The main focus of the lab that I am working in is the development of an ultrasmall (<10nm) non-toxic fluorescent core-shell, silica nano-particle for theranostic purposes. This nanoparticle is composed of a near infrared (NIR) dye encapsulated into a silica core-shell nanoparticle coated with methoxy-terminated polyethylene glycol (PEG) chains to which different biological ligands are attached. One such attached particle is the cyclic arginine–glycine–aspartic acid and tyrosine (cRGDY) peptide, a ligand of ανβ3 integrin receptor or alpha-Melanocyte Stimulating Hormone (MSH), a ligand of the melanocortin receptor (MCR-1). One aspect of research interest in the lab is to characterize the biological properties of this nano-particle on the molecular and cellular level on several cancer cell lines, such as melanoma, glioma and endothelial cells. We are also interested in revealing the behavior of this particle in vivo in terms of pharmacokinetics and bio distribution studies in orthotopic and xenograft models of melanoma or glioblstoma as well as other tumor models. Understanding the behavior of these nanoparticles in vitro and in vivo assists us in translating this multimodal nano particle into diagnostic (optical imaging/Positron Emission Tomography-PET) and therapeutic purposes such as delivery of a drug to the tumor area.