Table 1.

Method	Description	Strengths and weaknesses
Free-flow electrophoresis	Subcellular components (often pre-fractionated by centrifugation) are flowed through a perpendicular electric field, which separates components into different flow laminae based on their individual electrophoretic mobilities.	High selectivity for many organelle types Appropriate for preparative scale separation Viability of organelles maintained
Alteration in buoyant density	Plasma membranes are treated with dilute detergent (lysis detergent such as Digitonin), thus decreasing their density, prior to density gradient centrifugation. Phagocytosis (ingestion and encapsulation into membrane-bound structures called phagosomes) of latex beads causes phagosomes to float in a sucrose gradient.	Simple and selective yet limited to a few specific organelles
Fluorescence-activated organelle sorting (FAOS)	Derived from fluorescence-activated cell sorting (FACS), subcellular components are labeled with organelle-specific fluorescent antibodies and flowed passed a detector. Fluorescent events trigger sorting of labeled organelles into a collection stream. The collection stream may be integrated to instrumentation or a microwell plate for downstream analysis.	Highly selective and rapid (kHz) Provides the means to measure several characteristics of each subcellular particle Maintains viability although some organelles may be damaged by shear stress Requires special instrumentation
Immunoaffinity purification	A solid support or beads* are modified with an antibody specific to an antigen at the surface of the organelle of interest allowing its extraction from cell homogenate or pre-fractionated organelles. The captured organelle fraction is washed to remove non-specifically adsorbed components, and then the antibody-antigen interaction is interrupted to recover the purified fraction. *In the case of magnetic beads, the beads are exposed to cell homogenate and then extracted magnetically onto a solid support.	Highly selective Gentle, maintaining viability Low capacity for retained material Relatively expensive due to reagent costs