New Platform And Strategy For Bioanalytical Based On Digital Microfluidics

With the rise of micrometer-scale total analysis systems(μTASs),microfluidics has been widely used in point-of-care testing,nucleic acid analysis,single cell research and other fields,with the merits of small reaction volume,high reaction efficiency,integration and miniaturization.The key of microfluidics is fluid control,which can be divided into passive manipulation and active manipulation.Passive manipulation realizes fluid manipulation by designing micro channels and pump/valve.Although this method is simple,the structure is complex and the processing is cumbersome.On the other hand,active manipulation is mainly based on light,electricity,magnetism or pressure,with the advantages of flexibility and fast response.Digital microfluidics is an active droplet control method based on microelectrode array,which can accurately manipulate large-scale discrete droplets.It has the advantages of automation,integration and small volume.The droplet system of digital microfluidics matches well with cell size,resulting in high reaction efficiency and low cost.Therefore,digital microfluidics is promising in single-cell analysis application.However,digital microfluidics platform requires high voltage power from external devices,which makes it expensive and not portable.Recently,triboelectric nanogenerator was proposed to convert mechanical energy into electricity,with the unique advantage of simple equipment and low cost.This self-powered device has been widely used in healthcare monitoring and wearable electronic devices,and is expected to replace the external high voltage power of digital microfluidics.In this thesis,we developed a digital microfluidics-based single-cell processing platform,which enabled rapid,efficient and nondestructive single-cell separation by constructing hydrophilic-hydrophobic interfaces.Based on this platform,we proposed a single-cell RNA sequencing method(Digital-RNA-seq)for sensitive,accurate and low-pollution single-cell gene expression measurement,which integrated single-cell RNA reverse transcription and cDNA amplification on the chip.In addition,we developed an automatic platform for single-cell RNA sequencing library preparing based on digital microfluidics(Digital-RNA-seq2).Digital-RNA-seq2 enabled integrated single-cell RNA reverse transcription,cDNA amplification,purification and sequencing library preparation,achieving integrated cell-in-library-out single-cell RNA sequencing,improved sensitivity and reduced cost of single-cell analysis.Furthermore,we developed a triboelectric nanogenerator-based self-powered digital microfluidics platform,without external high-voltage power device.This platform is low-cost,simple and portable for droplet manipulation by replacing the high voltage power device with daily triboelectrification.In addition,this platform realized discrete droplet manipulation in different volumes and different kinds,which would further promote the development of miniaturization,portability and integration digital microfluidics platform.