Magnetic Labeling Research Articles

Soil microbial metabolism on carbon and nitrogen transformation links the crop-residue contribution to soil organic carbon

The beneficial effect of crop residue amendment on soil organic carbon (SOC) stock and stability depends on the functional response of soil microbial communities. Here we synchronized microbial metagenomic analysis, nuclear magnetic resonance and plant-15N labeling technologies to gain understanding of how microbial metabolic processes affect SOC accumulation in responses to differences in N supply from residues. Residue amendment brought increases in the assemblage of genes involved in C-degradation profiles from labile to recalcitrant C compounds as well as N mineralization. The N mineralization genes were correlated with the C and N accumulation in the particulate and mineral-associated C pools, and plant-derived aliphatic forms of SOC. Thus, the combined C and N metabolic potential of the microbial community transforms residue into persistent organic compounds, thereby increasing C and N sequestration in stable SOC pools. This study emphasizes potential microbially mediated mechanisms by which residue N affects C sequestration in soils.

Simultaneous Hemodynamic and Structural Imaging of Ischemic Stroke With Magnetic Resonance Fingerprinting Arterial Spin Labeling.

Perfusion and structural imaging play an important role in ischemic stroke. Magnetic resonance fingerprinting (MRF) arterial spin labeling (ASL) is a novel noninvasive method of ASL perfusion that allows simultaneous estimation of cerebral blood flow (CBF), bolus arrival time (BAT), and tissue T1 map in a single scan of <4 minutes. Here, we evaluated the utility of MRF-ASL in patients with ischemic stroke in terms of detecting hemodynamic and structural damage and predicting neurological deficits and disability. A total of 34 patients were scanned on 3T magnetic resonance imaging. MRF-ASL, standard single-delay pseudo-continuous ASL, T2-weighted, and diffusion magnetic resonance imaging were performed. Regions of interest of lesion and contralateral normal tissues were manually delineated. CBF (with 2 different compartmental models), BAT, and tissue T1 parameters were quantified. Cross-sectional linear regression analyses were performed to examine the relationship between MRF-ASL parameters and National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale. Receiver operating characteristic analyses were performed to determine the utility of MRF-ASL in the classification of stroke lesion voxels. MRF-ASL derived parameters revealed a significant difference between stroke lesion and contralateral normal regions of interest, in that lesion regions manifested a lower CBF1-compartment (P<0.001), lower CBF2-compartment (P<0.001), longer BAT (P=0.002), and longer T1 (P<0.001) compared with normal regions of interest. NIHSS scores at acute stage revealed a strong association with lesion-normal differences in CBF1-compartment,diff (β=-0.11, P=0.008), CBF2-compartment,diff (β=-0.16, P=0.003), and T1,diff (β=0.008, P=0.001). MRF-ASL parameters were also predictive of NIHSS score and modified Rankin Scale scale measured at a later stage, although the degree of the associations was weaker. These associations tended to be even stronger when the MRF-ASL data were acquired at the acute/subacute stage. Compared with standard pseudo-continuous ASL, the multiparametric capability of MRF-ASL yielded higher area under curve values in the receiver operating characteristic analyses of stroke voxel classifications. MRF-ASL may provide a new approach for quantitative hemodynamic and structural imaging in ischemic stroke.

Preparation of layering-structured magnetic fluorescent liposomes and labeling of HepG2 cells.

