Our lab develops and investigates the properties of photoacoustic contrast agents based on microbubble and perfluorocarbon droplet platforms. Potential applications of these agents include molecular imaging, tracking of drug-loaded particles, and monitoring the release of drugs from activatable drug carriers.
The photoacoustic response produces acoustic waves from tissue-specific absorption of light energy. Our lab develops and investigates the properties of photoacoustic contrast agents based on microbubble and perfluorocarbon droplet platforms. As shown below, these contrast agents integrate light absorbing nanoparticles, like gold nanorods (AuNR), on their surface and absorb light energy. The resulting photoacoustic responses are significantly larger and carry unique information, which allows them to be differentiated from photoacoustic signals originating from the surrounding tissue.
Dixon et al, Small, 2015
We use high speed cameras to visualize the response of these agents to laser excitation on the nanosecond timescale. As demonstrated in the video, the microbubble expands immediately following laser excitation and relaxes to approximately its original size within 1 microsecond.
Dixon et al, Small, 2015
Potential applications of these agents include molecular imaging, tracking of drug-loaded particles, and monitoring the release of drugs from activatable drug carriers. As an example, in the video below, red blood cells were loaded with light absorbing particles, drugs, and perfluorocarbon nanodroplets. These agents rupture when exposed to high intensity ultrasound, thereby releasing the drug locally and dispersing the light absorbing particles. After their dispersion, they will no longer yield a strong photoacoustic response, thereby confirming rupture of the blood cell and local drug delivery.
Ultrasound molecular imaging is a powerful imaging method which utilizes microbubble contrast agents to target and bind disease markers in the blood vessels. While traditional imaging methods detect disease by gross anatomical features, we aim to detect disease on a molecular level. This unprecedented level of imaging sensitivity can not only improve the contrast and clarity of diagnostic images, but significantly improve patient outcomes as physicians make faster, more accurate diagnoses. In our lab, we program ultrasound imaging sequences and image processing techniques to improve the contrast and isolation of microbubble signals. Our studies work to advance the field of ultrasound molecular imaging toward rapid clinical adoption.
Microbubbles are the most widely used ultrasound contrast agent and can be fabricated in a number of ways, including via sonication, agitation, and microfluidics. Hossack lab studies the use of the microbubbles as imaging contrast agents and as therapeutic agents for drug delivery and sonothrombolysis. We are also investigating the use of this technology in catheter-based applications and are in the process of developing on-chip electrical control and monitoring systems to regulate device operation in real-time.
Our lab develops and investigates the properties of photoacoustic contrast agents based on microbubble and perfluorocarbon droplet platforms. These contrast agents integrate light absorbing nanoparticles, like gold nanorods (AuNR), on their surface and absorb light energy. The resulting photoacoustic responses are significantly larger and carry unique information, which allows them to be differentiated from photoacoustic signals originating from the surrounding tissue. Potential applications of these agents include molecular imaging, tracking of drug-loaded particles, and monitoring the release of drugs from activatable drug carriers.
Echocardiography is frequently used to assess cardiac function. However, getting a diagnostic quality echocardiographic image is often difficult due reflections from the surrounding anatomy and subcutaneous fat. These reflections are super imposed on the moving heart and hinder diagnosis. In the Hossack Lab we develop signal processing methods to eliminate artifacts while retaining the underlying tissue. We confirm that the underlying tissue is retained by wall motion tracking analysis.
