Early Detection of Vulnerable Plaques Using Targeted Biosynthetic Nanobubbles

<b>Objectives:</b> Atherosclerosis is a chronic inflammatory disease characterized by complex pathological mechanisms. Early detection of vulnerable plaques is critical for assessing rupture risk and preventing acute cardiovascular events. Conventional ultrasound contrast agents (UCAs) are limited in their ability to penetrate the vascular wall and unable to provide detailed information on plaque composition and stability. In this study, we developed biosynthetic gas vesicles (GVs) derived from <i>Halobacterium</i> NRC-1 as UCAs for imaging of vulnerable plaques. <b>Methods:</b> These GVs were functionalized with the VHPKQHR peptide (VHP), enabling specific binding to vascular cell adhesion molecule-1 (VCAM-1), a key biomarker of inflammation in atherosclerosis. In vitro evaluation of VHP-GVs was performed through contrast-enhanced ultrasound imaging using agarose gel phantoms and adhesion assays with inflammatory cell models to assess their targeting capability toward VCAM-1. In vivo ultrasound molecular imaging was performed using the Sprague Dawley (SD) rat model of early-stage atherosclerosis in the left common carotid artery to evaluate imaging efficacy. <b>Results:</b> Both in vitro and in vivo experiments demonstrated that VHP-GVs could effectively penetrate the vascular wall into plaques and generate robust ultrasound contrast signals for precise identification of vulnerable regions. <b>Conclusions:</b> This study establishes a promising tool for the early diagnosis and targeted treatment of atherosclerosis, underscoring the translational potential of biosynthetic nanobubbles in clinical practice.