Fabrication and detection of microvalves for SPR array sensing

This paper presents a microfluidic system with integrated microvalves used for SPR sensing. The microfluidic system consists of multi-layers polydimethylsiloxane (PDMS)-polymethylmethacrylate (PMMA) structure and the characteristics of these microvalves are tested by using conductance method in which electrodes are embedded at the inlets and outlets of microfluidic channels to form circuit loops. The detection results indicate that microvalve can be closed completely when control pressure reaches 2.7 bar and closing status is relative with pressure supply time. Simultaneous actions of multiple microvalves are also tested to ensure that samples and reagents can be controlled to flow through flow cell in predefined order. In SPR detection experiments, the microfluidic system is mounted on a SPR array sensing system and the injection of NaCl solutions are controlled by microvalves, and curves of phase change in different areas of the sensing chip are obtained. The results show that these microvalves are reliable and practical for SPR array sensing. (C) 2011 Elsevier B.V. All rights reserved.