Gas vesicles (GVs) are air-filled protein nanostructures (∼85 nm diameter, ∼500 nm length) with the physical property to scatter sound. This new class of contrast agent serves as an acoustic analog to green fluorescent proteins and enables ultrasound imaging of cells that have been genetically labelled with GVs. To date, methods to produce GVs rely on expensive CO ₂ shakers, limiting accessibility and scalability. In this study, we present a cost-effective and scalable protocol to produce GVs using an adapted bubble column photobioreactor design. This production method operates at approximately 10% of the cost of the state-of-the-art, while utilizing off-the-shelf components for broader accessibility and dissemination. We characterized GVs produced with both photobioreactor and shaker-incubator production methods using hydrostatic collapse pressure measurements, hydrodynamic diameter measurements, and ultrasound imaging. Our results demonstrate that GVs produced with both methods exhibit identical physicochemical properties, ensuring intercompatibility. In summary, this new protocol to produce GVs lowers the barrier to producing GVs in research labs, thereby creating the possibility of a broader use of GVs as ultrasound contrast agents and biosensors for a wide array of biomedical applications.
The introduction of genetically encoded gas vesicles (GVs), protein nanostructures with the ability to scatter sound, has created the possibility for deep tissue cellular imaging. GVs establish a platform for biomolecular engineering and were successfully repurposed into acoustic reporter genes and acoustic biosensors. Alongside molecular engineering developments, a method called cross amplitude modulation (xAM) has emerged as the gold standard for non-destructive ultrasound imaging of GVs thanks to its sensitivity and specificity in living biological tissues. Here, we present latest xAM theory and imaging principles. Specifically, we report 1) analytical expressions for the X-wave beam width and primary-to-secondary lobes distance; 2) experimental observations of nondiffractive xAM beams; 3) a method to modulate the secondary lobe level of xAM beams; 4) a demonstration of the incoherent nature of the xAM image noise that can be leverage to increase sensitivity through frame averaging, 5) a beamforming formalism to enhance xAM contrast-to-noise ratio without reducing framerate. Ultimately, the rise of the field of Biomolecular Ultrasound will rest on the co-development of genetically encoded probes and dedicated imaging methods such as xAM and its 3D extension, nonlinear sound-sheet microscopy.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：