The RGD peptide is a popular peptide targeting motif used in experimental, nanoscale drug delivery vehicles (such as liposomes, micelles, dendrimers, nanoparticles, etc.) The RGD peptide binds specifically with cell adhesion molecules on the cell surface. Upregulation/overexpression of cell surface markers (such as this integrin) on certain kinds of cancer cells leads to selective accumulation of nanomaterial drug carriers within cancerous tissues, and targeted delivery of their payloads (drugs, contrast agents for imaging, etc.). Shown is the cyclic analogue of the RGD peptide complexed with alpha 5 Integrin.