Apparent Molar Mass of a Polyelectrolyte in an Organic Solvent in the Low Ionic Strength Limit As Revealed by Light Scattering

The apparent molar mass of a partially quaternized poly-2-vinylpyridines (degree of quaternization 4.3% < <i>Q</i> < 35%) in 1-propanol is measured by light scattering at low ionic strength (10^–6 M < <i>c</i>_s < 10^–3 M) as a function of polyion repeat unit concentration (7 × 10^–5 monomol/L < <i>c</i>_m,p < 4 × 10^–2 monomol/L). No dialysis was applied prior to measurements. The apparent molar mass under “salt-free” conditions is smaller than the true molar mass by an order of magnitude, while approaching the true value at higher ionic strength. Concomitant data on the dependence of scattering intensity on scattering wave vector show that the dilute polyelectrolyte solutions are strongly correlated. A recent theory by Muthukumar for light scattering of dilute polyelectrolyte solutions, developed for correlated multicomponent systems, accounts for interchain electrostatic correlations and regularization of polymer charge by counterion binding isotherm. The experimental results on the relation between the apparent and true molar masses as a function of salt concentration are compared with the predictions of Muthukumar’s counterion adsorption theory. Taking binding equilibrium constant as a single fitting parameter, this theory is demonstrated to describe the experimental data as long as the chains do not interact significantly

Two new proanthocyanidin trimers isolated from <i>Cistus incanus</i> L. demonstrate potent anti-inflammatory activity and selectivity to cyclooxygenase isoenzymes inhibition

<p>Two new proanthocyanidin trimers have been isolated from <i>Cistus incanus</i> herb; gallocatechin-(4α→6)-gallocatechin-(4α→8)-gallocatechin (compound <b>1</b>) and epigallocatechin-3-O-gallate-(4ß→8)-epigallocatechin-3-O-gallate-(4ß→8)-gallocatechin (compound <b>2</b>). The structures were determined on the basis of 1D- and 2D-NMR (HSQC, HMBC) of their peracetylated derivatives, MALDI-TOF-MS and by acid-catalysed degradation with phloroglucinol. A more abundant proanthocyanidin oligomer was also isolated, purified and its chemical constitution studied by ¹³C-NMR and phloroglucinol degradation. The mean molecular weight of the polymer was estimated to be about 7 to 8 flavan-3-ol-units with a ratio of procyanidin : prodelphinidin units at 1:5, some of which are derivatised by gallic acid. Water extract and higher oligomeric proanthocyanidin fractions of <i>C. incanus</i> significantly inhibited TPA-induced oedema when applied topically at doses of 0.5 and 1 mg/ear in mice. Furthermore, the extracts and the pure compounds inhibited COX-1 and COX-2 activities. In addition, compound <b>2</b> exhibited an IC₅₀ of 4.5 μM against COX-2 indicating its high selectivity towards COX-2.</p

Single Molecule Tracking on Supported Membranes with Arrays of Optical Nanoantennas

Coupling of the localized surface plasmons between two closely apposed gold nanoparticles (nanoantenna) can cause strong enhancements of fluorescence or Raman signal intensity from molecules in the plasmonic “hot-spot”. Harnessing these properties for practical applications is challenging due to the need to fabricate gold particle arrays with well-defined nanometer spacing and a means of delivering functional molecules to the hot-spot. We report fabrication of billions of plasmon-coupled nanostructures on a single substrate by a combination of colloid lithography and plasma processing. Controlled spacing of the nanoantenna gaps is achieved by taking advantage of the fact that polystyrene particles melt together at their contact point during plasma processing. The resulting polymer thread shadows a gap of well-defined spacing between each pair of gold triangles in the final array. Confocal surface-enhanced Raman spectroscopy imaging confirms the array is functionally uniform. Furthermore, a fully intact supported membrane can be formed on the intervening substrate by vesicle fusion. Trajectories of freely diffusing individual proteins are traced as they sequentially pass through, and are enhanced by, multiple gaps. The nanoantenna array thus enables enhanced observation of a fluid membrane system without static entrapment of the molecules

Single Molecule Tracking on Supported Membranes with Arrays of Optical Nanoantennas

