We analyze a series of publicly available controlled experiments (Latin square) on Affymetrix high density oligonucleotide microarrays using a simple physical model of the hybridization process. We plot for each gene the signal intensity versus the hybridization free energy of RNA/DNA duplexes in solution, for perfect matching and mismatching probes. Both values tend to align on a single master curve in good agreement with Langmuir adsorption theory, provided one takes into account the decrease of the effective target concentration due to target-target hybridization in solution. We give an example of a deviation from the expected thermodynamical behavior for the probe set 1091 at due to annotation problems, i.e. the surface-bound probe is not the exact complement of the target RNA sequence, because of errors present in public databases at the time when the array was designed. We show that the parametrization of the experimental data with RNA/DNA free energy improves the quality of the fits and enhances the stability of the fitting parameters compared to previous studies.

In this article, we describe an efficient physical electric‐field‐assisted method to study self‐assembly and orientation of cellulose nanocrystals. When applying an alternating voltage to a cellulose nanocrystals suspension deposited onto a thin gap of coplanar lithographically patterned metallic electrodes, a highly homogeneous orientation of cellulose nanocrystals is obtained. Parameters such as strength and frequency of the applied electric field and cellulose nanocrystals aspect ratios were studied to determine how they affect cellulose nanocrystals assembly and orientation. The prepared films were analyzed by atomic force microscopy, and the results suggest that the alignment of cellulose nanocrystals generated films is greatly influenced by the frequency and the strength of the applied electric field. The orientation of cellulose nanocrystals becomes more homogeneous with increasing electric field higher than 2000 V/cm with a frequency ranging between 104 and 106 Hz. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1430–1436, 2008

Electrons and holes are locally injected in a single pentacene monolayer island. The twodimensional distribution and concentration of the injected carriers are measured by electrical force microscopy. In crystalline monolayer islands, both carriers are delocalized over the whole island. On disordered monolayer, carriers stay localized at their injection point. These results provide insight into the electronic properties, at the nanometer scale, of organic monolayers governing performances of organic transistors and molecular devices.

We have described in the accompanying article the preparation of peptide-protein semicarbazide microarrays and their use for the simultaneous serodetection of antibodies directed against different pathogens. Here, we present a comparative study between semicarbazide and amine glass slides in an immunofluorescent serodetection assay using HIV (Gp120, Gp41), HCV (mix-HCV, core, NS3, and NS4), and HBV (HBs) recombinant antigens. Amine and semicarbazide surfaces displayed the same sensitivity for antibodies detection just after printing. However, the reactivity of protein antigens changed rapidly upon aging on amine slides but not on semicarbazide slides. Peptide or protein semicarbazide microarrays were found to be remarkably stable for months. Additional data concerning the characterization of the semicarbazide surface (homogeneity of the slides, chemical stability, contact angle measurements, atomic force microscopy studies, reproducibility of serodetection results) are also presented and discussed.