At present, surgical resection and chemotherapy are still the main treatments for hepatocellular carcinoma and other cancers, but the curative effect and survival rate are not ideal. In this study, we aim to prepare a carrier with low toxicity, high biocompatibility and targeted transport for the treatment of hepatocellular carcinoma. CdSe quantum dots (QDs) modified with oleic acid were synthesized. Then hydrophobic CdSe QDs and hydrophilic super-paramagnetic Fe3O4 particles were encapsulated into different layers of liposomes to form magnetic fluorescent liposomes (MFLs). MFLs in the aqueous would quickly drift towards the external magnet and the entire process was clearly observed with fluorescence microscope. The fluorescence spectra revealed that the fluorescence properties of MFLs were similar to that of CdSe QDs. QDs had an average size of 3.32 nm with good fluorescence properties. The size of MFLs was about 100 nm (transmission electron microscopy (TEM) analysis showed the average size of MFLs was about 82.8 nm and dynamic light scattering (DLS) detection showed 111.9 nm). After being cultured with MFLs for 8 h, HepG2 cells were labeled by MFLs, and good fluorescence images were obtained. MTT analysis also expressed their good biocompatibility. The prepared MFLs had multi-function and could be used as ideal drug carriers.

Microelectromechanical Systems Based on Magnetic Polymer Films

Microelectromechanical systems (MEMS) have been increasingly used worldwide in a wide range of applications, including high tech, energy, medicine or environmental applications. Magnetic polymer composite films have been used extensively in the development of the micropumps and valves, which are critical components of the microelectromechanical systems. Based on the literature survey, several polymers and magnetic micro and nanopowders can be identified and, depending on their nature, ratio, processing route and the design of the device, their performances can be tuned from simple valves and pumps to biomimetic devices, such as, for instance, hearth ventricles. In many such devices, polymer magnetic films are used, the disposal of the magnetic component being either embedded into the polymer or coated on the polymer. One or more actuation zones can be used and the flow rate can be mono-directional or bi-directional depending on the design. In this paper, we review the main advances in the development of these magnetic polymer films and derived MEMS: microvalve, micropump, micromixer, microsensor, drug delivery micro-systems, magnetic labeling and separation microsystems, etc. It is important to mention that these MEMS are continuously improving from the point of view of performances, energy consumption and actuation mechanism and a clear tendency in developing personalized treatment. Due to the improved energy efficiency of special materials, wearable devices are developed and be suitable for medical applications.

Combining residual attention mechanisms and generative adversarial networks for hippocampus segmentation

This research discussed a deep learning method based on an improved generative adversarial network to segment the hippocampus. Different convolutional configurations were proposed to capture information obtained by a segmentation network. In addition, a generative adversarial network based on Pixel2Pixel was proposed. The generator was a codec structure combining a residual network and an attention mechanism to capture detailed information. The discriminator used a convolutional neural network to discriminate the segmentation results of the generated model and that of the expert. Through the continuously transmitted losses of the generator and discriminator, the generator reached the optimal state of hippocampus segmentation. T1-weighted magnetic resonance imaging scans and related hippocampus labels of 130 healthy subjects from the Alzheimer's disease Neuroimaging Initiative dataset were used as training and test data; similarity coefficient, sensitivity, and positive predictive value were used as evaluation indicators. Results showed that the network model could achieve an efficient automatic segmentation of the hippocampus and thus has practical relevance for the correct diagnosis of diseases, such as Alzheimer's disease.

A pump-free microfluidic device for fast magnetic labeling of ischemic stroke biomarkers.

This research proposes a low-cost and simple operation microfluidic chip to enhance the magnetic labeling efficiency of two ischemic stroke biomarkers: cellular fibronectin (c-Fn) and matrix metallopeptidase 9 (MMP9). This fully portable and pump-free microfluidic chip is operated based on capillary attractions without any external power source and battery. It uses an integrated cellulose sponge to absorb the samples. At the same time, a magnetic field is aligned to hold the target labeled by the magnetic nanoparticles (MNPs) in the pre-concentrated chamber. By using this approach, the specific targets are labeled from the beginning of the sampling process without preliminary sample purification. The proposed study enhanced the labeling efficiency from 1h to 15min. The dynamic interactions occur in the serpentine channel, while the crescent formation of MNPs in the pre-concentrated chamber, acting as a magnetic filter, improves the biomarker-MNP interaction. The labeling optimization by the proposed device influences the dynamic range by optimizing the MNP ratio to fit the linear range across the clinical cutoff value. The limits of detection (LODs) of 2.8ng/mL and 54.6ng/mL of c-Fn measurement were achieved for undiluted and four times dilutions of MNP, respectively. While for MMP9, the LODs were 11.5ng/mL for undiluted functionalized MNP and 132ng/mL for four times dilutions of functionalized MNP. The results highlight the potential use of this device for clinical sample preparation and specific magnetic target labeling. When combined with a detection system, it could also be used as an integrated component of a point-of-care platform.

