This proposal aims to design a very novel delivery system involving rosette nanotubes (self-assembling guanine-cytosine dimers) covalently linked to a microRNA to target breast cancer cells, and within the nanotube will be a cytotoxic drug such as paclitaxel or tamoxifen. Also linked to the nanotube will be an RGD peptide motif that will act as a directing beacon to tumor cells that typically have up-regulated cell surface proteins that bind the RGD motif (i.e. integrins and CD44). The clinical relevance is obvious: i) targeted delivery to cancer cells (although this reviewer believes that other cells will likewise be targeted by the RGD domain), ii) delivery of a microRNA that can be specific to breast cancer progression/biology, and iii) the ability to more efficiently deliver very hydrophobic molecules such as paclitaxel or tamoxifen. The PI’s also propose to generate a biometric nano bone scaffolding matrix, using a 3D printer, for testing the ability of their nanotube delivery system to inhibit breast cancer cell metastasis to the biometric material -- in essence they will develop an in vitro model of bone metastasis.