Characterizing how size distribution and concentration affect echogenicity of ultrasound contrast agents

Intraluminal Contrast-Enhanced Ultrasonography Application in Dogs and Cats

Administering intraluminal fluid can improve the acoustic window for the visualization of the lumen and wall layers in the cavitary organs. Microbubbles in ultrasound contrast agents can also be used for intracavitary applications to enhance visualization of the lesion in human patients. However, there was no literature extending the clinical application of intraluminal contrast-enhanced ultrasonography (CEUS) to patients with naturally occurring diseases in veterinary medicine. This case series aims to describe the detailed application and diagnostic value of intraluminal CEUS in six clinical cases with naturally occurring gastrointestinal (GI) and urinary tract diseases.

Construction of a Tumor-Targeting Nanobubble with Multiple Scattering Interfaces and its Enhancement of Ultrasound Imaging

Introduction

Recently, nanobubbles (NBs) have gained significant traction in the field of tumor diagnosis and treatment owing to their distinctive advantages. However, the application of NBs is limited due to their restricted size and singular reflection section, resulting in low ultrasonic reflection.

Methods

We synthesized a nano-scale ultrasound contrast agent (IR783-SiO2NPs@NB) by encapsulating SiO2 nanoparticles in an IR783-labeled lipid shell using an improved film hydration method. We characterized its physicochemical properties, examined its microscopic morphology, evaluated its stability and cytotoxicity, and assessed its contrast-enhanced ultrasound imaging capability both in vitro and in vivo.

Results

The results show that IR783-SiO2NPs@NB had a "donut-type" composite microstructure, exhibited uniform particle size distribution (637.2 ± 86.4 nm), demonstrated excellent stability (30 min), high biocompatibility, remarkable tumor specific binding efficiency (99.78%), and an exceptional contrast-enhanced ultrasound imaging capability.

Conclusion

Our newly developed multiple scattering NBs with tumor targeting capacity have excellent contrast-enhanced imaging capability, and they show relatively long contrast enhancement duration in solid tumors, thus providing a new approach to the structural design of NBs.

Microbubble Biointerfacing by Regulation of the Platelet Membrane Surfactant Activity at the Gas-Liquid Interface for Acute Thrombosis Targeting

Biointerfacing nanomaterials with cell membranes has been successful in the functionalization of nanoparticles or nanovesicles, but microbubble functionalization remains challenging due to the unique conformation of the lipid monolayer structure at the gas-liquid interface that provides insufficient surfactant activity. Here, we describe a strategy to rationally regulate the surfactant activity of platelet membrane vesicles by adjusting the ratio of proteins to lipids through fusion with synthetic phospholipids (i.e., liposomes). A "platesome" with the optimized protein-to-lipid ratio can be assembled at the gas-liquid interface in the same manner as pulmonary surfactants to stabilize a microsized gas bubble. Platesome microbubbles (PMBs) inherited 61.4 % of the platelet membrane vesicle proteins and maintained the active conformation of integrin αIIbβ3 without the talin 1 for fibrin binding. We demonstrated that the PMBs had good stability, long circulation, and superior functionality both in vitro and in vivo. Moreover, by molecular ultrasound imaging, the PMBs provide up to 11.8 dB of ultrasound signal-to-noise ratio enhancement for discriminating between acute and chronic thrombi. This surface tension regulating strategy may provide a paradigm for biointerfacing microbubbles with cell membranes, offering a potential new approach for the construction of molecular ultrasound contrast agents for the diagnosis of different diseases.