Leica Stellaris 8 DIVE confocal system with Coherent Chameleon Discovery NX Multi-Photon laser and FALCON FLIM. Procurement of the device funded by Wihuri Research Institute (55%), University of Helsinki: HiLIFE and Faculty of Medicine (45%). Justification for the direct purchase. The justification must be based on one of the preconditions mentioned in the procurement act (1397/2016)( 40§, 41§, 110§, 119§). 40§ 2) only a certain supplier can implement the procurement for a technical reason, or for a reason related to protecting an exclusive right; it shall be a further condition that there are no reasonable alternatives or substitute solutions, and that the absence of competition is not due to an artificial narrowing of the terms and conditions of the procurement. We have evaluated the currently available multiphoton microscope platforms suitable for intravital microscopy and identified Leica Stellaris 8 DIVE with FALCON fluorescence lifetime imaging microscopy (FLIM) as the only available system fulfilling our current needs. For our user base with a range of research areas and using a wide variety of methods and models, we require single-photon confocal and multiphoton imaging combined onto a microscope body compatible with a range of tissue adapters for anesthetized/awake live animals, availability of state-of-the-art objective lenses, a combination of fast resonant scanning with high-quality galvanometric scanning, sensitive silicon semiconductor-based detection with photon counting, and laser beam modulation optimizable for deep imaging or higher resolution. Among the systems that meet the above requirements, the Leica Stellaris 8 DIVE is unique in meeting the following requirements: 1. The possibility of fully spectrally adjustable emission filtering for non-descanned detection of multiphoton excitation with the 4Tune system. This allows maximally flexible use of different fluorophores, which is often crucial for live animal use and deep-tissue imaging, and also serves the ongoing development of novel fluorescence tools within the University of Helsinki. The 4Tune system is covered by the following patents: a. U.S.A. patent US10775599B2; granted and in force. b. German utility model DE202016008334U1; registered and in force. c. European patent EP3308210B1; granted and in force in Germany, France and UK. 2. Multiple multiphoton fluorescence lifetime tools for imaging and analysis, without additional hardware and fully integrated into the microscope control software, namely TauSense and FALCON. The TauSense tools enable the usage of lifetime to get additional information from fluorescence imaging, which allows the characterization and separation of overlapping signals, such as autofluorescence or spectrally similar fluorophores, adding to the flexibility for fluorophore use. Especially in combination with spectrally adjustable emission filtering with the 4Tune system, this maximizes the reliable information gained from valuable samples such as live animals. In addition, the FALCON module contains a full fluorescence lifetime imaging toolkit suitable for acquiring and analyzing fluorescence lifetime data for applications such as fluorescence lifetime-based cell state or environmental sensing and molecular interaction measurements. The TauSense and FALCON functionalities are covered by the following patents: a. Patents US10073034B2, CN103105383B, JP6220510B2; in force in U.S.A, China and Japan, respectively. b. European Patent EP2592413B1; in force in Germany, France, UK, Italy, the Netherlands and Switzerland. No other manufacturer is capable of providing a combined single photon/multiphoton microscope system with spectrally flexible detection and integration of fluorescence lifetime imaging information which fulfill the requirements of our research.
