A paper-based device with an adjustable time controller for the rapid determination of tumor biomarkers.

Paper-based microfluidic chips have shown great potential for use in rapid clinical diagnostics. In this work, we present a paper-based device that integrates an electromagnetically actuated valve and an adjustable time controller for the simultaneous detection of multiple tumor biomarkers. The time controller consists of a timing channel and two movable conductive iron bands that function as an electric switch. Once the conductive iron bands are connected by the fluid flow, the circuit would be closed to actuate the magnetic valve, initiating chemiluminiscent immunoassay (CLIA) reactions. Using a HRP- O -phenylenediamine-H 2 O 2 detection system, simultaneous detection of different concentrations of carcinoembryonic antigens (CEA) was demonstrated. The resulting CLIA peak intensity exhibited a good linear relationship with the logarithm of the CEA concentration from 0.1–80 ng mL −1 . Further experiments showed that the developed device was capable of detecting multiple tumor biomarkers simultaneously. We can program different incubation times for the detection of different biomarkers by moving the conductive bands on this paper-based device. In this study, only 16 min was required to complete CEA detection. This strategy greatly shortens detection time compared to the conventional chemiluminiscence technique for CEA detection (nearly 2 h). This paper-based device provides a simple and inexpensive platform for immunoassay-based detection of disease-related biomarkers. [ABSTRACT FROM AUTHOR]