Ultrasound Imaging of Macrophages Intracellularly Labelled with Biosynthetic Gas Vesicles

This study aimed to develop a novel method for real-time imaging to track macrophages and to make it possible to visually track their dynamic features.

The archaeon Halobacterium NRC-1 was cultured in an ATCC medium. Buoyant cells were allowed to produce biosynthetic gas vesicles (GVs), and isolated GVs were collected after lysis. Gas vesicle-labelled macrophages (GV@RAWs) were obtained by incubating macrophage (RAW 264.7) cells with GVs. The ability of GV@RAWs to track macrophages in real-time for a long term was assessed using a high-frequency ultrasound imaging system.

We successfully synthesised and isolated GV@RAWs by co-incubating them with RAW 264.7. The results showed that GV@RAW produced significant ultrasound signals without affecting cell survival and could achieve real-time imaging for up to 3 days in vitro.

This research provides a new way to achieve long-term real-time imaging of macrophages, opening up new possibilities for immune response research, clinical diagnosis and therapeutic strategies for inflammatory diseases.