Flow cytometer for a dilution-free measurement approach with sample recollection

Blood testing using flow cytometry is a common and rapid method for the initial screening and diagnosis of patients. Measurements are often combined with other scientific techniques, and analyzed samples are commonly diluted and discarded afterward. When the sample is recollected instead, sample dilution is a challenge when the sample is intended or needed for additional measurements. Therefore, it is advantageous to recollect the undiluted sample. In order to enable measurements of the same undiluted sample aliquot, we designed and constructed a purpose-built flow cytometer. Our instrument employs syringes, acoustic focusing, and an open fluidics system to recollect and reuse the unadulterated sample. The cytometer is compact, which reduces sample consumption. It acquires forward, sideward, and fluorescence signals, offering opportunities for diverse measurement approaches. In particular, our cytometer has been designed to be ready for additional downstream analysis of cells, e.g., applying mass spectrometry, magnetic resonance spectroscopy, or other analytical tools. This study presents results on instrument performance, a comparison with a cytometer that uses standard hydrodynamic focusing, and a proof of concept for multiple measurements.