Microfluidic Paper Analytical Devices With Hybrid Flow Channels

Paper-based microfluidics made its debut in 2007 from Whitesides' group.Microfluidic paper analytical devices(p.PADs)has witnessed booming development over the past decade because of their unique advantages compared with traditional microfluidic analytical devices.Paper-based substance,because of low cost,easy to manufacture,and easy to use,makes it an ideal candidate for commercialization in healthcare,environmental monitoring and food safety.Although this kind of p,PADs brings us many conveniences,it also has some structural defects.With their special porous structures,Liquid reagents can thus be transported by capillary action inside the paper without the need of additional driving force.However,this kind of transportation has poor directionality,and usually generates large resistance to liquid flow and lead to nonspecific surface absorption of samples,making it difficult to transport macromolecules.All of these have limited the application of the ?PADs,especially for the transport and analysis of macromolecules.In this investigation,we will begin by building flow channels on the surface of paper-based substance.By transporting the liquid on the surface of the paper,we can reduce non-specific adsorption and accelerate the flow.In chapter 2,we introduce the paper capillary empowered ?PAD(PCap-?PAD)to transport different types of reagents.We made a capillary channel consisting of paper and tape by carving a groove in paper and sticking it with tape.Like traditional microfluidic chip,this kind of paper capillary in this chip can quickly and controllably transport reagents to the detection area/.The resulting device thus well supports easy use,high throughput and repeatable assays,and it can also be applied to the analysis of different sizes of samples.In subsequent experiments,we successfully performed metal ion,protein and microbe analysis using this chip.In chapter 3,we fabricate microfluidic PDMS on paper(POP)devices.We firstly reveal the correspondence between the curing time of PDMS and the temperature at high temperatures.Secondly,by controlling a series of conditions,we obtain a PDMS-patterned paper chip with higher resolution successfuly.The patterned area of the chip and the PDMS channel can generate reversible bond.The liquid reagent flows in a smooth channel and penetrates into the paper area,avoiding the adsorption of the channel itself.Follow-up experiments introduce three typical liver function markers:serum protein,alkaline phosphatase(ALP)and aspartate aminotransferase(AST).Successful analysis of markers of liver function proves its superiority for macromolecular transport and detection.