Boosting Confocal Microscopes by Quantum Image Scanning Microscopy

The goal of the QuISM project is to develop an add-on module for confocal microscopes which will enhance the spatial resolution of the microscope by up to a factor of 4 and provide quantitative fluorescence imaging, taking advantage of the Quantum-assisted Image Scanning Confocal method recently developed within the frame of the ColloQuantO ERC-CoG project.Image-scanning confocal microscopes (ISM), proposed several decades ago and demonstrated for the first time in 2010 are already a commercial reality (led by the Zeiss ""Airyscan"" system).

Our recently developed method takes advantage of the inherent quantum properties of fluorescence emission to achieve an up to a 2-fold improvement of resolution in ISM without compromising any of the advantageous properties of the standard ISM system.

The only significant hardware changes required for QuISM are the operation of the detector in single-photon counting (“Geiger”) mode and the addition of an electronic correlator element which performs preliminary data analysis on the readout of the stream of photons from the detector array.

Within this configuration, “standard” ISM data is readily obtained even when a microscope is operated in QuISM mode.The QuISM project will set the basis for commercializing QuISM by substantiating the already commercialized CMOScompatible single photon avalanche photodiode array detectors are suitable for this method, proving that the method is applicable for conventional fluorophores used in biology experiments, as well as by developing proper image analysis tools which can fully exploit the potantial of QuISM in terms of acquisition time and quantitative assessment of samples.