Microscale Magnetic Field Modulation for Enhanced Capture and Distribution of Rare Circulating Tumor Cells

Immunomagnetic assay combines the powers of the magnetic separation and biomarker recognition and has been an effective tool to perform rare Circulating Tumor Cells detection. Key factors associated with immunomagnetic assay include the capture rate, which indicates the sensitivity of the system, and distributions of target cells after capture, which impact the cell integrity and other biological properties that are critical to downstream analyses. Here we present a theoretical framework and technical approach to implement a microscale magnetic immunoassay through modulating local magnetic field towards enhanced capture and distribution of rare cancer cells. Through the design of a two-dimensional micromagnet array, we characterize the magnetic field generation and quantify the impact of the micromagnets on rare cell separation. Good agreement is achieved between the theory and experiments using a human colon cancer cell line (COLO205) as the capture targets

Formation of SiC Nanocrystals Aligned at the SiO2／Si Interface Aiming at Sample Preparation for Scanning Tunneling Luminescence Spectroscopy

We investigated the synthesis of SiC nanocrystals (NCs) of several nanometers on a crystalline Si(001) surface, aiming at sample preparation for scanning tunneling luminescence using a novel conductive transparency probe. Two methods for C implantation and CO diffusion to SiO2/Si(001) samples were adopred for the formation of nanocrystalline SiC aligned on the Si(001) surface. The characterization of NCs: crystalline structure, shape, size and areal density, were analyzed by reflection high-energy electron diffraction, scanning probe microscopy and Rutherford backscattering spectroscopy. The C implantation method could not form sufficient NCs on the surface since the diffusion of C to the interface was not adequarely promoted by thermal annealing. On the other hand, almost an ideal structure of SiC NCs of ~10 nm on the Si(001) surface was realized by CO annealing under 0.2 bar at 1100 ℃ for 0.5 h. The size of NCs primarily depends on the annealing time: the annealing conditions should be optimized for further decrement of the NC size.Full-Length PaperBy a grant from Research Institute for Integrated Science, Kanagawa Universit

Infection of mesangial cells with HIV and SIV: Identification of GPR1 as a coreceptor

Infection of mesangial cells with HIV and SIV: Identification of GPR1 as a coreceptor.BackgroundMesangial cells are an important component of the glomerulus. Dysfunction of mesangial cells is thought to be involved in the development of human immunodeficiency virus type 1 (HIV-1)-associated nephropathy (HIVAN). HIVAN is a structural renal failure frequently observed in patients with acquired immune deficiency syndrome. However, the susceptibility of mesangial cells to HIV-1 is disputable. More than ten G protein-coupled receptors, including chemokine receptors, have been shown to act as HIV-1 coreceptors that determine the susceptibilities of cells to HIV-1 strains with specific cell tropisms.MethodsWe examined the susceptibility of mesangial cells to various HIV-1, HIV type 2 (HIV-2) and simian immunodeficiency virus (SIV) strains. Expression of CD4 and HIV/SIV coreceptors was examined by Western blotting and polymerase chain reaction.ResultsMesangial cells were found to be susceptible to HIV-1 variant and mutants that infect brain-derived cells, but highly resistant to T-tropic (X4), M-tropic (R5) or dual-tropic (X4R5) HIV-1 strains. In addition, mesangial cells were also susceptible to HIV-2 and SIV strains that infect the brain-derived cells. Among HIV/SIV coreceptors we tested, the expression of GPR1 mRNA was detected in mesangial cells. Expression of CD4 mRNA and protein was also detected in them. Mesangial cells and GPR1-transduced CD4-positive cells showed similar susceptibilities to the HIV-1 variant and mutants and HIV-2 and SIV strains.ConclusionsCD4 and GPR1 mRNAs were detected in mesangial cells. Mesangial cells were susceptible to HIV/SIV strains that use GPR1 as a coreceptor. Our findings suggest that an orphan G protein-coupled receptor, GPR1, is a coreceptor expressed in mesangial cells. It remains to be investigated whether the interaction of mesangial cells with specific HIV-1 strains through GPR1 plays a role in the development of HIVAN

Engineered Nanogel Particles Enhance the Photoautotrophic Biosynthesis of Polyhydroxyalkanoate in Marine Photosynthetic Bacteria

