| Start Date: | 2/2/2016 | Start Time: | 10:30 AM |
| End Date: | 2/2/2016 | End Time: | 12:30 PM |
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Event Description
BIOMED PhD Thesis Defense
Title: Theranostic Nanoparticles and Drug Loaded Contrast Agents and Their Biomedical Applications
Speaker: Nutte Teraphongphom, PhD candidate, School of Biomedical Engineering, Science and Health Systems
Advisor: Margaret Wheatley, PhD, John M. Reid Professor, School of Biomedical Engineering, Science and Health Systems
Ultrasound contrast agents are typically microbubbles (MB) with a gas core that is stabilized by a shell made of lipids, proteins, or polymers. The high impedance mismatch between the gas core and an aqueous environment produces strong contrast in ultrasound (US). Poly(lactic acid) (PLA) MB, previously developed in our laboratory, have been shown to be highly echogenic both in vitro and in vivo. In the recent years, MB have established their role in contrast enhanced medical imaging and bio-nanotechnology. We show that these microbubble demontrated potential in various applications including multimodal imaging and as a targeted drug delivery vehicle.
Combining US with other imaging modalities such as fluorescence, magnetic resonance imaging (MRI), or computerized tomography (CT) could improve the accuracy of many US applications and provide more comprehensive diagnostic information. Furthermore, our MB have the capacity to house a drug in the PLA shell and create drug-loaded nano fragments in situ when passing through an ultrasound beam. The nano-sized fragments can be taken up into the tumor via the Enhanced Permeability and Retention (EPR) effect. To create multimodal contrast agents, we hypothesized that the polymer shell of our PLA MB platform could accommodate additional payloads. In this study, we therefore modified our current MB by encapsulating imaging-related nanoparticles including aqueous or organic quantum dots (QD), magnetic iron oxide nanoparticles (MNP), or gold nanoparticles (AuNP) to create bimodality platforms in a manner that minimally compromised the performance of each individual imaging technique.
Controlled drug drug delivery system using microbubbles as vehicle in conjunction with ultrasound have been previously studied to reduce drug dosage, systemic toxicity, and side effects for treatment of cancer. To enhance more loading of drug on the MB for a more effective treatment, nanoparticles conjugated with drugs on the surface were used in the study. Nanopaticles are here used to take advantage of the increased surface area per volume ratio for the cancer drug to conjugate on the surface. These drug conjugated nanoaprticles have then been encapsulated inside the MB shell. AuNP and MNP were used in the study of drug delivery.
The DOX-AuNP + DOX MB showed significantly higher loading than loading by the method that was previously developed in our lab, DOX-MB with drug payload ( 43.7 vs. 16.23 µg DOX / mg MB) and encpasulation effiency (48.5% vs. 22.1%). The agents achieved 19 dB of US contrast enhancement in vitro and are shown to provide visible contrast using clinical ultrasound machines. The agent also shown to be able to sustain release of DOX for more than period of 1 week, as well as to form nano polymer fragments (n-Sh) after being insonated for 20 minutes.
In vitro tumoridical activity shown by these agents shown to be effective to both human breast cancer cell line (MDA-MB-231) and hepatoma cancer cell line (Huh7). DOX-AuNP + DOX MB also shown on Opticell system that the plaform can trigger cell death and caused cell lysis within 12 hours after treatment.
This work brings together the advantages of multimodal imaging and drug delivery platforms to significant improve outcomes in cancer diagnostic and treatment.
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Location:
Bossone Research Enterprise Center, Room 302, located at 32nd and Market Streets. |
Audience:
Undergraduate StudentsGraduate StudentsFacultyStaff |
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