detection limit 0.01 ng/mL) and of physiological GFAP in blood and plasma samples (detection limit 1.0 ng/mL) obtained from acute stroke patients. This detection level is within the range of cut-off levels required for clinical stroke subtype differentiation. This platform has the potential to be incorporated into a small device with further development to assist in the classification of acute stroke patients and clinical decision-making at the point-of-care.

Extracellular magnetic labeling of biomimetic hydrogel-induced human mesenchymal stem cell spheroids with ferumoxytol for MRI tracking.

Labeling of mesenchymal stem cells (MSCs) with superparamagnetic iron oxide nanoparticles (SPIONs) has emerged as a potential method for magnetic resonance imaging (MRI) tracking of transplanted cells in tissue repair studies and clinical trials. Labeling of MSCs using clinically approved SPIONs (ferumoxytol) requires the use of transfection reagents or magnetic field, which largely limits their clinical application. To overcome this obstacle, we established a novel and highly effective method for magnetic labeling of MSC spheroids using ferumoxytol. Unlike conventional methods, ferumoxytol labeling was done in the formation of a mechanically tunable biomimetic hydrogel-induced MSC spheroids. Moreover, the labeled MSC spheroids exhibited strong MRI T2 signals and good biosafety. Strikingly, the encapsulated ferumoxytol was localized in the extracellular matrix (ECM) of the spheroids instead of the cytoplasm, minimizing the cytotoxicity of ferumoxytol and maintaining the viability and stemness properties of biomimetic hydrogel-induced MSC spheroids. This demonstrates the potential of this method for post-transplantation MRI tracking in the clinic.

α1B‐Adrenoceptor is Required for Chemokine (C‐X‐C Motif) Receptor 4 Mediated Chemotaxis in THP1 Cells

IntroductionChemokine (C‐X‐C motif) receptor 4 (CXCR4) is a key regulator of leukocyte trafficking under physiological conditions and in numerous inflammatory disease processes. Previously, we demonstrated that CXCR4 hetero‐oligomerizes with α1B‐adrenoceptors (ARs), through which the receptors cross‐talk. The existence and function of these hetero‐oligomers in leukocytes, however, is unknown. Thus, we tested whether such heteromeric complexes are detectable in the human monocytic cell line THP1 and in freshly isolated human monocytes, and evaluated how α1B‐AR knockdown by CRISPR/Cas9 gene editing in THP1 cells affects CXCR4‐mediated chemotaxis.MethodsPeripheral blood mononuclear cells were isolated by density gradient centrifugation from human whole blood; monocytes were then isolated via negative selection using MACS LS, an indirect magnetic labeling system. Proximity ligation assays (PLA) were used to visualize individual receptors and receptor‐receptor interactions in THP1 cells and freshly isolated monocytes. CRISPR/Cas9 gene editing was utilized to create a α1B‐AR knockout strain (ADRA1BKO); wild type THP1 cells were used as a negative control (ADRA1Bwt). Cell migration toward the cognate CXCR4 agonist chemokine (C‐X‐C motif) ligand 12 (CXCL12) was tested employing a 96 well Boyden chamber. Transmigrated cells were counted automatically utilizing high contrast bright field and post‐imaging particle analyses. The chemotactic index (ChI) was calculated as the ratio of cells that transmigrated in the presence versus the absence of CXCL12. Data were analyzed with ANOVA/Tukey’s post‐hoc. Data are mean ± SE from n=4 experiments performed on different days. A 2‐tailed p&lt;0.05 was considered significant.ResultsPLA confirmed the presence of endogenously and constitutively expressed CXCR4:α1B‐AR heteromers in freshly isolated monocytes and THP1 cells. PLA signals for α1B‐AR and CXCR4:α1B‐AR heteromers were not detectable in ADRA1BKO cells. CXCR4 signals were not affected by CRISPR/Cas9 gene knockout. ADRA1Bwtcells showed a bell‐shaped chemotactic dose response to CXCL12 with a maximal ChI of 9.1±1.1 at 100 nM. CRISPR/Cas9 knockout of α1B‐AR reduced the chemotactic response to CXCL12 by 89±52% (p&lt;0.05). ADRA1BKO results were replicated in an additional α1B‐AR knockout strain to rule out clonal effects.ConclusionOur observations suggest that CXCR4 heteromerizes with α1B‐AR in human monocytes and that CXCL12‐mediated chemotaxis depends on the formation of CXCR4:α1B‐AR heteromers. These data provide evidence for a novel molecular mechanism by which CXCR4‐mediated chemotaxis in monocytes/leukocytes is controlled.

