NIR emissive probe for fluorescence turn-on based dead cell sorting and in vivo viscosity mapping in C. elegans

Dead cell sorting is pivotal and plays a very significant role in homeostasis. Apoptosis and ferroptosis are the two major regulatory cell death processes. Apoptosis is a programmed cell death process, while ferroptosis is a regulatory cell death process. Monitoring the dead cells coming out from these processes is extremely important to stop various cellular dysfunctions. Here, we present a single NIR emissive probe that can observe both apoptotic and ferroptosis regulatory cell deaths. We were able to directly visualize the dead cells in both animal and plant cells upon a significant increase in the fluorescence intensity of the probe. During cell death, the increased cytoplasm viscosity restricted the rotor motion and helped in the fluorescence turn-on of the probe. Lysosomal viscosity was found to play a crucial role in the ferroptosis pathway. On the other hand, the probe was not only efficient in mapping the viscosity in various parts of live Caenorhabditis elegans (C. elegans) bodies but also able to differentiate between live and dead animals.