Bacterial biofilms impair the operation of many industrial processes. Deinococcus geothermalis is efficient primary biofilm former in paper machine water, functioning as an adhesion platform for secondary biofilm bacteria. It produces thick biofilms on various abiotic surfaces, but the mechanism of attachment is not known. High-resolution field-emission scanning electron microscopy and atomic force microscopy (AFM) showed peritrichous adhesion threads mediating the attachment of D. geothermalis E50051 to stainless steel and glass surfaces and cell-to-cell attachment, irrespective of the growth medium. Extensive slime matrix was absent from the D. geothermalis E50051 biofilms. AFM of the attached cells revealed regions on the cell surface with different topography, viscoelasticity, and adhesiveness, possibly representing different surface layers that were patchily exposed. We used oscillating probe techniques to keep the tip-biofilm interactions as small as possible. T also formed tenacious biofilms. This paper shows that D. geothermalis has firm but laterally slippery attachment not reported before for a nonmotile species.Bacteria growing as biofilms are more resistant to many antimicrobial agents than free-swimming bacteria, a characteristic of the biofilms resulting in, e.g., persistent infections of the human body and troublesome biofilms in water distribution systems and in industrial processes (7,17,20,32). Paper mills use biocides to control microbial growth, but this has not eliminated biofilms, which may detach from surfaces, impairing operation of the machines or causing defects such as holes and colored spots in the paper products (4,16,29,30). Not all bacteria form biofilms; some machines run with 10 5 to 10 8 CFU of free-swimming bacteria ml of circulating water Ϫ1 with no process disturbances. We recently showed Deinococcus geothermalis to be an efficient primary biofilm former in paper machine water (30), functioning as an adhesion platform for secondary biofilm bacteria, e.g., Bacillus species (16). D. geothermalis forms thick biofilms on various abiotic surfaces, such as stainless steel and polystyrenes (16), glass, and polyethene, but the mechanism of attachment is not known.D. geothermalis possesses no flagella or pili for attachment (11) and does not produce large amounts of slime. Bacteria of the genus Deinococcus, including the well-studied D. radiodurans, are known to be highly resistant towards radiation and desiccation (18). According to Makarova et al. (18), it is likely that the extreme radiation resistance evolved in response to chronic exposure to nonradioactive forms of DNA damage, readily inflicted by, e.g., nonstatic environments such as cycles of desiccation and hydration. Such conditions often prevail in biofilms near the air-water interface. Orthologs of almost all known genes involved in different stress responses in other bacteria are present in D. radiodurans (18). All of these properties can contribute to the potential of D. geothermalis for biofouling. We investigated the s...

The combination of an atomic force microscope (AFM) with a Confocal Raman Microscope (CRM) has been used to study the composition of various thin films of polymer blends. The high spatial resolution of the AFM enables the morphological characterization of the polymer blends on the nanometer scale. Furthermore, when operating the AFM in Digital Pulsed Force Mode (DPFM), topographic information and local stiffness can be simultaneously recorded. This allows the material‐sensitive characterization of heterogeneous materials. Thin films where PMMA (at room temperature a glassy polymer) is blended with two different styrene‐butadiene rubbers are investigated. The presence of PMMA in both phase‐separated thin films allows the comparison of the mechanical properties of the two different rubber phases using DPFM‐AFM. When PMMA is blended with PET due to their similar mechanical properties (both are in the glassy state at room temperature) the assignment of the two phases to the corresponding polymers by AFM is rather difficult. Here, Raman spectroscopy provides additional information on the chemical composition of materials. In combination with a confocal microscope, the spatial distribution of the various phases can be determined with a resolution down to 200 nm. Therefore, the topographically different structures observed in AFM images can be associated to the chemical composition by using the Confocal Raman Microscope (CRM).

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We present a comparative microscopic and spectroscopic study of the morphology and composition of WO 3 and W 0.95 Ti 0.05 O 3 thin films, grown by radio-frequency magnetron reactive sputtering at substrate temperatures varied from room temperature to 500°C, using atomic force microscopy (AFM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). With increasing growth temperature, the AFM results show increase in the average crystallite size and in the surface roughness for both undoped and doped samples. The AFM data, along with the Raman results, clearly indicate that for the given set of experimental conditions, higher growth temperatures are required to obtain crystalline Ti-doped WO 3 films than for WO 3 films. Also, the Raman results suggest a potential phase transformation from a monoclinic WO 3 structure to an orthorhombic, but more probably a tetragonal, configuration in the W 0.95 Ti 0.05 O 3 thin films. This remark is based on the observed shifting, with Ti doping, to lower frequencies of the Raman peaks corresponding to W-O-W stretching modes of WO 3 at 806 and 711 cm -1 to 793 and 690 cm -1 , respectively. XPS data indicate that the doped material has a reduced WO 3-x stoichiometry at the surface, with the presence of W 6? and W 5? oxidation states; this observation could also be related to the existence of a different structural phase of this material, corroborating with the Raman measurements.

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