Detection of impaired renal allograft function in paediatric and young adult patients using arterial spin labelling MRI (ASL-MRI)

The study aimed to discriminate renal allografts with impaired function by measuring cortical renal blood flow (cRBF) using magnetic resonance imaging arterial spin labelling (ASL-MRI) in paediatric and young adult patients. We included 18 subjects and performed ASL-MRI on 1.5 T MRI to calculate cRBF on parameter maps. cRBF was correlated to calculated glomerular filtration rate (GFR) and compared between patient groups with good (GFR ≥ 60 mL/min/1.73 m2) and impaired allograft function (GFR < 60 mL/min/1.73 m2). Mean cRBF in patients with good allograft function was significantly higher than in patients with impaired allograft function (219.89 ± 57.24 mL/min/100 g vs. 146.22 ± 41.84 mL/min/100 g, p < 0.008), showing a highly significant correlation with GFR in all subjects (r = 0.75, p < 0.0001). Also, the diffusion-weighted imaging (DWI-MRI) apparent diffusion coefficient (ADC) and Doppler measurements of peak-systolic and end-diastolic velocities and the resistive index (PS, ED, RI) were performed and both methods showed no significant difference between groups. ADC implied no correlation with GFR (r = 0.198, p = 0.464), while PS indicated moderate correlation to GFR (r = 0.48, p < 0.05), and PS and ED moderate correlation to cRBF (r = 0.58, p < 0.05, r = 0.56, p < 0.05, respectively). Cortical perfusion as non-invasively measured by ASL-MRI differs between patients with good and impaired allograft function and correlates significantly with its function.

A Topologically Engineered Gold Island for Programmed In Vivo Stem Cell Manipulation

AbstractEven a well‐designed system can only control stem cell adhesion, release, and differentiation, while other cell manipulations such as in situ labeling and retention in target tissues, are difficult to achieve in the same system. Herein, native ligand cluster‐mimicking islands, composed of topologically engineered ligand, anchoring point AuNP, nuclease mimetics CeIV complexes and magnetic core Fe3O4, are designed to facilitate comprehensive cell manipulations in a programmable manner. Three islands with different amounts of AuNPs are constructed, which means tunable interligand spacing within a cluster. These nanostructures are chemically coupled to a substrate using DNA tethers. Under a tissue‐penetrative magnetic field, this integrated system promotes stem cell adhesion, proliferation, mechanosensing, differentiation, detachment, in situ effective magnetic labeling and retention both in vitro and in vivo, offering fascinating opportunities for a biomimetic matrix in regenerative medicine.

A Topologically Engineered Gold Island for Programmed In Vivo Stem Cell Manipulation.

Even a well-designed system can only control stem cell adhesion, release, and differentiation, while other cell manipulations such as in situ labeling and retention in target tissues, are difficult to achieve in the same system. Herein, native ligand cluster-mimicking islands, composed of topologically engineered ligand, anchoring point AuNP, nuclease mimetics CeIV complexes and magnetic core Fe3 O4 , are designed to facilitate comprehensive cell manipulations in a programmable manner. Three islands with different amounts of AuNPs are constructed, which means tunable interligand spacing within a cluster. These nanostructures are chemically coupled to a substrate using DNA tethers. Under a tissue-penetrative magnetic field, this integrated system promotes stem cell adhesion, proliferation, mechanosensing, differentiation, detachment, in situ effective magnetic labeling and retention both in vitro and in vivo, offering fascinating opportunities for a biomimetic matrix in regenerative medicine.

