This is a Notice of Intent for a sole-source, firm-fixed-price purchase order to Cytek Biosciences Inc. for on-site service maintenance and repair of a Cytek Aurora flow cytometer, with no substitutions possible. The required services include OEM Field Service Engineer preventive maintenance, hardware diagnostics, emergency repairs, and Technical Applications Specialist support for assay optimization, panel design, and troubleshooting. This maintenance supports ongoing NIH research on HIV-1 envelope glycoprotein structure-function and T cell/B cell studies, including experiments begun before January 20, 2025, that relate to HIV envelope protein production for vaccine use and patient samples. Only one award will be made, and the Government plans to issue the purchase order within five days after this notice closes. Qualified responsible sources may submit capability statements to the contracting officer and acquisition specialist for consideration, with the Government retaining discretion on whether to compete the requirement.