As shown in Fig. 4, the oxidation currents of Fe2+decreased with the biomarkers concentrations increased, and there was a positive correlation between the oxidation peak currents and the concentration of analytes. prediction model based on the six kinds of biomarkers for predicting risk of gastric cancer. In conclusion, the electrochemical microfluidic chip for detecting multiple biomarkers has great potential in applications such as early screening of gastric cancer patients, and therapeutic evaluation, and real-time dynamic monitoring the progress of gastric cancer in near future. Keywords: Electrochemical, Microfluidic chip, Multiple biomarkers, Early diagnosis, Gastric cancer == Background == Gastric cancer (GC) is the second most common cancer and the third leading cause of cancer-related death in China [13]. It remains very difficult to cure effectively, primarily because most patients present with advanced diseases. Up to date, gastric cancer prognosis is very poor with 5-year survivals below 24 %. Multidisciplinary treatment is used to improve treatment efficacy of advanced stage of GC. However , it has been proven that gastric cancer is not particularly sensitive to current chemotherapy brokers, which is closely associated with intrinsic or obtained properties of gastric cancer cells. Therefore , discovery of early gastric cancer has become main pathway to improve the therapeutic efficacy. We have tried to establish an early gastric cancer pre-warning and diagnosis system since 2005 [4]. We hoped to find early gastric cancer cells in vivo by multi-mode targeting imaging and serum biomarker detection techniques. Our previous studies showed that subcutaneous and in situ gastric cancer tissues with 5 mm in diameter could be acknowledged and treated by using multifunctional nanoprobes such as breast cancer-associated antigen 1(BRCAA1)-conjugated fluorescent magnetic nanoparticles [5], human epidermal growth factor Zamicastat receptor-2 (HER-2) antibody-conjugated Rnase A (ribonuclease A)-associated CdTe quantum dots [6], folic acid-conjugated upper conversion nanoparticles [7], Arg-Gly-Asp (RGD) peptide-conjugated precious metal nanorods [8], ce6-conjugated carbon dots [9], ce6-conjugated Au nanoclusters (AuNCs) [10], HAI-178 antibody-conjugated fluorescent magnetic nanoparticles [11], CD44 monoclonal antibody-conjugated gold nanostars [12], and RNA nanoparticles carrying both ligand and siRNA [13]. However , clinical translation of these prepared nanoprobes still exist great challenge because their biosafety still needs a long term evaluation. We also screened out some Zamicastat breath biomarkers associated with gastric cancer [14], and established some methods and devices to detect these biomarkers [1517]. We also developed a giant magneto resistive (GMR) microfluidic system to detect the circulation gastric cancer cells [18]. However , up to date, serum biomarker detection to screen or find early gastric cancer is still most effective method. In the past decades, detection of serum tumor biomarkers has always been an important mean of diagnosis of various cancers. However , accepted unique serological biomarker for gastric cancer, like as Alpha-fetoprotein (AFP) intended for hepatocellular carcinoma (HCC) [19], remains absent. For this reason, combined detection of multiple serological biomarkers is an alternative effective method for predicting risk of gastric cancer. Several serological biomarkers based on a lot of literature can be used for early diagnosis of gastric cancer so far. Mutations in the tumor suppressor genep53are the most commonly observed in human cancers. In the serum of healthy subjects, the presence of P53 protein is extremely rare. Mutations in this gene cause an accumulation of nonfunctional proteins. The accumulated proteins are detectable in tissues, sloughed cells, blood, and other body fluids [20]. Thep53gene mutations are significantly correlated with Zamicastat P53 protein over-expression and contribute to genetic predisposition in gastric cancer patients [2123]. Carcinoembryonic antigen (CEA) is an acknowledged member of immunoglobulin superfamily, with a role as an intracellular adhesion molecule [24]. A high-serum CEA is associated Zamicastat with a number of malignancies, including colorectal, breast, gastric, and pancreatic cancers [25]. CA19-9 DP2 has a positive correlation with depth of invasion, nodal involvement, and peritoneal metastasis in gastric adenocarcinoma [26, 27]. In addition , many studies have shown that serum pepsinogen Zamicastat I (PG I) [28, 29], pepsinogen II (PG II) [30], PG I/PG II ratio [31, 32], andHelicobacter pylori(H. P. ) [3335] are also associated with an increased risk of gastric cancer. So , combined detection of above serum biomarkers is helpful to enhance precision of predicting gastric cancer risk. Enzyme-linked immunosorbent assay (ELISA) is widely used intended for clinical cancer diagnosis; nevertheless, these ordinary ELISA kits for single biomarker are not suitable for individual diagnosis, especially for patients with risk of gastric cancer. Moreover, the ELISA kits intended for batch samples from the different patients not only easily expose to cross-contamination, but also the operation is complicated. Self-assembled monolayers (SAMs) are widely used to immobilize biomolecules on precious metal surfaces [36]. The self-assembly process is the spontaneous organization.