TAT peptide is a cell penetrating peptide (GRKKRRQRRRPQ) derived from the trans-activating transcriptional activator (Tat) from HIV-1. TAT peptide (GRKKRRQRRRPQ) functionalized hybrid nanoparticles are also studied due to their combined magnetic enrichment and optical detection for cell separation and rapid cell labelling. A cell viability assay reveals good biocompatibility of these hybrid nanoparticles.