Abstract: Disclosed are an optical interferometry apparatus for detection of dielectric nanoparticles and a method for enhancing visibility of the nanoparticles. An imaging system for detection of dielectric nanoparticles includes at least one light source for illumination, a detector array or a camera for image capture, an objective lens, a sample substrate and a computing unit. The sample substrate is capable of carrying sub-wavelength particles smaller than the diffraction resolution limit of the imaging system, and the imaging system includes a movable means which moves the sample substrate in the axial direction such that depthwise different images are captured at different axial distances from the sample substrate to the objective lens. The computing unit computes a correlation image using the depth images wherein the sub-wavelength particles become resolvable and appear with higher contrast in the correlation image.

Abstract: The present disclosure provides technologies for achieving cell patterning, as well as patterned cell arrays achieved with such technologies. Provided apparatus and methods are useful in a variety of contexts and provide particular advantages with respect to assessing living cell arrays and/or their responsiveness to stimuli, including identifying and/or characterizing complex cellular responses.