A stand-alone pressure-driven 3D microfluidic chemical sensing analytic device

This study introduces a new stand-alone pressure-driven 3D microfluidic chemical sensing analytic device (PD-PAD), fabricated by enclosing a cover substrate and inserting a void-channeled substrate on a conventional capillary-driven microfluidic paper-based analytical device (CD-PAD). Adhesive cold laminating film and filter paper were used as a substrate. The flow rates of 3D PD- and CD-PAD platforms were compared through five different character-shaped microfluidic channels. A single 60-mu L drop of fluid inducing 0.4 mbar of pressure showed that the PD-PAD was roughly 300-fold faster than the CD PAD. The more input pressure in the PD-PAD increased, the more flow increased. The structures with the curved channels less than 90 degrees led to a decreased flow rate in the CD-PAD, but did not affect the PD PAD. The superior flow rate in the PD-PAD was likely due to the concurrence of the pressure-driven and capillary-driven flows. The glucose and albumin concentrations with a clinically relevant range and pH levels were successfully detected. Therefore, a stand-alone 3D microfluidic PD-PAD platform has great potential for assessing for the presence of diseases in very urgent situations such as the operating room or for use in low-cost and fast point-of-care applications. (C) 2016 Elsevier B.V. All rights reserved.