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In this work, we report for the first time a simple and robust method for constructing a 3D microfluidic analytical device on a single piece of hydrophobic cotton cloth. Specifically, laser scanning technology was applied to process hydrophilic regions at the top and bottom of a single piece of hydrophobic cloth. Symmetrical hydrophilic regions at the bottom and top constituted vertical microfluidic channels, and asymmetrical hydrophilic regions constituted transverse flow channels. Liquid flow velocity in 3D cloth-based microchannels can be adjusted flexibly by modifying laser parameters, and programmable laser scanning can be utilized to process 3D microfluidic devices with various patterns. Single-piece 3D cloth-based microfluidic devices formed via this method can be used in many fields such as information encryption and anti-counterfeiting, multi-liquid printing and liquid mixing dilution. Compared to traditional processing methods of 3D cloth-based microfluidic devices, the laser scanning method eliminates multiple complex and repetitive assembly processes, which is a significant advance in this research area. This processing method provides a new option for fast and large-scale manufacturing of 3D cloth-based microfluidic analysis devices for point-of-care testing application in undeveloped regions/countries. [ABSTRACT FROM AUTHOR]

Separation of plasma which is full of various biomarkers is critical for clinical diagnosis. However, the point-of-care plasma separation often relies on microfluidic filtration membranes which are usually limited in purity, yield, hemolysis, extraction speed, hematocrit level, and protein recovery. Here, we have developed a high-performance plasma membrane separation technique based on a Janus membrane and red blood cell (RBC) agglutination reaction. The RBC agglutination reaction can form larger RBC aggregates to separate plasma from blood cells. Then, the Janus membrane, serving as a multipore microfilter to block large RBC aggregates, allows the plasma to flow from the hydrophobic side to its hydrophilic side spontaneously. As a result, the separation technique can extract highly-purified plasma (99.99%) from whole blood with an ultra-high plasma yield (∼80%) in ∼80 s. Additionally, the separation technique is independent of the hematocrit level and can avoid hemolysis. [ABSTRACT FROM AUTHOR]