Flow cytometry is a mature technology: Instruments recognizable as having elements of modern flow cytometers date back at least 30 years. There are many good sources for information about the essential features of flow cytometers, how they operate, and how they have been used. For the purposes of this book, it is necessary to know that flow cytometers have fluidic, optical, electronic, computational, and mechanical features. The main function of the fluidic components is to use hydrodynamic focusing to create a stable particle stream in which particles are aligned in single file within a sheath stream, so that the particles can be analyzed and sorted. The main functions of the optical components are to allow the particles to be illuminated by one or more lasers or other light sources and to allow scattered light as well as multiple fluorescence signals to be resolved and be routed to individual detectors. The electronics coordinate these functions, from the acquisition of the signals (pulse collection, pulse analysis, triggering, time delay, data, gating, detector control) to forming and charging individual droplets, and to making sort decisions. The computational components are directed at postacquisition data display and analysis, analysis of multivariate populations and multiplexing assays, and calibration and analysis of time-dependent cell or reaction phenomena. Mechanical components are now being integrated with flow cytometers to handle plates of samples and to coordinate automation such as the movement of a cloning tray with the collection of the droplets. The reader is directed to a concise description of these processes in Robinson’s article in the Encyclopedia of Biomaterials and Biomedical Engineering. This book was conceived of to provide a perspective on the future of flow cytometry, and particularly its application to biotechnology. It attempts to answer the question I heard repeatedly, especially during my association with the National Institutes of Health–funded National Flow Cytometry Resource at Los Alamos National Laboratory: What is the potential for innovation in flow cytometer design and application? This volume brings together those approaches that identify the unique contributions of flow cytometry to the modern world of biotechnology.
Detection of silver nanoparticles in cells by flow cytometry using light scatter and far-red fluorescence
