Microfluidic cloth-based analytical devices through simple correction pen direct-writing

In this paper, we report a simple and fast (<15 s) method to fabricate microfluidic cloth-based analytical devices (μCADs) through using a common and cheap correction pen. Specifically, commercially available correction pens were directly written on a piece of hydrophilic cloth. The written region with correction solution acted as hydrophobic barriers, and the non-written region constituted the hydrophilic channels. The formation mechanism of the hydrophobic barrier was investigated which indicated that the surface of the treated cloth was covered with numerous hydrophobic TiO2 particles. In addition, the resolution studies showed that the width of the smallest hydrophilic channel and hydrophobic barrier were ∼700 and ∼800 µm, respectively. Also, a series of 2D and 3D μCADs can be easily fabricated through this method. Finally, the μCADs were utilized for distance-based quantitative detection of glucose concentrations. Considering the cheapness and the simplicity of the fabrication method, we believe it has great potential to be used in limited regions or developing countries, and may open a new avenue to develop rapid detection devices in POCT cases.