The Contracting Authority invites tenders for the procurement of one (1) particle counter. The instrument will be used to characterise extracellular vesicles (EVs, lipid nanovesicles and other nanoparticles), including measurement of particle concentration, size distribution and zeta potential, in accordance with the MISEV2023 guidelines. The instrument will also be used for phenotypic quantification by fluorescence (lasers: 488 nm + 640 nm), including colocalisation. The instrument will be in daily use, with a volume of at least 50–70 individual measurements per week. In addition, tenderers shall offer the following options for equipment, service agreements and service: One (1) 405 nm laser delivered and installed together with the instrument. One (1) 405 nm laser retrofitted after installation. Five (5) licences for offline data analysis. Service agreements and service The equipment shall be delivered and installed at the Life Sciences Building (Livsvitenskapsbygget, LVB), room 02.05.238. Oslo University Hospital (Oslo universitetssykehus HF) takes over the building on 15 December 2026, and delivery cannot take place before this date. The delivery date will be specified in the Order. Customers: Oslo University Hospital (Oslo universitetssykehus HF) and South-Eastern Norway Regional Health Authority (Helse Sør-Øst RHF).