Multifunctional nano scale therapeutics represents a transformative new frontier in disease treatment. Liposomes provide a versatile and dynamic platform for encapsulating functional inorganic nanoparticles with different surface chemistries to achieve multiple therapeutic objectives. This project employs original approaches to selectively decorate engineered liposomes with inorganic nanoparticles, and examine how nanoparticle size, charge and hydrophobicity affect liposome structure and function. Such composite assemblies will play an important role in therapeutic applications where spatially as well as temporally targeted delivery is required. Surface functionalized superparamagnetic iron oxide (SPIO) will be used as model nanoparticles, as they have been successfully employed as MRI contrast agents and for in vivo hyperthermia, where heating is achieved using external magnetic fields operating at radio frequencies. Programmed RF stimulation of the magnetoliposomes will provide a simple yet robust way to control liposome structure and stability. Through Aim 1, electrostatically and hydrophobically assembled decorated magnetoliposomes will be formed and their structure, morphology, and colloidal stability characterized. In Aim 2, the effect of selective decoration, SPIO nanoparticle lipid interactions, and RF-heating on lipid phase behavior will be studied. In Aim 3, selective transbilayer permeability of a molecule encapsulated within the magnetoliposomes will be demonstrated via controlled-release or a novel burst-release mechanism through programmed RF heating.
Intellectual Merit. The ability to selectively control phase behavior, heat, and mass transfer in soft colloidal nanoscale systems is highly desirable for the formation of next generation multifunctional therapies, nanoparticles, nanomaterials, and nanodevices. Localized RF heating in bilayers is an original concept that is expected to provide selective control over bilayer phase behavior, and in turn diffusion. This project will provide new experimental methods for the synthesis and characterization of hybrid nanoparticle/lipid assemblies. Hence, the integration of inorganic nanoparticles and biomolecular systems will be extended to include this unique class of active nanomaterials. Characterizing thermodynamic and transport properties will provide a complete picture of the assemblies, which will be needed to determine their potential as multifunctional therapeutic agents. For instance, the decorated magnetoliposomes may enhance drug delivery by providing an external trigger and yielding time and dose dependent diffusion. By inverting the problem, we also have identified a way to use the magnetoliposomes as a potential nanoscale temperature sensor.
Broader Impacts. Given the minimally invasive nature and tissue penetration of RF-heating, these novel carriers would be very effective for manipulating the delivery of therapeutic agents in vivo. Opportunities are being pursued with faculty from the College of Pharmacy at URI to identify promising applications. In addition, these new structures provide suitable model systems for studying nanoparticle interactions with cellular membranes, including their role in uptake and potential toxicity. This project will also serve as an educational tool for high school, undergraduate, and graduate students. Co-PI Bose organizes a summer high school intern program and both PIs have been contacted by and will work with the New England LSAMP program to mentor students. Within our diverse laboratory groups, we intend to pair high school and undergraduate students with graduate student mentors to conduct independent projects directly related to hybrid liposomes. This activity will expand the impact of the project to beyond the traditional and expected research participation. The concepts behind this project and the results obtained will be used as teaching material in a new interdisciplinary graduate level Bionanotechnology course offered in the spring semester, and disseminated freely through a collaborative website.
Rises in the spread and severity of chronic diseases coupled with the need for selective and safe treatments have created a demand for more effective therapies. In addition to being economical and stability, the ideal therapeutic system would be multifunctional, for example, providing simultaneous diagnostics and drug treatment. The goal of this project was to develop new methods for creating nanometer-scale systems that can be controlled by external stimuli and are capable of multiple therapeutic objectives. Using established liposome technologies, methods were developed that allowed liposomes to be decorated with iron oxide nanoparticles. Iron oxide nanoparticles are used as contrast agents for medical imaging (e.g. MRI) and can be "activated" by alternating electromagnetic fields at radio frequencies (RF). Integrating liposomes with iron oxide nanoparticles yields a structure capable of drug delivery (via the liposomes) that can be controlled by RF fields (iron oxide nanoparticles). Imaging and magnetic guidance is also possible. Because such structures were novel, detailed fundamental characterization was conducted to understand how the structures formed, how they functioned, and how they could be optimized. This was achieved through a variety of techniques in calorimetry, electron microscopy, and spectroscopy. This project was led by Professors Geoffrey D. Bothun (PI) and Arijit Bose (Co-PI) in the Department of Chemical Engineering at the University of Rhode Island (URI), and involved three graduate students and seven undergraduate students. It served as a basis for generating new curriculum related to two nanotechnology-based courses at URI, for hosting workshops and laboratory tours that engaged middle school female students interested in STEM and urban high school students, and for providing advanced training and professional development opportunities. Major outcomes from this project are summarized below. 1. New strategies were developed for integrating different types of functional iron oxide nanoparticles within liposomes. This included "bilayer decoration" and "surface decoration." Analyses showed that these structures could be quite stable, and demonstrated the connection between nanoparticle integration and liposome structure and function. The ability to create such structures provides new routes for designing therapeutic nanostructures, which could improve disease detection and treatment. 2. The feasibility of using physiologicaly non-invasive electromagnetic fields to trigger release was demonstrated using a model small molecule drug encapsulated within the liposomes. The release of this molecule could be controlled through nanoparticle concentration, exposure time, and electromagnetic field strength. Being non-invasive, the ability to trigger release using electromagnetic fields provides a safe treatment option. This is made possibly by the structure of the liposomes. 3. The ability to utilize these liposomes as therapeutic agents was demonstrated in vitro using a hepatocellular carcinoma (liver cancer) cell line. The liposomes were stable and did not release their chemotherapeutic cargo until they were internalized by the carcinoma cells and subjected to an electromagnetic field. 4. The project has involved 3 graduate and 7 undergraduate STEM students. Of the graduate students, 1 is employed as a postdoctoral fellow at URI, 1 is employed by Amgen, and 1 is continuing his doctoral work. Of the undergraduate students, 4 are now enrolled in domestic or international graduate programs, 1 is employed with Rhode Island, and 2 are continuing their undergraduate work.
