An efficient strategy to assemble water soluble histidine-perylene diimide and graphene oxide for the detection of PPi in physiological conditions and in vitro.

A strategy to develop water soluble, biocompatible nanocomposite probe for the detection of pyrophosphate (PPi) in physiological conditions and in in vitro live melanoma cancer cells (B16F10) is reported. The self-assembled nanocomposite probe comprised of amino acid (histidine) functionalized perylenediimide (PDI-HIS), copper ion and graphene oxide (GO) and that could be utilized as a highly effective sensing platform in biological conditions and cellular environment via fluorescence "turn-on" for PPi detection. This controlled fabrication of metal organic self-assembled spheres along with GO proved very valuable for the detection of PPi in unprecedented sensitivity over other competing ions. The PDI-HIS-Cu-GO (PCG) nanocomposite sensor provides a unique platform for the fluorogenic detection of PPi having a very low limit of detection (LOD) of 0.60×10-7M based on the strong affinity (1.0×106M-1) between the copper complex of PDI-HIS receptor and PPi. The intracellular detection of PPi using PCG also carried out in B16F10 cells where >10 times observed as compared to the PDI-HIS+Cu2+ complex. Thus early cancer detection via PPi recognition in physiological conditions and in live cells was possible using PCG. Furthermore, the fabrication of PDI-HIS and PCG with PVA hydrogel films and on thin layer chromatography plates demonstrated the practical utility for the detection of PPi anions by "off-on" response rapidly in a label free manner.