The TAT peptide (GRKKRRQRRRPQ) is derived from the transactivator of transcription (TAT) of human immunodeficiency virus and is a Cell-penetrating peptides. Cell-penetrating peptides (CPPs) have been used to overcome the lipophilic barrier of the cellular membranes and deliver large molecules and even small particles inside the cell for their biological actions. CPPs are being used to deliver inside cell a large variety of cargoes such as proteins, DNA, antibodies, contrast (imaging) agents, toxins, and nanoparticular drug carriers including liposomes.