Improving polyhydroxyalkanoate (PHA, a biodegradable plastic) production under photoautotrophic cultivation is challenging for sustainable bioproduction. In this study, we demonstrated the use of engineered nanogel particles to enhance PHA accumulation in the marine photosynthetic bacterium Rhodovulum sulfidophilum under photoautotrophic culture. We screened the effect of 13 engineered nanogel particles on the cell growth and PHA accumulation of R. sulfidophilum. The addition of anionic nanogel particles significantly enhanced PHA accumulation in R. sulfidophilum up to 157-fold compared to that without nanogel particles. By performing ¹³C tracer experiments and gas chromatography–mass spectrometry analysis, we confirmed that HCO₃⁻ was assimilated throughout the central carbon metabolism and that the accumulated PHA was indeed incorporated from HCO₃⁻. Our results indicate successful PHA production with the supplementation of engineered nanogel particles under photoautotrophic cultivation in R. sulfidophilum. Furthermore, the strategy of using engineered nanoparticles demonstrated in this study may be applicable to other microbial cell factories to produce other commodity metabolites

6,6′-Dimeth­oxy-2,2′-[(hexane-1,6-diyldi­oxy)bis­(nitrilo­methyl­idyne)]diphenol

In the title compound, C22H28N2O6, strong intra­molecular O—H⋯N hydrogen bonds and weak inter­molecular C—H⋯O hydrogen bonds stabilize the three-dimensional supra­molecular structure

Screening and Molecular Analysis of Single Circulating Tumor Cells Using Micromagnet Array

Immunomagnetic assay has been developed to detect rare circulating tumor cells (CTCs), which shows clinical significance in cancer diagnosis and prognosis. The generation and fine-tuning of the magnetic field play essential roles in such assay toward effective single-cell-based analyses of target cells. However, the current assay has a limited range of field gradient, potentially leading to aggregation of cells and nanoparticles. Consequently, quenching of the fluorescence signal and mechanical damage to the cells may occur, which lower the system sensitivity and specificity. We develop a micromagnet-integrated microfluidic system for enhanced CTC detection. The ferromagnetic micromagnets, after being magnetized, generate localized magnetic field up to 8-fold stronger than that without the micromagnets, and strengthen the interactions between CTCs and the magnetic field. The system is demonstrated with four cancer cell lines with over 97% capture rate, as well as with clinical samples from breast, prostate, lung, and colorectal cancer patients. The system captures target CTCs from patient blood samples on a standard glass slide that can be examined using the fluorescence in-situ hybridization method for the single-cell profiling. All cells showed clear hybridization signals, indicating the efficacy of the compact system in providing retrievable cells for molecular studies

Early treatment with a sodium-glucose co-transporter 2 inhibitor in high-risk patients with acute heart failure:Rationale for and design of the EMPA-AHF trial

Aims: The aim of the EMPA-AHF trial is to clarify whether early initiation of a sodium-glucose co-transporter 2 inhibitor before clinical stabilization is safe and beneficial for patients with acute heart failure (AHF) who are at a high risk of adverse events. Methods: The EMPA-AHF trial is a randomized, double-blind, placebo-controlled, multicentre trial examining the efficacy and safety of early initiation of empagliflozin (10 mg once daily). In total, 500 patients admitted for AHF will be randomized 1:1 to either empagliflozin 10 mg daily or placebo at 47 sites in Japan. Study entry requires hospitalization for AHF with dyspnoea, signs of volume overload, elevated natriuretic peptide, and at least one of the following criteria: estimated glomerular filtration rate &lt;60 mL/min/1.73 m2; already taking ≥40 mg of furosemide daily before hospitalization; and urine output of &lt;300 mL within 2 hours after an adequate dose of intravenous furosemide. Patients will be randomized within 12 hours of hospital presentation, with treatment continued up to 90 days. The primary outcome is the clinical benefit of empagliflozin on the win ratio for a hierarchical composite endpoint consisting of death within 90 days, heart failure rehospitalization within 90 days, worsening heart failure during hospitalization, and urine output within 48 hours after treatment initiation. Conclusion: The EMPA-AHF trial is the first to evaluate the efficacy and safety of early initiation of empagliflozin in patients with AHF considered to be at high risk under conventional treatment.</p