Magnetophoresis and the magnetic susceptibility of HeLa tumor cells

Kashevskii, B. É.; Kashevskii, S. B.; Прохоров, И. В.; Aleksandrova, E. N.; Istomin, Yu. P.

doi:10.1134/s0006350906060091

Cited by 14 publications

(8 citation statements)

References 11 publications

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“…Early work based on fluorescence-activated cell sorting (FACS) analysis [27, 30] for CTCs was limited due to a requirement of high throughput for rare event detection [31, 32]. Even newer technologies for positive capture rely on differences in physical properties between the transformed and normal cells, such as those used for size filtration [33-35], label-free dielectric [36, 37] and magnetic [38, 39] separations. Advances in microscopy and high throughput imaging instrumentation made it possible to visualize and count CTCs directly in blood leukocyte smears [40, 41] and have raised issues of potential false negative results [42-45].…”

Section: Discussionmentioning

confidence: 99%

Enrichment of circulating melanoma cells (CMCs) using negative selection from patients with metastatic melanoma

et al. 2014

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Circulating tumor cells have emerged as prognostic biomarkers in the treatment of metastatic cancers of epithelial origins viz., breast, colorectal and prostate. These tumors express Epithelial Cell Adhesion Molecule (EpCAM) on their cell surface which is used as an antigen for immunoaffinity capture. However, EpCAM capture technologies are of limited utility for non-epithelial cancers such as melanoma.We report a method to enrich Circulating Melanoma Cells (CMCs) that does not presuppose malignant cell characteristics. CMCs were enriched by centrifugation of blood samples from healthy (N = 10) and patient (N = 11) donors, followed by RBC lysis and immunomagnetic depletion of CD45-positive leukocytes in a specialized magnetic separator. CMCs were identified by immunocytochemistry using Melan-A or S100B as melanoma markers and enumerated using automated microscopy image analyses. Separation was optimized for maximum sensitivity and recovery of CMCs.Our results indicate large number of CMCs in Stage IV melanoma patients. Analysis of survival suggested a trend toward decreased survival with increased number of CMCs. Moreover, melanoma-associated miRs were found to be higher in CMC-enriched fractions in two patients when compared with the unseparated samples, validating this method as applicable for molecular analyses.Negative selection is a promising approach for isolation of CMCs and other EpCAM -negative CTCs, and is amenable to molecular analysis of CMCs. Further studies are required to validate its efficacy at capturing specific circulating cells for genomic analysis, and xenograft studies.

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Section: Discussionmentioning

confidence: 99%

Enrichment of circulating melanoma cells (CMCs) using negative selection from patients with metastatic melanoma

et al. 2014

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“…However, they include a hard-to operate and expensive scheme that is not optimized for single-particle measurements. To overcome these limitations, magnetophoretic motion of particles in a nonhomogeneous magnetic field has been used for measuring volumetric susceptibilities of both nonlabeled cells (χ HeLa tumor cells : −0.5136 × 10 –6 (CGS units)) and labeled cells (χ yeast, liver, and carcinoma cells : 13–20 × 10 –6 (SI units)) . In this study, we used a magnetic levitation strategy to measure target proteins captured on microspheres with a change in the magnetic susceptibility of microspheres.…”

Section: Resultsmentioning

confidence: 99%

Magnetic Susceptibility-Based Protein Detection Using Magnetic Levitation

Yaman

Tekin

2020

Anal. Chem.

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Magnetic levitation, which is a magnetic phenomenon of levitating particles suspended in a paramagnetic liquid under a nonuniform magnetic field, is a powerful tool for determining densities and magnetic properties of micro- and nanoparticles. The levitation height of particles in the magnetic field depends on the magnetic susceptibility and density difference between the object and the surrounding liquid. Here, we developed a magnetic susceptibility-based protein detection scheme in a low-cost and miniaturized magnetic levitation setup consisting of two opposing magnets to create a gradient of a magnetic field, a glass capillary channel to retain the sample, and two side mirrors to monitor inside the channel. The method includes the use of polymeric microspheres as mobile assay surfaces and magnetic nanoparticles as labels. The assay was realized by capturing the target protein to the polymer microspheres. Then, magnetic nanoparticles were attached onto the resulting microsphere–protein complex, creating a significant difference in the magnetic properties of polymer microspheres compared to those without protein. The change in the magnetic properties caused a change in the levitation height of the microspheres. The levitation heights and their distribution were then correlated to the amount of target proteins. The method enabled a detection limit of ∼110 fg/mL biotinylated bovine serum albumin in serum. With the sandwich immunoassay developed for mouse immunoglobulin G, detection limits of 1.5 ng/mL and >10 ng/mL were achieved in buffer and serum, respectively. This approach sensed the minute changes in the volume magnetic susceptibility of the microspheres with a resolution of 4.2 × 10–8 per 1 μm levitation height change.

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“…Following others (14), in this study we used a susceptibility difference of c ¼ 6 Â 10 À7 (14) in all simulations.…”

Section: Simulationsmentioning

confidence: 99%

Susceptibility Perturbation MRI Maps Tumor Infiltration into Mesorectal Lymph Nodes

et al. 2019

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Noninvasive characterization of lymph node involvement in cancer is an enduring onerous challenge. In rectal cancer, pathologic lymph node status constitutes the most important determinant of local recurrence and overall survival, and patients with involved lymph nodes may benefit from preoperative chemo and/or radiotherapy. However, knowledge of lymph node status before surgery is currently hampered by limited imaging accuracy. Here, we introduce Susceptibility-Perturbation MRI (SPI) as a novel source of contrast to map malignant infiltration into mesorectal lymph nodes. SPI involves multigradient echo (MGE) signal decays presenting a nonmonoexponential nature, which we show is sensitive to the underlying microstructure via susceptibility perturbations. Using numerical simulations, we predicted that the large cell morphology and the high cellularity of tumor within affected mesorectal lymph nodes would induce signature SPI decays. We validated this prediction in mesorectal lymph nodes excised from total mesorectal excision specimens of patients with rectal cancer using ultrahigh field (16.4 T) MRI. SPI signals distinguished benign from malignant nodal tissue, both qualitatively and quantitatively, and our histologic analyses confirmed cellularity and cell size were the likely underlying sources for the differences observed. SPI was then adapted to a clinical 1.5 T scanner, added to patients' staging protocol, and compared with conventional assessment by two expert radiologists. Nonmonoexponential decays, similar to those observed in the ex vivo study, were demonstrated, and SPI classified lymph nodes more accurately than standard highresolution T 2 -weighted imaging assessment. These findings suggest this simple, yet highly informative, method can improve rectal cancer patient selection for neoadjuvant therapy.Significance: These findings introduce an MRI methodology tailored to detect magnetic susceptibility perturbations induced by subtle alterations in tissue microstructure.

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Magnetophoresis and the magnetic susceptibility of HeLa tumor cells

Cited by 14 publications

References 11 publications

Enrichment of circulating melanoma cells (CMCs) using negative selection from patients with metastatic melanoma

Enrichment of circulating melanoma cells (CMCs) using negative selection from patients with metastatic melanoma

Magnetic Susceptibility-Based Protein Detection Using Magnetic Levitation

Susceptibility Perturbation MRI Maps Tumor Infiltration into Mesorectal Lymph Nodes

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