Double-sided 3D printing on paper towards mass production of three-dimensional paper-based microfluidic analytical devices (3D-μPADs)

Recently, much effort has been focused on developing three-dimensional, paper-based microfluidic analytical devices (3D-mu PADs) targeting in vitro diagnostics. However, 3D-mu PAD fabrication typically requires tedious assembly that hinders mass production. Here, we report on a fabrication method for 3D-mu PADs made of plastics without the need for additional assembly. Both sides of the paper were printed via liquid resin photopolymerization using a digital light processing (DLP) printer. The sample reservoir and detection zones are located on the top of the 3D-mu PADs, and three microchannels are located on the bottom. The detection limits for glucose, cholesterol, and triglyceride (TG) in phosphate-buffered saline (PBS) were 0.3 mM, 0.2 mM, and 0.3 mM, respectively. The detectable ranges of glucose, cholesterol, and TG in human serum were 5-11 mM, 2.6-6.7 mM, and 1-2.3 mM. These results suggest that our fabrication method is suitable to mass produce 3D-mu PADs with relative ease using simple fabrication processes.