The development of a "magic bullet" that could carry a therapeutic dose of drug to a target organ or tumor with high specificity is the ideal goal of targeted drug delivery. The development of such a vehicle could improve therapeutic efficacy while reducing side effects. This is of particular interest for chemotherapy administration, where the drugs have high systemic toxicity. In this proposal, novel microfluidic technology is utilized to precision engineer acoustically-active drug delivery vehicles. Currently, liposomes are utilized as one of the most effective drug carriers, although their in-vivo accumulation is relatively non-specific. We propose that by making acoustically-active liposome-like vehicles, we can overcome this nonspecificity by utilizing ultrasound to "steer" the vehicles using acoustic radiation force and then disrupt the vehicle shells to release the contents preferentially at the target site. Acoustically active drug carriers must possess a layer with drug-carrying capacity, similar as a liposome, yet at the same time, they must have a core with significantly different density and compressibility than the surrounding media - such as a gas. Vehicles with this unique multi-layer composition can be created with microfluidics. Additionally, microfluidics provides a precise way to engineer vehicles with exactly the same size, drug payload, and shell characteristics. The uniform acoustic properties of precision engineered vehicles will allow specific tuning of the ultrasound frequency for optimized acoustically-mediated delivery, and will enhance the ability of these vehicles to be used for simultaneous imaging. This proposal describes a multi step process for the development, improvement, and exploration of acoustically-active drug delivery vehicles for site-specific drug delivery. The first step in this proposal is the precision engineering of acoustically active drug delivery vehicles through the application of novel microfluidic technology. The second component consists of testing and optimizing the stability, acoustic properties, and drug release characteristics of these new vehicles, as well as examining the safety of ultrasound parameters optimized to concentrate and disrupt the vehicles. Finally, the delivery potential and biodistribution of the new vehicles will be examined with optical imaging and ultrasound. This collaboration between the principal investigators at the UNC- NCSU Joint Department of Biomedical Engineering, the UNC School of Pharmacy, and the University of California Irvine provide a unique and qualified research group with expertise in ultrasound, microbubbles, drug delivery vehicles and their drug loading and release characteristics, and microfluidics required to achieve these goals.
PROJECT NARRATIVE Our research proposes to create and test new acoustically-active delivery vehicles for site specific delivery of chemotherapeutics. These vehicles have the potential for local delivery of chemotherapy or other drugs while minimizing systemic toxicity. The success of an acoustically localized delivery system would improve therapeutic methods, reduce side effects, and improve public health.
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