Cell Penetrating Peptide Conjugated BF2-Oxasmaragdyrins as NIRF Imaging and Photo-Thermal Agents.

Laxman, Kandala; Reddy, B Pradeep K; Robinson, Andrea; Srivastava, Rohit; Ravikanth, Mangalampalli

Cell Penetrating Peptides (CPPs) are excellent cell internalizing agents for hydrophobic drug/dye moieties. We exploited this property of CPPs for cell internalization of BF2-oxasmaragdyrin by constructing covalent conjugates of BF2-oxasmaragdyrin with CPPs (CRGDK and polyarginine (R9)) using solid phase peptide synthesis (SPPS) methodology. The CPP-conjugated BF2-oxasmaragdyrins were purified by reverse phase HPLC and characterized by mass spectrometry. The CPP-conjugated BF2-oxasmaragdyrins were found to be photostable, absorb in Vis-NIR region (400-700 nm), emit in the NIR-I region (~715-720 nm) with moderate quantum yields, and possess biocompatibility with excellent cellular imaging potential in breast cancer cells (MDA-MB-231). R9-conjugate being first water soluble BF2-oxasmaragdyrin, also possesses excellent photothermal transduction efficacy with 750 nm laser irradiation and is a potential theranostic agent.