Abstract: The present invention is directed to a modified graphene structure comprising at least one graphene sheet (1) and a self-assembled monolayer (2) of functional organic molecules (3) non-covalently bonded to the top and/or bottom basal planes of the graphene sheet and methods of manufacture thereof. The present invention is also directed to devices comprising the modified graphene structures, including but not limited to field-effect devices and biosensors, and to methods using the modified graphene structures.

Abstract: Hepatic status of a subject is determined by measuring the level of pi glutathione S-transferase (&pgr;GST) in a biological fluid such as bile or plasma from the subject by an immunoassay. An increased level of &pgr;GST as compared to a normal range of &pgr;GST indicates an abnormal condition of the liver. Measuring &pgr;GST level has particular application for determining the hepatic status of a liver transplant recipient because it enables detecting liver transplant rejection at a very early stage after transplantation. The immunoassay is preferably an enzyme immunoassay, and the entire immunoassay can be completed in 2.5 hours. The biological fluid may be diluted with a diluent which contains an effective amount of a protein such as serum albumin to optimize antibody-antigen reaction. When plasma is the fluid, the plasma should be collected and stored prior to the determination in the presence of an anti-coagulant under conditions which permit substantially no haemolysis.