Analytical Sciences

Multiplex MicroRNA Detection on a Surface-Functionalized Power-Free Microfluidic Chip

Ryo ISHIHARA,*1 Ryoichi KITANE,*2 Yoshitsugu AKIYAMA,*3 Shoko INOMATA,*2 Kazuo HOSOKAWA,*4 Mizuo MAEDA,*4 and Akihiko KIKUCHI*2

*1 Faculty of Medicine, Juntendo University, 1-1 Hirakagakuendai, Inzai, Chiba 270-1695, Japan
*2 Department of Materials Science & Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan
*3 Faculty of Industry Science & Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan
*4 Bioengineering Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

Circulating microRNAs (miRNAs) have emerged as promising cancer biomarkers because their concentration profiles in body fluids are associated with the type and clinical stage of cancer. For multiplex miRNA detection, a novel surface-functionalized power-free microfluidic chip (SF-PF microchip) has been developed. The inner surface of the SF-PF microchip microchannels was functionalized via electron beam-induced graft polymerization and immobilization of capture probe DNAs. Simultaneous and specific duplex miRNA detection was achieved on the line-type SF-PF microchip with detection limits of 19.1 and 47.6 nmol L⁻¹ for hsa-miR-16 and hsa-miR-500a-3p, respectively. Moreover, simultaneous and specific triplex miRNA detection was achieved on the stripe-type SF-PF microchip. The sample volume required for this microchip was 0.5 μL, and the time required for detection was 17 min. These results indicate that up to six types of miRNAs could be detected without compromising the advantages of the previous SF-PF microchips for cancer point-of-care testing.

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