Tetragonal ferroelectric BaTiO3 nanoparticles are hydrolyzed inside peptide‐ring templates at room temperature and pressure (see figure). The sizes of the monodisperse BaTiO3 nanoparticles are controlled between 6 and 12 nm by varying the cavity size of the nanorings as a function of pH. The nanoparticles possess switching behavior under the influence of external electric fields.

perature for 10 min. The DTT was removed by extraction with 400 lL ethylacetate. The resulting aqueous solution was diluted to create a 1 lM solution in 1 M potassium phosphate buffer pH 7.0. The DNA linker solution was mixed with a 1 lM solution of 6-mercapto-1-hexanol in 1 M potassium phosphate buffer pH 7.0 at a given molar percentage to give solutions that were 1 lM in total thiol, of which 0, 10, 20 and 100 % of the thiol content was 1. Hereafter, those solutions are denoted as 0 %, 10 %, 20 %, and 100 % solution, respectively.A gold-coated cantilever was immersed in 100 % solution overnight. The cantilever was then rinsed with deionized water and immediately immersed in a 1 lM solution of 6-mercapto-1-hexanol overnight. The cantilever was then rinsed with deionized water and absolute ethanol. A couple of droplets of each co-deposition solution were placed on an individual quadrant of the patterned substrate and kept overnight in 100 % humidity. The 100 % quadrant was rinsed with deionized water and then immersed in a 1 lM solution of 6-mercapto-1-hexanol overnight to backfill the quadrant. The surface was then rinsed with deionized water and ethanol and dried under a flow of nitrogen. For the 100 % quadrant, the surface density of 1 was determined by washing off a fluorescently tagged complementary sequence on an identically treated but larger (2 cm by 2 cm) gold surface.Gold Pattern Height and Unbinding-Force Measurements: Heights of gold patterns were measured in solution at room temperature using tapping-mode AFM (Nanoscope III, Digital Instruments), on which a commercially available Si 3 N 3 cantilever and the immobilized surface were mounted. The force measurements were carried out with the functionalized cantilever (spring constant after thiol immobilization determined to be 0.133 pN m ±1 by thermal fluctuations) [14]. The threshold was set to 10 nm, delay to 0 s, scan rate to 1 Hz, and ramp size to 1 lm. The force measurements were repeated 50±100 times for every set of conditions. In trials, no statistically significant difference in average pull-off force was observed between the first 50 and all 100 measurements. Recently, one-dimensional (1D) single chains of metal nanoparticles (SCMNPs, i.e., nanocrystal necklaces) have been attracting much attention owing to their unique electron-transport properties that arise from coulomb-blockade and quantum-confinement effects.[1±6] The transport properties are sensitive to the size of the nanoparticles and the gap COMMUNICATIONS

The peptide nano-rings containing Au nanoparticles inside their cavities were self-assembled on dithiol SAMs patterned as an array by AFM-based nanolithography. The peptide nano-rings were aligned as a line on these SAMs, and Au formed lines with the spacing between these nanoparticles as the peptide nano-rings functioned as spacers. This type of array fabrication will provide improved tunability in their optical properties of resulting nanoparticle-assembled arrays. In addition, optimization of the inter-particle distance of nanoparticles in the array with various spacers may allow one to design new types of photonic crystals with desired optical properties.