High-resolution epifluorescence and time-of-flight secondary ion mass spectrometry chemical imaging comparisons of single DNA microarray spots.

DNA microarray assay performance is commonly compromised by spot-spot probe and signal variations as well as heterogeneity within printed microspots. Accurate metrics for captured DNA target signal rely upon uniform spot distribution of both probe and target DNA to yield reliable hybridized signal. While often presumed, this is neither easily achieved nor often proven experimentally.

Evidence of the synergetic role of charged species and atomic oxygen in the molecular etching of PTFE surfaces for hydrophobic surface synthesis.

The transformation of a poly(tetrafluoroethylene) (PTFE) hydrophobic surface into a superhydrophobic one using a low pressure RF plasma is explored using optical emission spectrometry (OES), X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) measurements, mass measurements, and atomic force microscopy (AFM). It is shown that the increase in contact angle is due to an increase of roughness provoked by a chemical etching of the surface. We propose a molecular mechanism for etching that requires the simultaneous presence of atomic oxygen and negatively charged species (electrons) at the PTFE surface.

Study of plasma modified-PTFE for biological applications: relationship between protein resistant properties, plasma treatment, surface composition and surface roughness.

PTFE samples were treated by low-pressure, O RF plasmas. The adsorption of BSA was used as a probe for the protein resistant properties. The exposure of PTFE to an O plasma leads to an increase in the chamber pressure.