Sensitive measurement of tumor markers somatostatin receptors using an octreotide-directed Pt nano-flakes driven electrochemical sensor

Tumor markers play an important role in the early diagnosis and therapeutic effect monitoring of tumors. An electrochemical biosensor was developed based on multi-branched gold nanoshells (BGSs) and octreotide (OCT) functionalized Pt nano-flakes (PtNFs) modified electrodes, which was used for detection of tumor-specific markers to evaluate tumor cells. Sandwich-type nano-hybrid materials were prepared by layer-by-layer modification. First, reduced graphene oxide (RGO) and BGSs were modified as electronic materials onto glassy carbon electrodes (GCE). This modified electrode has strong electron transfer capability and large electrode surface area. The OCT was then anchored to the surface of BGSs to sensitively detect Somatostatin receptors (SSTRs) on the surface of HeLa cells. In addition, PtNFs were synthesized using a dual-template method, and OCT template on the surface of PtNFs, as an adsorption bioprobe, was used to reduce the H2O2 and amplify the electrochemical signal of biosensor. The proposed biosensor can be applied to the quantitative broad linear range of HeLa cells covering from 10 to 1 x 10(6) cells mL(-1) (R-2 = 0.9998) and the limit of detection (LOD) was 2 cells mL(-1). The experimental results also show that the sensor has good stability, biocompatibility and high selectivity, which has great potential for clinical application.