Spectral Configured Bigfoot Sorter for Salk Institute Flow Cytometry Core - Project Summary The Salk Institute for Biological Studies is an independent non-profit institute for basic science research located in La Jolla, CA. Salk research programs include cancer biology, immunology and microbial pathogenesis, aging and regenerative medicine, neuroscience and neurological disorders, and plant biology. Shared resources and technology cores provide critical support for this research. The Flow Cytometry Core provides Institute researchers access to flow cytometry instrumentation. To accommodate increasing demands for sorting, multi- year strategic acquisitions have been implemented, effectively doubling the Core’s sorting instrumentation since 2017 (instruments were added in 2017, 2018 and 2021). At present, all four sorters in the Core are highly utilized. Three sorters are BD Biosciences Influx instruments, which feature jet-in-air fluidic design and high-speed, multi- well plate deposition mechanics. These Influxes have been versatile and dependable workhorses for many Salk projects over many years. Unfortunately, the Influx system has reached the end of its useful life, with the Core’s units being on average ~10 years old. Costly experimental failures, reduced access to technical support, and a lack of solutions for replacement parts have collectively escalated the urgency to migrate to newer technology, in particular as sorting demands at Salk are projected to continue to increase. Additionally, two Influxes do not meet current standards for aerosol containment. The purpose of this grant application is to address an urgent need: to upgrade the Core’s sorting capabilities by acquiring a cutting-edge modern cell sorter. The Core proposes to acquire a Thermo Fisher Spectral Bigfoot (5-laser, 48-fluorescence detectors). The new instrument will supplement current sorting capacity and be invaluable in times of unexpected delays due to technical failure. The Bigfoot is a best-in-class “jet-in-air” type cell sorter and is the only viable option to replace the obsolete jet-in-air Influx systems. No extra accessories are needed: Bigfoot has an integrated Class II biocontainment enclosure, aerosol containment features, and a high-speed multi-well deposition system for plate sorting. The proposed instrument will use a “spectral” configuration that has the 5 common laser lines that are used in Salk phenotyping panels. This 5-laser spectral configuration will allow investigators to make use of previously optimized staining panels and will add powerful “spectral detection” capabilities currently unavailable at Salk. A major advantage of spectral detection capability is that it provides access to fluorophore combinations previously not possible. This in turn allows additional antigens of interest to be easily added to existing panels. Taken together, there are significant cost and time benefits for leveraging spectral detection: more information can be collected from limited, precious samples, thereby accelerating scientific discovery. The Salk Institute has a strong track record of demonstrated commitment to the implementation, support, and long-term management of high-end instrumentation. With the experience and expertise provided by the Salk Flow Cytometry Core, this new instrument will be immediately utilized at a high level, thereby facilitating scientific discovery at the Institute.