A Two-Dimensional Lock-In Algorithm for Signal Analysis in Patterned Images.

Goal: We extend a classic signal processing algorithm, the lock-in amplifier, to two dimensions to extract the signal in patterned images.

Methods: The algorithm was evaluated using simulated image data and experimental microscopy images to determine the fluorescence signal of fluorescently labeled proteins adsorbed on surfaces patterned with chemical vapor deposition.

Results: The algorithm was capable of retrieving the signal with a signal-to-noise ratio as low as -20 dB.

Ultrasensitive In Situ Fluorescence Analysis using Modulated Fluorescence Interference Contrast at Nanostructured Polymer Surfaces.

The precise modulation of fluorescence interference contrast is achieved by introducing a nanoscopically engineered spacer layer prepared by chemical vapor deposition (CVD) of functional polymers. These novel imaging substrates are chemically identical throughout their entire detection area, yet present patterns of nanoscale thickness. A protein binding cascade is studied in real time and in the presence of high background noise.

Programming a Pavlovian-like conditioning circuit in Escherichia coli.

Synthetic genetic circuits are programmed in living cells to perform predetermined cellular functions. However, designing higher-order genetic circuits for sophisticated cellular activities remains a substantial challenge. Here we program a genetic circuit that executes Pavlovian-like conditioning, an archetypical sequential-logic function, in Escherichia coli.

Modeling negative cooperativity in streptavidin adsorption onto biotinylated microtubules.

The nanoscale architecture of binding sites can result in complex binding kinetics. Here, the adsorption of streptavidin and neutravidin to biotinylated microtubules is found to exhibit negative cooperativity due to electrostatic interactions and steric hindrance. This behavior is modeled by a newly developed kinetic analogue of the Fowler-Guggenheim adsorption model.