Monitoring Nanoscale Deformations in a Drawn Polymer Melt with Single-Molecule Fluorescence Polarization Microscopy

Elongating a polymer melt causes polymer segments to align and polymer coils to deform along the drawing direction. Despite the importance of this molecular response for understanding the viscoelastic properties and relaxation behavior of polymeric materials, studies on the single-molecule level are rare and were not performed in real time. Here we use single-molecule fluorescence polarization microscopy for monitoring the position and orientation of single fluorescent perylene diimide molecules embedded in a free-standing thin film of a polymethyl acrylate (PMA) melt with a time resolution of 500 ms during the film drawing and the subsequent stress relaxation period. The orientation distribution of the perylene diimide molecules is quantitatively described with a model of rod-like objects embedded in a uniaxially elongated matrix. The orientation of the fluorescent probe molecules is directly coupled to the local deformation of the PMA melt, which we derive from the distances between individual dye molecules. In turn, the fluorescence polarization monitors the shape deformation of the polymer coils on a length scale of 5 nm. During stress relaxation, the coil shape relaxes four times more slowly than the mechanical stress. This shows that stress relaxation involves processes on length scales smaller than a polymer coil. Our work demonstrates how optical spectroscopy and microscopy can be used to study the coupling of individual fluorescent probe molecules to their embedding polymeric matrix and to an external mechanical stimulus on the single-molecule level

Optical Tracking of Single Ag Clusters in Nanostructured Water Films

The spatial diffusion and size distribution of monodisperse silver nanoclusters synthesized via Ag­(I) carboxylate in zeolite Y cages are investigated in nanostructured water films on silicon dioxide (SiO₂) and mica surfaces with optical and atomic force techniques. Subnanometer clusters escaping the zeolite Y cage show a strong and photostable fluorescence emission in the visible range and allow for optical single-cluster tracking. Heterogeneous diffusion dynamics reflect the transition from an ice-like to a liquid-like water film as a function of film thickness. The contributions of the different diffusion coefficients strongly correlate with the water film thickness and the chemical composition of the interface. The heterogeneity of the diffusion is caused by ad- and desorption of Ag clusters to silanol groups at the SiO₂ interface which couple vibronically to the Ag clusters as can be seen from single cluster fluorescence spectra

Optical Tracking of Single Ag Clusters in Nanostructured Water Films

The spatial diffusion and size distribution of monodisperse silver nanoclusters synthesized via Ag­(I) carboxylate in zeolite Y cages are investigated in nanostructured water films on silicon dioxide (SiO₂) and mica surfaces with optical and atomic force techniques. Subnanometer clusters escaping the zeolite Y cage show a strong and photostable fluorescence emission in the visible range and allow for optical single-cluster tracking. Heterogeneous diffusion dynamics reflect the transition from an ice-like to a liquid-like water film as a function of film thickness. The contributions of the different diffusion coefficients strongly correlate with the water film thickness and the chemical composition of the interface. The heterogeneity of the diffusion is caused by ad- and desorption of Ag clusters to silanol groups at the SiO₂ interface which couple vibronically to the Ag clusters as can be seen from single cluster fluorescence spectra

Additional file 1: Table S1. of Inhibition of IGF1-R overcomes IGFBP7-induced chemotherapy resistance in T-ALL

Probe sets in the IGF1-R signatures that are over-expressed in the high IGF1-R group. Table S2. Probe sets in the IGF1-R signatures that are under-expressed in the high IGF1-R group. (PDF 209 kb

Molecular characteristics of <i>FLT3</i>mut ETP-ALL versus <i>FLT3</i>wt ETP-ALL patients.

<p>A: P-values were calculated by Mann-Whitney-U-test.</p><p>B: P-values were calculated by Pearson's Chi-square test and Fisher's exact test, respectively.</p

Combinations of antigens as a surrogate marker for <i>FLT3</i> mutations in ETP-ALL.

<p>Abbreviations:</p>§<p>combination of markers suggested by Hoehn <i>et al.</i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053190#pone.0053190-Hoehn1" target="_blank">[17]</a>,</p>#<p>combination of markers suggested by Paietta <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053190#pone.0053190-Paietta2" target="_blank">[36]</a>,</p>&<p>combination of markers suggested in this paper. All combinations were adapted to the subgroup of ETP-ALL.</p

Kaplan Meier analysis of overall survival in adult ETP-ALL patients receiving chemotherapy only (without alloSCT) or undergoing alloSCT.

<p>P-value was calculated by the Log-Rank test. Abbreviations: alloSCT, allogeneic stem cell transplantation.</p

Effects of tyrosine kinase inhibitors on proliferation in T-ALL cell lines transfected with FLT3 expression constructs (A–C).

<p>Fourty-eight hours (hrs) after transfection, cells were seeded and cultured for additionally 48 hrs with tyrosine kinase inhibitors (PKC412, TKI258, and Sorafenib) and chemotherapy (AraC). Cell proliferation was measured using the WST-1 proliferation reagent. The mean optical density (OD) values corresponding to non-treated FLT3-ITD transfected cells were taken as 100%. The results were expressed in percentages of the OD of treated versus untreated control cells. Two experiments were performed in duplicates. For each drug two different doses were used. All results were expressed as means ±S.D. <b>A</b>: Jurkat cells. <b>B</b>: MOLT4 cells. <b>C</b>: BE13 cells.</p

Mutational events in ETP-ALL compared to non-ETP T-ALL.

<p>P values were calculated by Pearson's Chi-square test and Fisher's exact test, respectively.</p