Magnetic labeling of primary murine monocytes using very small superparamagnetic iron oxide nanoparticles.

Due to their very small size, nanoparticles can interact with all cells in the central nervous system. One of the most promising nanoparticle subgroups are very small superparamagnetic iron oxide nanoparticles (VSOP) that are citrate coated for electrostatic stabilization. To determine their influence on murine blood-derived monocytes, which easily enter the injured central nervous system, we applied VSOP and carboxydextran-coated superparamagnetic iron oxide nanoparticles (Resovist). We assessed their impact on the viability, cytokine, and chemokine secretion, as well as iron uptake of murine blood-derived monocytes. We found that (1) the monocytes accumulated VSOP and Resovist, (2) this uptake seemed to be nanoparticle- and time-dependent, (3) the decrease of monocytes viability was treatment-related, (4) VSOP and Resovist incubation did not alter cytokine homeostasis, and (5) overall a 6-hour treatment with 0.75 mM VSOP-R1 was probably sufficient to effectively label monocytes for future experiments. Since homeostasis is not altered, it is safe to label blood-derived monocles with VSOP. VSOP labeled monocytes can be used to study injured central nervous system sites further, for example with drug-carrying VSOP.

695 Upregulated monocyte expression of PLIN2 is associated with plaque instability in coronary artery disease

Abstract Aims Perilipin 2 (PLIN2), a protein associated with intracellular lipid droplets (LDs), is involved in lipid metabolism of macrophages resident in atherosclerotic plaques and its up-regulation leads to LDs accumulation. LDs enlargement results in the macrophage transformation into foam cells, a key step for the onset of atherosclerosis. In the present study, we investigated the role of PLIN2 and its regulation mechanisms in atherosclerosis and plaque instability in patients with a diagnosis of ST-elevation myocardial infarction (STEMI) and stable chronic angina (SA). Methods and results We enrolled 120 patients with a diagnosis of STEMI and 42 SA patients with symptoms of stable effort angina lasting more than 12 months. Peripheral blood mononuclear cells (PBMCs) were isolated from EDTA whole blood samples through standard gradient centrifugation over Ficoll-Hypaque. Monocytes were purified through indirect magnetic labelling of PBMCs. PLIN2 mRNA expression was investigated by Real Time-PCR and PLIN2 protein level was analysed in CD14+ monocytes by flow cytometry. Proteasome activity was assayed using AMC-tagged peptide substrate (Succ-LLVY-AMC), which releases free highly fluorescent AMC (Ex/Em 350/440 nm) in the presence of proteolytic activity. In CD14+ monocyte, PLIN2 protein expression was significantly increased in STEMI as compared to SA patients (P &amp;lt; 0.001), while PLIN2 mRNA level was not different in the two groups (P = n.s.). Despite proteasome activity was higher in STEMI as compared to SA patients (P &amp;lt; 0.001), significant inverse correlations were evident between PLIN2 levels and proteasome activity in the two groups (P = 0.05). Conclusions CD14+ monocyte PLIN2 protein expression was higher in STEMI as compared to SA patients suggesting an involvement in plaque instability. Despite proteasome activity was higher in STEMI patients, probably due to the elevated inflammatory burden, PLIN2 could escape proteasome degradation in a more efficient manner in STEMI as compared to SA patients.

An Overview for the Nanoparticles-Based Quantitative Lateral Flow Assay.

The development of the lateral flow assay (LFA) has received much attention in both academia and industry because of their broad applications to food safety, environmental monitoring, clinical diagnosis, and so forth. The user friendliness, low cost, and easy operation are the most attractive advantages of the LFA. In recent years, quantitative detection has become another focus of LFA development. Here, the most recent studies of quantitative LFAs are reviewed. First, the principles and corresponding formats of quantitative LFAs are introduced. In the biomaterial and nanomaterial sections, the detection, capture, and signal amplification biomolecules and the optical, fluorescent, luminescent, and magnetic labels used in LFAs are described. The invention of dedicated strip readers has drawn further interest in exploiting the better performance of LFAs. Therefore, next, the development of dedicated reader devices is described and the usefulness and specifications of these devices for LFAs are discussed. Finally, the applications of LFAs in the detection of metal ions, biotoxins, pathogenic microorganisms, veterinary drugs, and pesticides in the fields of food safety and environmental health and the detection of nucleic acids, biomarkers, and viruses in clinical analyses are summarized.

