Archives—January 2010

Researcher Envisions Many Uses for Small Biosensors

Story by John Gagnon

Picture yourself with an aortic aneurysm, a weak spot in the vessel that bulges outward and is in danger of bursting. Your doctor has fixed it with a stent, which is like sealing off the weak spot and putting in a new, stronger channel. But what if the stent leaks? That’s a problem that Keat Ghee Ong, an assistant professor in the biomedical engineering department, is addressing. He is devising a wireless sensor, the size of a small paper clip, that could be implanted by the stent. “It’s a good, easy and inexpensive way to scan it to make sure there are no leaks,” he says.

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When Nano Meets Bio!

Monday, January 25
218 EERC
3:00 pm

Presenter: Kyung A. Kang, PhD, Department of Chemical Engineering, Professor and Graduate Program Director, University of Louisville

Abstract: Nano-sized particles have properties that are highly beneficial for biomedical applications.  Liposome and some biopolymeric nanoparticles have been already used for drug delivery.  Our group has been interested in developing metal nanoparticles for diagnosing and treating diseases.  A few examples of these nano-entities are listed below.

Optical Contrast Agent for Molecular Sensing. Fluorophores have been used as a signal mediator in biosensing and imaging for a long time.  Gold nanoparticles (GNP) possess high-density surface plasmon polarion fields that can be effectively used to enhance the sensitivity of bio- sensing and imaging.  We have been developing a highly specific, molecular beacon-like optical contrast agent for accurate  cancer detection/diagnosis utilizing the GNP’s ability of fluorescence quenching and enhancement ability.

Nanoparticle Mediated Hyperthermia.  An alternating electromagnetic (AEM) field at an appropriate frequency can heat nano-sized magnetic particles (MNPs) without heating surrounding tissue.  When iron oxide MNPs are used for cancer treatment (hyperthermia) they can guide the heat generated  by the non-invasively applied AEM field specifically to the tumor, minimizing normal tissue damage.  We have studied and designed novel AEM probe configurations for more user-friendly AEM energy application to the human body.

Multi-functional Nanoparticles.  Several metal nanoparticles also provide good contrast for imaging, e.g., iron oxide particles are a good MRI contrast agent and gold particles enhance the contrast of X-ray/CT.  By combining these beneficial features, multi-functional nano-entities can  be developed, enabling seamless disease diagnoses and treatment.

Histotripsy: Imaging Guided Ultrasound Therapy for Non-invasive Surgery

Friday, January 22
130 Fisher
2:00 pm

Presenter: Zhen Xu, PhD, Assistant Professor, Dept. of Biomedical Engineering, University of Michigan

Abstract: Histotripsy is a new non-invasive technique  that mechanically fractionates and removes soft tissue using high intensity ultrasound pulses. By focusing ultrasound pulses to the targeted tissue inside the body, histotripsy produces a cluster of energetic cavitation microbubbles within a treatment region. These microbubbles, each similar in size to individual cells, function as “mini-scalpels” to mechanically fragment and subdivide targeted cell and tissue structures. Meanwhile, the tissue outside the treatment region remains intact. The histotripsy treatment is guided and monitored  by ultrasound imaging  in real-time. Histotripsy has potential for many clinical applications where non-invasive tissue removal is desired. My work focuses on cardiovascular and fetal therapy applications. I will talk about my current projects, including histotripsy for breaking  down diseased blood clots (thrombolysis), creating intracardiac communications for congenital heart diseases, and prenatal therapy.