An oligonucleotide microarray for microRNA expression analysis based on labeling RNA with quantum dot and nanogold probe

MicroRNAs (miRNAs) play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression. They have diverse expression patterns and might regulate various developmental and physiological processes. Profiling miRNA expression is very helpful for studying biological functions of miRNAs. We report a novel miRNA profiling microarray, in which miRNAs were directly labeled at the 3′ terminus with biotin and hybridized with complementary oligo-DNA probes immobilized on glass slides, and subsequently detected by measuring fluorescence of quantum dots labeled with streptavidin bound to miRNAs through streptavidin–biotin interaction. The detection limit of this microarray for miRNA was ∼0.4 fmol, and the detection dynamic range spanned about 2 orders of magnitude. We made a model microarray to profile 11 miRNAs from leaf and root of rice (Oryza sativa L. ssp. indica) seedlings. The analysis results of the miRNAs had a good reproducibility and were consistent with the northern blot result. To avoid using high-cost detection equipment, colorimetric detection, a method based on nanogold probe coupled with silver enhancement, was also successfully introduced into miRNA profiling microarray detection

Three-dimensional constructs using hyaluronan cell carrier as a tool for the study of cancer stem cells

Background: Cancer research focuses increasingly on cancer stem cell study as those cells are thought to be the root of chemo and radioresistance of the most aggressive cancer types. Nevertheless, two-dimensional (2D) cell culture and even three-dimensional (3D) spheroid models, with their limited ability to reflect cell-extracellular matrix interactions, are not ideal for the study of cancer stem cells (CSCs). In this study, we establish a 3D in vitro cancer model using a synthetic and natural scaffold with tunable features and show that U87 cells cultured in this system acquire a stem-cell like phenotype. Methods: U87 astrocytoma cells were grown on polycaprolactone (PCL)-2D flat substrates (2D) and PCL-3D scaffolds (3D) eventually containing hyaluronic acid (3D-HA). Cell viability, growth patterns, morphology, and cell surface marker expression (CD44, RHAMM and CD133) were studied to assess the effect of 3D culture and presence of HA. Results: 3D scaffold, but most prominently presence of HA induced changes in cell morphology and marker expression; 3D-HA cultures showed features of aggregates; moreover, markedly increased expression of Nestin, CD44, RHAMM, and CD133 in 3D-HA scaffolds were found. Conclusions: the behavior of U87 in our 3D-HA model is more similar to tumor growth in vivo and a stem-like phenotype is promoted. Thus, the 3D-HA scaffold could provide a useful model for CSCs study and anti-cancer therapeutics research in vitro and may have preclinical application for the screening of drug candidates. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1249-1257, 2015.Contract grant sponsors: National R&D&i Plan (2008-2011; CIBER-BBN), Iniciativa Ingenio 2010, Consolider Program, CIBER Actions, and Instituto de Salud Carlos III (European Regional Development Fund)Martínez Ramos, C.; Lebourg, M. (2015). Three-dimensional constructs using hyaluronan cell carrier as a tool for the study of cancer stem cells. Journal of Biomedical Materials Research Part B: Applied Biomaterials. 103(6):1249-1257. https://doi.org/10.1002/jbm.b.33304S12491257103

Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg ×{\times} day Data of the CDEX-10 Experiment

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8 $\times 10^{-42}$ and 3 $\times 10^{-36}$ cm$^{2}$ at a 90\% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass ($m_{\chi}$) of 5 GeV/${c}^2$ are achieved. The lower reach of $m_{\chi}$ is extended to 2 GeV/${c}^2$.Comment: 5 pages, 4 figure