Encapsulin Based Self-Assembling Iron-Containing Protein Nanoparticles for Stem Cells MRI Visualization

Over the past decade, cell therapy has found many applications in the treatment of different diseases. Some of the cells already used in clinical practice include stem cells and CAR-T cells. Compared with traditional drugs, living cells are much more complicated systems that must be strictly controlled to avoid undesirable migration, differentiation, or proliferation. One of the approaches used to prevent such side effects involves monitoring cell distribution in the human body by any noninvasive technique, such as magnetic resonance imaging (MRI). Long-term tracking of stem cells with artificial magnetic labels, such as magnetic nanoparticles, is quite problematic because such labels can affect the metabolic process and cell viability. Additionally, the concentration of exogenous labels will decrease during cell division, leading to a corresponding decrease in signal intensity. In the current work, we present a new type of genetically encoded label based on encapsulin from Myxococcus xanthus bacteria, stably expressed in human mesenchymal stem cells (MSCs) and coexpressed with ferroxidase as a cargo protein for nanoparticles’ synthesis inside encapsulin shells. mZip14 protein was expressed for the enhancement of iron transport into the cell. Together, these three proteins led to the synthesis of iron-containing nanoparticles in mesenchymal stem cells—without affecting cell viability—and increased contrast properties of MSCs in MRI.

Micro-Solenoid Coil Design and Fabrication for Magnetic Labeled Cell and Antibody Detection

Introduction There has been considerable interest in developing techniques to create three-dimensional micro-solenoids for microfluidic devices for use with magnetic materials. Although micro-solenoids have been developed for miniaturization of inductors for on-chip power supplies and dc-dc voltage converters [1] there has been limited use in microfluidic devices [2]. Although photolithographically defined two-dimensional, planar micro solenoids have been developed, when a 3D geometry coils is required they are limited to larger scales in the millimeter range or the micro solenoids are not hollow and are filled with material, thus cannot be used with a microfluidic channel [3]. In our work we have developed a fabrication process for a 75-micron radius, vacuum micro solenoid embedded in PDMS channel for microfluidics applications [4].The applications for micro-solenoids in Bio-Micro-Fluidic systems which range from cell sorting and filtering, to the detection and analysis of individual cells. We have also demonstrated when particles in fluid pass through the coil they can be easily detected from the inducted current in the coil [4]. This approach requires much less power than a flow cytometry laboratory instrument, which requires a laser source to detect the cells and particles. Method and Results The construction of the prototype solenoid is as follows: A piece of optical fiber is held taught, and a coil of 20-30 turns of 46ga enameled wire is wound around it. A small, hollow cylindrical magnet is threaded around the coil and fiber, and the arrangement is placed in a 3d printed mold. Syringe needles are threaded onto the fiber and inserted into holes in the mold. Polydimethylsiloxane potting compound is mixed and poured into the mold. The mold and PDMS is placed in a vacuum chamber for 30 minutes to de-gas. The PDMS is cured on a hot plate on low for about 4 hours. The needles are removed and the fiber is pulled out of the PDMS using pliers wrapped in tape. Discussion and Conclusions The image in figure 1 shows a completed micro-solenoid and the induced current readings from beads injected into the channel. The motivation for developing micro-solenoid for sensing is to increase the sensitivity, by match the diameter of micro-coil to the size of the biological cell sorting, so that individual cells can be counted using a magnetic labels attached to the cells. Such micro-solenoids can be used for the detection of labelled cells with magnetic beads attached in an immunoassay. They can be used for counting magnetic particles, or measuring the size of magnetization intensity of particles, based upon the induced current in the micro-coil. Ultimately, the method could be developed for detection of individual pathogenic bacteria or even viruses in a biological sample.

