title: Understanding wax screen-printing: a novel patterning process for microfluidic cloth-based analytical devices.
abstract: In this work, we first introduce the fabrication of microfluidic cloth-based analytical devices (μCADs) using a wax screen-printing approach that is suitable for simple, inexpensive, rapid, low-energy-consumption and high-throughput preparation of cloth-based analytical devices. We have carried out a detailed study on the wax screen-printing of μCADs and have obtained some interesting results. Firstly, an analytical model is established for the spreading of molten wax in cloth. Secondly, a new wax screen-printing process has been proposed for fabricating μCADs, where the melting of wax into the cloth is much faster (∼5 s) and the heating temperature is much lower (75 °C). Thirdly, the experimental results show that the patterning effects of the proposed wax screen-printing method depend to a certain extent on types of screens, wax melting temperatures and melting time. Under optimized conditions, the minimum printing width of hydrophobic wax barrier and hydrophilic channel is 100 μm and 1.9 mm, respectively. Importantly, the developed analytical model is also well validated by these experiments. Fourthly, the μCADs fabricated by the presented wax screen-printing method are used to perform a proof-of-concept assay of glucose or protein in artificial urine with rapid high-throughput detection taking place on a 48-chamber cloth-based device and being performed by a visual readout. Overall, the developed cloth-based wax screen-printing and arrayed μCADs should provide a new research direction in the development of advanced sensor arrays for detection of a series of analytes relevant to many diverse applications.
authors.affiliation: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China. Electronic address: liuminxthb@163.com.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.affiliation: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China. Electronic address: zhangcs@scnu.edu.cn.
authors.forename: Chunsun
authors.initials: C
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China. Electronic address: 937045102@qq.com.
authors.forename: Feifei
authors.initials: F
authors.lastname: Liu
mesh_terms: D000818:Animals; D002417:Cattle; D003124:Colorimetry / Q000295:instrumentation; D032561:Cotton Fiber; D004867:Equipment Design; D005947:Glucose / Q000032:analysis*; D006358:Hot Temperature; D057927:Hydrophobic and Hydrophilic Interactions; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D011327:Printing / Q000379:methods*; D012710:Serum Albumin, Bovine / Q000032:analysis*; D013784:Textiles / Q000032:analysis; D014885:Waxes / Q000737:chemistry*
chemical_list: D014885:Waxes; D012710:Serum Albumin, Bovine; D005947:Glucose
keywords: Colorimetric detection; High-throughput; Low-cost fabrication; Microfluidic cloth-based analytical devices; Small-batch manufacturing; Wax screen-printing