Research

Research

Imaging Reactive Oxygen Species to Detect Oxidative Stress

Objective

Elevated Hydrogen Peroxide (H2O2) levels (>30µM) in tissues is the hallmark of oxidative stress that is implicated in many diseases, including cancer. There is no current method to detect H2O2 in vivo except for optical imaging, which is severely limited by poor penetration. To that end, the goal of this project is to develop an ultrasound-based strategy for in vivo H2O2 detection.fig. 1

Figure 1

fig. 2
Figure 2 

fig. 3
Figure 3

Method

We formulated silica nanoshell particles (NSP) containing catalase, an enzyme that converts H2O2 into O2 and water, and aimed to detect O2 microbubbles with ultrasound. In vitro imaging was performed with a Siemens Sequoia 512 (15L8 transducer). 

Back to Top

Phase-Shift Very Low Boiling Point Nanodroplets

Objective

Acoustic droplet vaporization (ADV) of superheated perfluorocarbon nanodroplets (NDs) demonstrates potential as an extravascular ultrasound contrast agent that may facilitate ultrasound-based therapeutic applications, yet these agents are metastable and difficult to manufacture in high yield. We hypothesized that emulsification optimization and a surfactant/co-surfactant strategy would improve the yield, stability, and shelf-life of these agents.

Figure 1

 

Figure 2

 

Figure 3

Method

Emulsions of perfluorobutane obtained through direct emulsion combined with surfactants and/or co-surfactants were characterized using particle counters and sizers and their acoustic response investigated with a Acuson Sequoia S512 ultrasound system with 15L8 transducer.

Back to Top

Detection of Acute Thrombosis with New Activatable Contrast Agents

Objective

Acute deep vein thrombosis (DVT) is the formation of a blood clot in the deep veins of the body that can lead to fatal pulmonary embolism. Acute DVT is difficult to distinguish from chronic DVT and is therefore treated aggressively with anticoagulants, which can lead to internal bleeding. We aim to develop a contrast agent that detects acute thrombosis with ultrasound imaging.

Figure 1
Figure 2

Method

Acute clotting occurs when thrombin is activated. We are using activatable cell-penetrating peptides (ACPP) composed of a fluorescently-labeled (FITC) polycationic chain and a polyanionic chain that neutralizes the charge. Upon cleavage of the peptide by thrombin, the polyanionic peptide is dissociated, yielding the polycationic-labeled reporter that adheres to cell membranes.

Back to Top