Magnetoimpedance of CoFeCrSiB Ribbon-Based Sensitive Element with FeNi Covering: Experiment and Modeling.

Soft magnetic materials are widely requested in electronic and biomedical applications. Co-based amorphous ribbons are materials which combine high value of the magnetoimpedance effect (MI), high sensitivity with respect to the applied magnetic field, good corrosion stability in aggressive environments, and reasonably low price. Functional properties of ribbon-based sensitive elements can be modified by deposition of additional magnetic and non-ferromagnetic layers with required conductivity. Such layers can play different roles. In the case of magnetic biosensors for magnetic label detection, they can provide the best conditions for self-assembling processes in biological experiments. In this work, magnetic properties and MI effect were studied for the cases of rapidly quenched Co67Fe3Cr3Si15B12 amorphous ribbons and magnetic Fe20Ni80/Co67Fe3Cr3Si15B12/Fe20Ni80 composites obtained by deposition of Fe20Ni80 1 μm thick films onto both sides of the ribbons by magnetron sputtering technique. Their comparative analysis was used for finite element computer simulations of MI responses with different types of magnetic and conductive coatings. The obtained results can be useful for the design of MI sensor development, including MI biosensors for magnetic label detection.

Characterization of Glioblastoma Cancer Stem Cells Sorted by Sedimentation Field-Flow Fractionation Using an Ultrahigh-Frequency Range Dielectrophoresis Biosensor.

Cancer stem cells (CSCs) appear to be an essential target for cancer therapies, in particular, in brain tumors such as Glioblastoma. Nevertheless, their isolation is made difficult by their low content in culture or tumors (<5% of the tumor mass) and is essentially based on the use of fluorescent or magnetic labeling techniques, increasing the risk of differentiation induction. The use of label-free separation methods such as sedimentation field-flow fractionation (SdFFF) is promising, but it becomes necessary to consider a coupling with a detection and characterization method for future identification and purification of CSCs from patient-derived tumors. In this study, we demonstrate for the first time the capability of using an ultrahigh-frequency range dielectrophoresis fluidic biosensor as a detector. This implies an important methodological adaptation of SdFFF cell sorting by the use of a new compatible carrier liquid DEP buffer (DEP-B). After SdFFF sorting, subpopulations derived from U87-MG and LN18 cell lines undergo biological characterization, demonstrating that using DEP-B as a carrier liquid, we sorted by SdFFF subpopulations with specific differentiation characteristics: F1 = differentiated cells/F2 = CSCs. These subpopulations presented high-frequency crossover (HFC) values similar to those measured for standard differentiated (around 110 MHz) and CSC (around 80 MHz) populations. This coupling appeared as a promising solution for the development of an online integration of these two complementary label-free separation/detection technologies.

MP22-16 DEVELOPMENT OF NON-INVASIVE CLINICALLY APPLICABLE IN VIVO TRACKING OF EXTRACELLULAR VESICLES USING MAGNETIC RESONANCE IMAGING (MRI)

