The coupling of screen-printing and laser micromachining technology has been used to create a nanovial with "built-in" working and reference electrodes. The volume of the nanovial was calculated to be 7.2 nL using dimensions determined by SEM. The electrochemical nanovial was characterized using the ferri/ferrocyanide redox couple. Cyclic voltammetry and chronoamperometry experiments were performed with electrochemical nanovials utilizing 5% (v/v) glycerin in the solutions and a humidified headspace to control evaporation of the small-volume samples. Chronoamperometry experiments gave results consistent with a diffusion-limited process and revealed a working electrode surface area of 2.6 x 10(4) micron 2. The ultrasmall-volume cells represent a simple, reliable, low-cost approach for the fabrication of complete electrochemical nanovials.

The quantitative determination of proteins in picoliter-volume vials is described. The assay is based on the bioluminescence of the photoprotein aequorin along with photon-counting detection. Using this approach, avidin can be detected at femtomole levels by taking advantage of its inhibitory effect on the bioluminescence signal generated by biotinylated recombinant aequorin. The picoliter vials were fabricated on glass substrates using a laser ablation technique. Parameters that affect the reproducibility of the assay such as the fabrication and calibration of the pipets, the fabrication of the vials, and the composition of the assay solutions were studied.

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A self-contained ion-selective sensing system within a nanoliter-volume vial has been developed by integrating screen printing, laser ablation, and molecular imprinting techniques. Screen printing and laser ablation are used in tandem to fabricate nanoliter-volume vials with carbon and Ag/AgCl ring electrodes embedded in the sidewalls. Using multisweep cyclic voltammetry, the surface of the carbon electrode can be modified with a polypyrrole film. By polymerizing pyrrole in the presence of nitrate, pores complementary to the nitrate anion in size, shape, and charge distribution are formed in the resulting film. Electrochemical cells modified with this nitrate-imprinted polypyrrole film show a near-Nernstian response to nitrate, and excellent reproducibility. The integration of molecular recognition and electrochemical response in the nanoliter vials is demonstrated by the detection of as little as 0.36 ng nitrate in nanoliter-volume samples. The integration of tailored molecular recognition within nanoliter vials via established fabrication and imprinting protocols should result in a number of nanosensor devices with applications in BioMEMS and micro total analysis systems.

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Although considerable work has been done investigating the properties of arrays of magnetic elements, there have been few investigations on the reverse geometry, i.e., an array of nonmagnetic regions defined within a magnetic thin film. The 10 Hz BH loops, 10-500 MHz permeability spectra, and domain patterns of homogeneous, single layer 100 nm radio frequency ͑rf͒ sputtered Ni 81 Fe 19 thin films with arrays of 23-, 50-, and 100-m-diam holes defined by laser ablation were measured. The holes were defined in a grid along the hard and easy axes of the sample. Letting (x,y) represent, respectively, the hole spacing parallel to the easy and hard axes, the point to point spacing of the ablated circular regions was varied from ͑5, 2 mm͒ to ͑0.1, 0.1 mm͒.

An electrodynamic shaker was used to apply a 1-Hz, 1.5-mm-amplitude, in-plane harmonic excitation to a thinfilm gossamer material mounted in an aluminum fixture. Using a two-camera videogrammetric setup that simultaneously imaged the test article at 75 frames per second (per camera), the x, y, and z motion components of two points on the thin film (F1 and F2) as well as of two points on the aluminum holder (R1 and R2) were tracked for a total of 4 s. The in-plane motion components of each tracked point closely corresponded to the excitation provided by the shaker. The presence of modally induced in-plane film deformation was confirmed by tracking the change in distance between points F1 and F2. The standard deviation of the value of the measured distance between these two points was found to be about 57 m. This value was well above the noise floor for this measurement, 11 m, experimentally determined by calculating the standard deviation of the measured distance between points R1 and R2 on the aluminum film holder, which was considered to be rigid and hence was not expected to undergo in-plane deformation.

Electrochemical vials with volumes of 2.6 nL and embedded working and reference electrodes have been fabricated by coupling screen‐printing (thick‐film) technology with excimer laser micromachining. The processing parameters were varied to determine their effect on the resulting nanocell. The fabricated systems were analyzed by resistance measurements, surface profilometry, and SEM. The performance of the electrochemical nanovials was evaluated by cyclic voltammetry using hexaamineruthenium(III) chloride. The current limits of thick‐film fabrication were approached in creating very small nanocells using the methods described. The functioning small volume electrochemical cells gave voltammograms that were either peak‐shaped or sigmoidal. The shape of the voltammogram corresponded to the electrochemical surface area determined by chronoamperometry.