A biosensor chip is developed for the detection of a protein biomarker of endocrine disrupting compounds, vitellogenin (Vg) in aquatic environment. The sensor chip is fabricated by immobilizing anti-Vg antibody on 4-Aminothiophenol (4-ATP) coated nanosculptured thin films (nSTFs) of silver on Si substrates. The biosensor is based on the SERS of 4-ATP, enhanced by the Ag nSTFs. Before the fabrication of the sensor, the performance of the enhancement is optimized with respect to the porosity of nSTFs. Further, the biosensor is developed on the nSTF with optimized enhancement. The SERS signals are recorded from the sensor chip for varying concentrations of Vg. A control experiment is performed on another similar protein Fetuin to confirm the specificity of the sensor. The repeatability and reusability of the sensor, along with its shelf life are also checked. The limit of detection of the sensor is found to be 5 pg mL −1 of Vg in PBS within our experimental window. Apart from high sensitivity, specificity and reusability, the present sensor provides additional advantages of miniaturization, requirement of very small volumes of the analyte solution (15 μL) and fast response as compared to conventional techniques e.g., ELISA, as its response time is less than 3 minutes.

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A nanobiosensor chip, utilizing surface enhanced Raman spectroscopy (SERS) on nanosculptured thin films (nSTFs) of silver, was shown to detect Escherichia coli (E. coli) bacteria down to the concentration level of a single bacterium. The sensor utilizes highly enhanced plasmonic nSTFs of silver on a silicon platform for the enhancement of Raman bands as checked with adsorbed 4-aminothiophenol molecules. T-4 bacteriophages were immobilized on the aforementioned surface of the chip for the specific capture of target E. coli bacteria. To demonstrate that no significant non-specific immobilization of other bacteria occurs, three different, additional bacterial strains, Chromobacterium violaceum, Paracoccus denitrificans and Pseudomonas aeruginosa were used. Furthermore, experiments performed on an additional strain of E. coli to address the specificity and reusability of the sensor showed that the sensor operates for different strains of E. coli and is reusable. Time resolved phase contrast microscopy of the E. coli-T4 bacteriophage chip was performed to study its interaction with bacteria over time. Results showed that the present sensor performs a fast, accurate and stable detection of E. coli with ultra-small concentrations of bacteria down to the level of a single bacterium in 10 μl volume of the sample.

The critical strain εc for crazing of polystyrene in each of a variety of organic liquids has been measured along with the degree of swelling of the polymer by the liquid and the attendant reduction in the glass transition temperature Tg of the polymer. The critical strain for the crazing in air and the Tg of each of a set of specimens molded from mixtures of o‐dichlorobenzene and polystyrene have also been determined. Correlations of εc with Tg in the two cases are identical within experimental error for the first 40°C of Tg reduction; these results imply (1) that organic liquids do not exercise a significant surface energy role in solvent crazing and (2) that their only roles are associated with flow processes. Correlation of solvent crazing εc with solubility parameter of the crazing fluid is very poor for several reasons that are discussed.

Physical vapor deposition is a fundamental tool to create thin films for countless applications. Deposition at oblique vapor incidence angles can lead to the growth of thin films with dramatically changed morphological features. Techniques such as oblique angle deposition (OAD) and glancing angle deposition (GLAD) utilize this fact to create self-organized nanostructures on surfaces. The changed columnar microstructure of such thin films significantly influences the film properties. The film density, for instance, influences the refractive index and therefore has impact for optical applications, like filters or antireflection coatings. Understanding the influence of the incidence angle in physical vapor deposition is an important step that allows tailoring the nanostructured surfaces for specific applications not only in optics, but also for catalysis or biosensing usage. To investigate thin film growth at oblique deposition conditions, silicon, germanium, and molybdenum nanostructured thin films were deposited at different angles of incidence by electron beam evaporation. Additionally, a 3D ballistic off-lattice simulation was applied to understand self-shadowing and growth competition, which are the crucial mechanisms for the self-organized growth of nanostructures under oblique particle incidence. On the basis of the observations, a model is proposed that allows the acquisition of accurate predictions for the growth rate and density of obliquely deposited thin films. Special attention is paid to the tilt angle of the columnar film morphology, as it has been under discussion for decades. The developed model predicts the tilt angles for the grown thin films accurately over the complete angle of incidence range. In the model, material properties and deposition conditions are combined into a single parameter, the fan angle. Since perfectly normal deposition is an idealized case, the observed results have an impact on nearly all applications that utilize thin films grown by physical vapor deposition.