Technology
Our products are powered by a form of computational imaging that we call The Phasefocus Virtual Lens™. The patented technology is a novel method for generating high-contast quantitative images and microscopy. It is known in the scientific literature as “ptychography” and is a form of Quantitative Phase Imaging (QPI).
Watch the video below to learn more about our core technology:
Ptychography works equally well in transmitted light and reflected light applications and, given suitable illumination sources and detectors, it can operate using any wavelength in the electromagnetic spectrum, as well electron and other particle waves and even sound waves.
Our flagship product, Livecyte, uses our powerful imaging techology to produce high-contrast videos of live cells without the need for fluorescent labels or high-power illumination. This makes it possible to monitor even the most sensitive live cells, such as stem cells and heterogeneous primary cancer cells, for long periods of time (up to multiple weeks) in a 96-well plate format.
QPI vs Phase Contrast
Quantitative phase imaging (QPI) is often confused with Phase Contrast imaging. Whilst the two techniques have similar names, the possibilities they offer are worlds apart as our CEO Dr. Martin Humphry explains in this short video:
Unlike conventional phase contrast images, videos generated by Livecyte are ideal for downstream image analysis because cells appear as bright features on a dark background, similar to fluorescent images. Our integrated image analysis software uses the unique nature of Livecyte’s data to deliver robust automatic segmentation and the continuous tracking of each cell throughout the timelapse. Unlike in population-based techniques, Livecyte can extract the changes in morphology, motion and dry mass of each cell over time. This leads to a fuller characterisation of cell phenotypic properties.
Patents
Phasefocus’s technology is protected by the granted patents which can be found here.
Imaging process
- A specimen is illuminated by a patch of illumination referred to as the ‘probe.’ The probe area is typically much larger than the desired resolution. Its phase and amplitude distribution are automatically computed, and deleterious effects of any non-uniformities in the illumination can therefore be eliminated.[3] Indeed, by ‘spreading out’ the probe in an essentially random fashion, spatial resolution can be substantially increased[4].
- The probe is shifted to a number of approximately known overlapping positions on the specimen. Alternatively, the specimen can be shifted with respect to stationary probe.
- At each position, the transmitted or reflected diffraction pattern is recorded on a standard two-dimensional array detector (e.g. a CCD).
- A proprietary phase retrieval algorithm processes the diffraction patterns to create an image pair from the specimen: an amplitude image and a phase image. The amplitude image is similar to a conventional brightfield microscope image, and is a quantitative map of the specimen’s transmittance or eflectance. The specimen’s phase function is a quantitative measure of the phase delay introduced as the wavefront travels through, or is reflected by, the specimen.
- Depending upon the specimen and the wavelength, the phase data may be used to measure thickness, refractive index, dielectric constant, surface topography, the local magnetic field environment, and other parameters of interest.