Shape Specific, Enzyme-Responsive, Nano-Imprinted Particles for Drug Delivery

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DESCRIPTION (provided by applicant): Nanotechnology is one of the most promising avenues for the development of advanced drug delivery vehicles. Classically, the field has focused on synthesizing nanocarriers based on self assembly or emulsion based concepts. Although significant progress has been made in polymeric or liposomal drug delivery systems, there remain some key fundamental limitations. These include inability to (a) precisely control shape, aspect ratios, size and polydispersity of the nanocarriers and (b) integrate a variety of disease-specific triggered release mechanisms into the nanoparticle design. Our objective is to use top-down, high throughput nanofabrication technology, specifically a modified step and flash imprint lithography (S-FIL) method, to synthesize highly monodisperse polymer nanocarriers of various shapes, sizes and aspect ratios. By incorporating disease-responsive elements (e.g. peptides) directly into the particle matrix we propose to impart enzyme-responsive release properties into these nanocarriers such that drugs or contrast agents are released primarily in response to tumor-associated signals. The specific aims for this two year period are: Aim 1: To develop a high throughput, top-down nano manufacturing process for fabrication of tumor-targeted, enzyme responsive nanocarriers of precise size and geometry (shape or aspect ratio). In this aim, a modified Step and Flash Imprint Lithography (S-FIL) technique will be employed to produce nanometer size particles of various sizes, cross-sectional shapes, and aspect ratios. The basic material for particle synthesis will be polyethylene glycol diacrylates (PEGDA) and the acrylated penta peptide GFLGK (peptide-DA), which is sensitive to lysosomal cysteine proteases (e.g. Cathepsin B). Cathepsin B is highly over expressed in a variety of cancers including non-small cell lung cancer (NSCLC). Aim 2: To evaluate the effects of size, shape, aspect ratios and macromer concentration on (a) in-vitro cellular uptake of imprinted nanocarriers and (b) intracellular release and transfection of model drugs and contrast agents from enzyme-responsive nanoparticles. We hypothesize that particle shapes, aspect ratio as well as nanoscale dimensions should significantly influence the efficiency of particle internalization. In addition, intracellular delivery of the encapsulated drugs as well as transfection efficacy of a model SiRNA drug will be studied using both fibroblast and lung cancer cells. Aim 3: To study bio- distribution of nanoimprinted particles of various size, shapes and aspect ratios in naove as well as tumor bearing animals. A major hypothesis in studying nanoparticles of various cross sectional shapes and aspect ratios is that these geometric parameters might have strong influence on particle transport properties in blood vessels and therefore should have significant impact on particle bio-distribution as well as tumor accumulation efficacy. Collectively these results should provide a strong basis for future studies on the delivery of therapeutic and diagnostic agents in animal models of various cancers. The goal of this two year exploratory project is to develop a nanoimprint lithography method for fabrication of smart drug delivery nanoparticles. This is a unique top down nanofabrication method for particle synthesis. These nanoparticles are designed to have specific size and shape that can influence their bio distribution. In addition the particles would be able to target tumor cells and deliver the cargo (drugs or imaging agents) to the tumor primarily in response to a disease-specific signal, e.g. enzyme up regulation.