Capillary phenomenon-based pump-less biochip for uric acid determination

In this reported study, the authors developed a uric acid biochip that does not require extra driving force. Although liquid flow is performed in a very narrow gap (2 μm), the capillary force is generated in this microfluidic device, which was fabricated from poly(methyl methacrylate) (PMMA) using a micromachining technique. The authors have fabricated a 2 μm pillar array through hot-embossing and thermal bonding from a Si master mould. To increase the capillary force, the authors modified the PMMA surface by ultraviolet irradiation followed by poly-L-lysine coating. Electrodes were integrated into the microfluidic device to permit successful electrochemical measurement of uric acid with good reproducibility. This device also solves the problem of expenditure because of its potential scalability for mass production; although it is driven solely by capillary action, it does not require microfluidic pumps or any other additional power supply. The device is suitable for in situ analysis, diagnosis and house calls.