Abstract
CHEMISTRY Chemical patterning of surfaces has traditionally been achieved by zapping a reactive coating with light or electron beams. More recently, “dip pen” techniques have used atomic force microscope (AFM) probes to plant molecules in selected surface locations. Davis et al. show that AFM probes can also be used as spatially selective catalysts. They capped the silicon nitride probe tips with palladium nano-particles, which catalyzed the Suzuki coupling of aryl boronic acids to a layer of aryl bromides that were bound through sulfide linkages to a gold surface. After submerging the film in a methanol solution of the boronic acid and a base, they maneuvered the probe to the desired reaction site and induced coupling by applying 20 to 25 nN of force between tip and surface. Reducing the force to the 1- to 5-nN range allowed imaging of the patterned surface without further catalysis. For verification of spatial selectivity, coupling was performed with amine-substituted boronic acid substrates, which were subsequently labeled with fluorescent dye. — JSY J. Am. Chem. Soc. 10.1021/ja043235+ (2005).
Highlights
Autoimmune conditions, such as type 1 diabetes, are unpredictable and difficult to manage
Improvements in treatment will depend on better noninvasive monitoring of those at risk in order to enable forecasting of disease onset, sensitive and accurate screening for changes in disease status, Pancreatic infiltration and islet histology
In the NOD mouse, magnetic resonance imaging (MRI) measures of increased vascular leakage correlated with diabetes close to the time of disease onset, but were not as useful in longer-range prognosis
Summary
A nanoscale template (for making materials and devices) can be created by coating an array of closely packed particles, but it often is difficult to handle such a film without tearing it, because it is, in essence, a thin ceramic sheet. Wang et al report on the formation of transferable and reusable TiO2 “nanobowl” A nanobowl sheet on a copper grid and a schematic templates. They coated a silicon (inset) of the fabrication. Ion milling removed the top half of the spheres, and the PMMA was dissolved with acetone to free the film from the silicon substrate. The nanobowl film could be freed completely by removing the PS with toluene. These films (as large as 10 mm2) were lifted with a copper mesh support and examined in a transmission electron microscope, which revealed that the bottoms of the TiO2 bowls have a 100-nm opening.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
