Highly sensitive, label-free and real-time detection of alpha-fetoprotein using a silicon nanowire biosensor

Abstract

Alpha-fetoprotein (AFP) is a tumor-associated fetal protein that can be expressed in large amounts in adult tumor cells, serving as a useful clinical tumor-marker. Silicon nanowire (SiNW) biosensors have emerged as a powerful tool in detecting protein biomarkers, due to their ultrahigh sensitivity, real-time response and label-free detection. We fabricated a SiNW-based field-effect transistor (FET) according to “top-down” methodology. First, anti-AFP antibodies were immobilized onto the surface of the SiNW-FET. A polydimethylsiloxane (PDMS) microchannel was then integrated to the modified SiNW-FET. Various concentrations of AFP were then pumped through the sensing area. We observed a current change that corresponded to binding of AFP onto the surface of our anti-AFP functionalized SiNW-FET biosensor. Concentrations of AFP as low as 0.1 ng/mL were detected. The results implicate our SiNW biosensor as an effective AFP biomarker detector with promising potential in clinical applications.

Key Words::

• Biosensors
• point-of-care testing
• proteins and enzymes
• nanotechnology
• microscopy

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

This work was supported by grants from the National Natural Science Foundation of China [No. 81371683/H1819], Medical Technology Major Projects of Wuxi Hospital Center [YGZX1105] and Clinical Medicine Project of Jiangsu Province [BL2014023].