Coupling of the localized surface plasmons between two closely apposed gold nanoparticles (nanoantenna) can cause strong enhancements of fluorescence or Raman signal intensity from molecules in the plasmonic “hot-spot”. Harnessing these properties for practical applications is challenging due to the need to fabricate gold particle arrays with well-defined nanometer spacing and a means of delivering functional molecules to the hot-spot. We report fabrication of billions of plasmon-coupled nanostructures on a single substrate by a combination of colloid lithography and plasma processing. Controlled spacing of the nanoantenna gaps is achieved by taking advantage of the fact that polystyrene particles melt together at their contact point during plasma processing. The resulting polymer thread shadows a gap of well-defined spacing between each pair of gold triangles in the final array. Confocal surface-enhanced Raman spectroscopy imaging confirms the array is functionally uniform. Furthermore, a fully intact supported membrane can be formed on the intervening substrate by vesicle fusion. Trajectories of freely diffusing individual proteins are traced as they sequentially pass through, and are enhanced by, multiple gaps. The nanoantenna array thus enables enhanced observation of a fluid membrane system without static entrapment of the molecules

Magneto-Optical Enhancement by Plasmon Excitations in Nanoparticle/Metal Structures

Coupling magnetic materials to plasmonic structures provides a pathway to dramatically increase the magneto-optical response of the resulting composite architecture. Although such optical enhancement has been demonstrated in a variety of systems, some basic aspects are scarcely known. In particular, reflectance/transmission modulations and electromagnetic field intensification, both triggered by plasmon excitations, can contribute to the magneto-optical enhancement. However, a quantitative evaluation of the impact of both factors on the magneto-optical response is lacking. To address this issue, we have measured magneto-optical Kerr spectra on corrugated gold/dielectric interfaces with magnetic (nickel and iron oxide) nanoparticles. We find that the magneto-optical activity is enhanced by up to an order of magnitude for wavelengths that are correlated to the excitation of propagating or localized surface plasmons. Our work sheds light on the fundamental principles for the observed optical response and demonstrates that the outstanding magneto-optical performance is originated by the increase of the polarization conversion efficiency, whereas the contribution of reflectance modulations is negligible

Additional file 5 of Micro-RNA-186-5p inhibition attenuates proliferation, anchorage independent growth and invasion in metastatic prostate cancer cells

Figure S2. Up-regulation of AKAP12 in PC-3 cells and pAKT in HEK 293 T cells. A) Total RNA was collected from PC-3 cells transfected with miR-186-5p inhibitor and scramble control 72 h post-transfection. AKAP12 transcript expression was increased by 1.7-fold in transient miR-186-5p inhibited PC-3 cells relative to negative controls (p = 0.0597). B) Protein lysate (35 μg) was collected from HEK 293 T cells transfected with miR-186-5p mimic and scramble control 72 h post-transfection. pAKT expression was enhanced by 1.67-fold increase via miR-186-5p overexpression in HEK 293 T cells (p = 0.196). Data was quantitated from at least 2–3 independent experiments and are represented as mean ± S.D. (TIFF 457 kb

Additional file 3 of Micro-RNA-186-5p inhibition attenuates proliferation, anchorage independent growth and invasion in metastatic prostate cancer cells

Figure S1. Transient and stable miR-186-5p inhibition and overexpression in prostate cancer and normal epithelial cells. miR-186-5p expression was measured following 24–48 h transient post-transfection and stable transfection using qRT-PCR. A) Following transient transfection of cell models with miR-186-5p inhibitor, miR-186-5p was reduced by 33–73% in PC-3 (p = 0.0002), MDA-PCA-2b (p = 0.0061) and LNCaP (p = 0.0381) cells. B) Ectopic expression of miR-186-5p in PC-3 (p = 0.0002), MDA-PCA-2b (p = 0.0061) and LNCaP (p = 0.0381) cells transiently transfected with miR-186-5p mimic. C) MiR-186-5p expression was reduced by 30% in PC-3 cells stably transfected with pcDNA-DEST-47-anti-miR-186 compared to pcDNA-DEST-47 (empty vector) (p = 0.0022). MiR-186-5p was up-regulated by 2.55-fold in RWPE1 cells stably transfected with pcDNA-DEST-47-miR-186 mimic construct compared to the empty vector control (p = 0.0019). Data was quantitated from three independent experiments and are represented as mean fold change ± S.D. (**p-value < 0.005, ***p-value < 0.007). (TIFF 1824 kb

Additional file 1 of Micro-RNA-186-5p inhibition attenuates proliferation, anchorage independent growth and invasion in metastatic prostate cancer cells

Table S1. De-identified demographic and clinico-pathological data. Clinical data and serum from 15 men diagnosed with prostate cancer and five disease-free individuals were obtained from the BioServe Biotechnologies Biorepository (Beltsville, MD). Subjects were self-identified as European American males. There were no significant differences in median age between cases and controls (p = 0.726). Among men diagnosed with prostate cancer, 60% were diagnosed with adenocarcinoma, 66.7% were smokers, and 73.3% received two or more therapies. Relative to controls, cases had higher median serum PSA level (ng/ml) (p = 0.048) and BMI (p = 0.225) values. (DOCX 63 kb