You have accessJournal of UrologyImaging/Radiology: Uroradiology II (MP22)1 Sep 2021MP22-16 DEVELOPMENT OF NON-INVASIVE CLINICALLY APPLICABLE IN VIVO TRACKING OF EXTRACELLULAR VESICLES USING MAGNETIC RESONANCE IMAGING (MRI) Johnny Akers, Paola Aguiari, Hasmik Soloyan, Seda Mkhitaryan, Gevorg Karaptyan, Roger De Filippo, Mya Thu, Laura Perin, and Sargis Sedrakyan Johnny AkersJohnny Akers More articles by this author , Paola AguiariPaola Aguiari More articles by this author , Hasmik SoloyanHasmik Soloyan More articles by this author , Seda MkhitaryanSeda Mkhitaryan More articles by this author , Gevorg KaraptyanGevorg Karaptyan More articles by this author , Roger De FilippoRoger De Filippo More articles by this author , Mya ThuMya Thu More articles by this author , Laura PerinLaura Perin More articles by this author , and Sargis SedrakyanSargis Sedrakyan More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002013.16AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Extracellular vesicles (EVs) derived from amniotic fluid stem cells (AFSC) hold great potential for the treatment of chronic kidney diseases (CKD). We have already shown that AFSC-EVs are renoprotective in a mouse model of CKD, Alport syndrome. However, there is an important unmet need for real-time in vivo monitoring of these therapeutic EVs after they are injected into a subject to understand their safety, targeting, and effectiveness. While current optical imaging solutions like bioluminescence and fluorescence are useful for EV tracking studies in animal models, there is limited utility in clinical applications. Here we present a novel in vivo tracking solution for our therapeutic EVs in Alport mice, utilizing clinically applicable MRI technology. METHODS: To generate trackable EVs, AFSC were labeled with a novel magnetic agent (VSCM). EVs secreted by the labeled AFSC were isolated by ultracentrifugation. The viability and morphology of labeled-cells were evaluated, and the in vitro MR properties of EVs were analyzed by magnetometer. Purity, potency and identity of labeled EV was compared to non-labeled EVs. In vivo biodistribution of labeled EVs was evaluated in WT and Alport mice by MRI at 10 min and 3 hr post injection, and retro-orbital and intra-cardiac routes of delivery were compared. RESULTS: The magnetic label did not affect the physiological characteristics of the cells and did not change identity, purity and potency (therapeutic effect in vivo) of EVs. MRI phantom studies confirmed the in vitro/ex vivo detectability of labeled-EVs. Importantly, as expected MRI studies showed that EV homing to the kidney injected intra-cardiacally into Alport mice was more efficient vs the retro-orbital route, and Prussian blue staining of sections confirmed EV homing to the kidney. CONCLUSIONS: We have developed a clinically applicable novel magnetic nanoparticle agent that can be used to label and track the biodistribution of EVs in the kidney and other organs using non-invasive, safe, and effective MRI technology that’s widely available. This technology is highly adaptable and can be deployed in both preclinical and clinical settings. Source of Funding: The GOFARR Fund; Research Career Development Award, TSRI, CHLA © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e397-e398 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Johnny Akers More articles by this author Paola Aguiari More articles by this author Hasmik Soloyan More articles by this author Seda Mkhitaryan More articles by this author Gevorg Karaptyan More articles by this author Roger De Filippo More articles by this author Mya Thu More articles by this author Laura Perin More articles by this author Sargis Sedrakyan More articles by this author Expand All Advertisement Loading ...

Highly aminated iron oxide nanoworms for simultaneous manufacturing and labeling of chimeric antigen receptor T cells

Cell based therapies including chimeric antigen receptor (CAR) T cells are promising for treating leukemias and solid cancers. At the same time, there is interest in enhancing the functionality of these cells via surface decoration with nanoparticles (backpacking). Magnetic nanoparticle cell labeling is of particular interest due to opportunities for magnetic separation, in vivo manipulation, drug delivery and magnetic resonance imaging (MRI). While modification of T cells with magnetic nanoparticles (MNPs) was explored before, we questioned whether MNPs are compatible with CAR-T cells when introduced during the manufacturing process. We chose highly aminated 120 nm crosslinked iron oxide nanoworms (CLIO NWs, ~36,000 amines per NW) that could efficiently label different adherent cell lines and we used CD123 CAR-T cells as the labeling model. The CD123 CAR-T cells were produced in the presence of CLIO NWs, CLIO NWs plus protamine sulfate (PS), or PS only. The transduction efficiency of lentiviral CD123 CAR with only NWs was ~ 23% lower than NW + PS and PS groups (~33% and 35%, respectively). The cell viability from these three transduction conditions was not reduced within CAR-T cell groups, though lower compared to non-transduced T cells (mock T). Use of CLIO NWs instead of, or together with cationic protamine sulfate for enhancement of lentiviral transduction resulted in comparable levels of CAR expression and viability but decreased the proportion of CD8 + cells and increased the proportion of CD4 + cells. CD123 CAR-T transduced in the presence of CLIO NWs, CLIO NWs plus PS, or PS only, showed similar level of cytotoxicity against leukemic cell lines. Furthermore, fluorescence microscopy imaging demonstrated that CD123 CAR-T cells labeled with CLIO NW formed rosettes with CD123 + leukemic cells as the non-labeled CAR-T cells, indicating that the CAR-T targeting to tumor cells has maintained after CLIO NW labeling. The in vivo trafficking of the NW labeled CAR-T cells showed the accumulation of CAR-T labeled with NWs primarily in the bone marrow and spleen. CAR-T cells can be magnetically labeled during their production while maintaining functionality using the positively charged iron oxide NWs, which enable the in vivo biodistribution and tracking of CAR-T cells.

