Exam (elaborations) PSBT104 (PSBT104) Under the Microscope

This document provides a detailed overview of Acoustic Flow Cytometry, an advanced flow cytometric technique that uses ultrasound-based acoustic focusing to precisely align cells or particles within a flow stream. Unlike conventional flow cytometry that relies on hydrodynamic focusing using sheath fluid, acoustic flow cytometry employs standing acoustic waves to position cells at pressure nodes, enabling sheathless or low-sheath operation. The document explains the principle of acoustic focusing, key instrumentation components, and the working mechanism of how cells are focused and interrogated by a laser beam. It highlights how this technology improves signal resolution, sensitivity, and throughput, while reducing sample dilution and shear stress, thereby maintaining better cell viability. Further, the document discusses light scatter and fluorescence detection, including parameters such as forward scatter (FSC), side scatter (SSC), and fluorescence signals detected by photomultiplier tubes (PMTs). A comparison with conventional flow cytometry is included to emphasize the advantages of acoustic focusing. Finally, the document outlines major applications of acoustic flow cytometry in rare cell detection, bacterial and small particle analysis, immunophenotyping, biomedical research, and clinical diagnostics, making it a valuable technique for modern high-performance cell analysis.