A novel and versatile tool for the rapid detection and removal of apoptotic and dead cells 3214

Abstract Description Phosphatidylserine (PS) exposure on the outer leaflet of cell membranes is a hallmark of apoptotic cells and plays a critical role in immune clearance and signaling. As an immunosuppressive signal, externalized PS is often exploited by cancer cells and pathogens to evade detection, making it a key target for research into apoptosis and PS-based therapeutic strategies. BioLegend has successfully commercialized Apotracker™ Green, a uniquely designed peptide that incorporates BODIPY. Apotracker Green specifically binds to PS in a calcium-independent manner, offering enhanced versatility over traditional PS detection methods. Building on this innovation, we have developed Apotracker tag, a modified peptide-based probe that retains high-affinity PS binding while allowing flexible conjugation with various tags. Here, we demonstrated that Apotracker tag can rapidly identify apoptotic and dead cells in under 5 minutes without the need for buffer changes or washing steps. Its efficacy is demonstrated across multiple applications, including multicolor flow cytometry, cell sorting, multiplex imaging, fluorescence-based cell counting, and high-throughput screening. Additionally, when combined with magnetic beads, Apotracker tag can be used to efficiently remove apoptotic and dead cells and enrich PS-positive extracellular vesicles. These multiplexed applications in high-throughput settings hold great potential for drug screening and biomarker discovery. Topic Categories Technological Innovations in Immunology (TECH)