Evidence to support magnetic resonance conditional labelling of all pacemaker and defibrillator leads in patients with cardiac implantable electronic devices.

AimsMany cardiac pacemakers and defibrillators are not approved by regulators for magnetic resonance imaging (MRI). Even following generator exchange to an approved magnetic resonance (MR)-conditional model, many systems remain classified ‘non-MR conditional’ due to the leads. This classification makes patient access to MRI challenging, but there is no evidence of increased clinical risk. We compared the effect of MRI on non-MR conditional and MR-conditional pacemaker and defibrillator leads.Methods and resultsPatients undergoing clinical 1.5T MRI with pacemakers and defibrillators in three centres over 5 years were included. Magnetic resonance imaging protocols were similar for MR-conditional and non-MR conditional systems. Devices were interrogated pre- and immediately post-scan, and at follow-up, and adverse clinical events recorded. Lead parameter changes peri-scan were stratified by MR-conditional labelling. A total of 1148 MRI examinations were performed in 970 patients (54% non-MR conditional systems, 39% defibrillators, 15% pacing-dependent) with 2268 leads. There were no lead-related adverse clinical events, and no clinically significant immediate or late lead parameter changes following MRI in either MR-conditional or non-MR conditional leads. Small reductions in atrial and right ventricular sensed amplitudes and impedances were similar between groups, with no difference in the proportion of leads with parameter changes greater than pre-defined thresholds (7.1%, 95% confidence interval: 6.1–8.3).ConclusionsThere was no increased risk of MRI in patients with non-MR conditional pacemaker or defibrillator leads when following recommended protocols. Standardizing MR conditions for all leads would significantly improve access to MRI by enabling patients to be scanned in non-specialist centres, with no discernible incremental risk.

Mesenchymal Stem Cells Do Not Lose Direct Labels Including Iron Oxide Nanoparticles and DFO-89Zr Chelates through Secretion of Extracellular Vesicles.

Rapidly ageing populations are beset by tissue wear and damage. Stem cell-based regenerative medicine is considered a solution. Years of research point to two important aspects: (1) the use of cellular imaging to achieve sufficient precision of therapeutic intervention, and the fact that (2) many therapeutic actions are executed through extracellular vesicles (EV), released by stem cells. Therefore, there is an urgent need to interrogate cellular labels in the context of EV release. We studied clinically applicable cellular labels: superparamagnetic iron oxide nanoparticles (SPION), and radionuclide detectable by two main imaging modalities: MRI and PET. We have demonstrated effective stem cell labeling using both labels. Then, we obtained EVs from cell cultures and tested for the presence of cellular labels. We did not find either magnetic or radioactive labels in EVs. Therefore, we report that stem cells do not lose labels in released EVs, which indicates the reliability of stem cell magnetic and radioactive labeling, and that there is no interference of labels with EV content. In conclusion, we observed that direct cellular labeling seems to be an attractive approach to monitoring stem cell delivery, and that, importantly, labels neither locate in EVs nor affect their basic properties.