Part no fb590 10

QPI was performed using a quadriwave lateral shearing interferometer (SID4-Bio, Phasics, France) [7 (link)] directly attached to the camera port of an Axiovert 200 M inverted microscope (Carl Zeiss Microscopy, Thornwood, NY) with motorized condenser (Part No. 1005-848). The initial evaluation of microsphere and mounting media combinations was performed using an incoherent white light source (HAL 100; Carl Zeiss Microscopy) configured for Kohler illumination through a 590 nm notch filter (Part No. FB590-10; Thor Labs, Newton, NJ). Subsequent evaluation of sensitivity of QPI acquisition settings and cells was performed using a 590 nm centered LED (Part No. M590L3-C4; Thor Labs) for illumination. Images were collected using either a 10X Plan-Apochromat 0.45 NA air objective (Part No. 420640-9900-000; Carl Zeiss Microscopy) or 40X 0.75 NA air objective (Part No. 440350-9903-000; Carl Zeiss Microscopy, Thornwood, New York). Images were acquired using the SID4-Bio acquisition software driving Micro-Manager via a plugin interface [14 (link)]. A reference image of the background media, required for this QPI imaging system, was also acquired. The subsequent sample images were recorded as optical pathlength difference (OPD) in nanometer units relative to the background sample.