Lipophilic Magnetic Photonic Nanochains for Practical Anticounterfeiting.

Magnetic photonic crystals (PCs) possess attractive magnetic orientation, flexible pattern designability, and abundant angle-dependent colors, providing immense potential in anticounterfeiting field. However, all-solid magnetic PCs-based labels generally suffer from incompatibility with screen printing techniques, and inferior environmental endurance and mechanical properties. Herein, by developing a selective concentration polymerization method under magnetic field (H) in microheterogenous dimethyl sulfoxide-water binary solvents, individual tens-of-micrometer-length lipophilic magnetic photonic nanochains (PNCs) of full-width at half-maxima below 30nm are fabricated, which, after simply dispersed in solvent-free cycloaliphatic epoxy resin, can be formulated as photonic inks to print robust anticounterfeiting labels through an H-assisted screen-printing technology. The as-printed labels possess vivid optically variable effects (OVEs) associated with the spatial distribution of H directionality, which are easy to identify by the naked eye but difficult to imitate and duplicate, while they show excellent environmental resistance and mechanical properties, promising practical applications in banknotes and high-grade commodities. The polymerization mechanism of the lipophilic PNCs is elucidated, and the OVEs are deciphered in numerical simulation. Besides an efficient way to build organic-inorganic hybrid nanostructures, the work provides advanced structural color pigments to achieve the practical application of magnetic PCs in such an anticounterfeiting field.

Noninvasive functional lung imaging with hyperpolarized xenon : Breakthrough for diagnostics?

HintergrundDie Magnetresonanztomographie (MRT) ist ein nichtinvasives Verfahren mit hervorragendem Weichteilkontrast. Aufgrund der geringen Protonendichte und vielen Luft-Gewebe-Übergängen ist die Anwendung in der Lunge jedoch eingeschränkt, so dass hier häufig röntgenbasierte Methoden eingesetzt werden (mit den bekannten Nachteilen ionisierender Strahlung).FragestellungIn dieser Übersichtsarbeit wird die Lungen-MRT mit hyperpolarisiertem Xenon-129 (Xe-MRT) dargestellt. Die Xe-MRT erlaubt einzigartige wertvolle Einblicke in die Mikrostruktur und Funktion der Lunge, einschließlich des Gasaustauschs mit roten Blutkörperchen – Parameter, die mit klinischen Standardmethoden nicht zugänglich sind.Material und MethodenDurch die magnetische Markierung, die Hyperpolarisierung, wird das Signal von Xenon-129 um bis zu 100.000-fach verstärkt. Hierbei werden die Elektronen von Rubidium mittels Laserlicht zunächst auf 100 % polarisiert und dann durch Stöße auf Xenon übertragen. Danach wird das hyperpolarisierte Gas in einem Beutel zum Patienten gebracht und eingeatmet, kurz bevor die MRT-Aufnahmen beginnen.ErgebnisseDurch spezielle Programmierungen (Sequenzen) in der MRT kann die Ventilation, Mikrostruktur oder der Gasaustausch der Lunge in 3‑D dargestellt werden. Dies ermöglicht z. B. die quantitative Darstellung von Belüftungsdefekten, der Größe der Alveolen, der Gasaufnahme im Gewebe und des Gastransfers ins Blut.SchlussfolgerungDie Xe-MRT liefert einzigartige Informationen über den Zustand der Lunge – nichtinvasiv, in vivo und in weniger als einer Minute.