Point-of-care protein detection for diagnosis of diseases require low cost techniques,while maintaining minimum sample amounts and operational simplicity,detection sensitivity.Modern commercial immunology detection methods including the Abbot IMX,Hybritech Tandem E and R,Roche Elecsys and ELISA,etc.Here we utilize carbon nanotubes to develop a kind of immunosensor for detecting trace quantities of immune globulin (IgG).Pure samples of single-walled carbon nanotubes(SWCNTs) are obtained by way of chemical vapor deposition(CVD).Briefly,it should be carboxyl-functionalized and shortened by strong acid upon sonication for several hours firstly.The dispersions were filtered,washed,dried,and dispersed in DMF(1mg/ml),then aged for several weeks.GC electrode were polished with 1.0,0.3,0.05μm alumina slurries,and thoroughly rinsed.The GC electrode surface was modificated with Ph-NH2,and immersed into the above dispersed solution for 3h in ambient temperature to forming vertically aligned SWCNTs arrays.We utilized sandwich immunological method,and got electrochemistry signals from the reduction process in which horseradish catalyze H2O2 to decompose.We used bovine serum albumin(BSA) for nonspecific binding.