A reagentless electrochemical immunosensor based on probe immobilization and the layer-by-layer assembly technique for sensitive detection of tumor markers

作者：Cong Qiumei; Bian Hongmei^*; Yu Zhaoxia; Liu Jiyang; Xi Fengna

来源：Analytical Methods, 2015, 7(22): 9655-9662.

DOI：10.1039/c5ay01871d

Facile electrochemical methods for highly sensitive detection of tumor markers provide great advances in early clinical diagnosis of cancer and public health protection. Herein, a reagentless electrochemical immunosensing platform was developed for sensitive immunoassay of tumor biomarkers based on surface-confined probes and the layer-by-layer assembly technique. Ferrocene grafted cationic polymer polyethyleneimine (PEI-Fc) was modified on chemically reduced graphene oxide (rGO) to form a redoxactive and positively charged PEI-Fc-G nanocomposite. Through the layer-by-layer electrostatic assembly technique, the positively charged PEI-Fc-G and negatively charged anionic polyelectrolyte sodium-p-styrene (PSS) were alternately assembled on a negatively charged Au electrode. Based on the biospecific binding of lectin and sugarprotein, the concanavalin A (Con A) lectin monolayer served as the linker to immobilize sugarprotein (horseradish peroxidase, HRP) labeled anti-CEA antibody (HRP-Ab) on the surface of the (PEI-Fc-G/PSS)(n)/PEI multilayer substrate. With carcinoembryonic antigen (CEA) being the model tumor biomarker, the as-prepared immunosensor presented high selectivity and good stability for sensitive and reagentless detection of CEA with a wide range of 0.1 ng mL(-1) to 120 ng mL(-1) (R-2 = 0.9963) and a detection limit as low as 60 pg mL(-1) at a signal/noise ratio of 3. The proposed immunosensor might serve as a versatile platform for reliable cancer diagnostics clinical and biochemical analysis.

• 出版日期2015
• 单位浙江理工大学