Capillary-Composited Microfluidic Device For Dropelt Formation And Transformation Of Escherichia Coli

Escherichia coli (E. coli) transformation is defined as the introduction of foreign DNA into E. coli which will chang the characteristics of E. coli, and can be steadily passed on. E. coli transformation is a conventional molecular biology experiment in the field of life science, which is to study gene function, protein and other functional traits, and is also the main research method and mean of production in genetic engineering, protein engineering, cell engineering, fermentation engineering and so on. Microfluidic chip technology is a new research tool emerging from the field of analytical chemistry, which has been extended to the fields of life sciences, medical diagnostics, environmental science, military and criminal science and so on, and has been widely studied and applied. Microfluidic chip technology has characteristics of less sample consumption (nL, pL), short reaction time, automation, miniaturization and integration. Its development goal is to achieve "lab on a chip", which is to replace the traditional method of a series of experiments operation, such as sample preparation, injection, reaction, separation and detection on a small chip. Researchers have made many efforts to achieve the objective and E. coli transformation is one of them.This paper describes the construction of capillary-composited microfluidic device for droplet formation and transformation of E. coli and the shows the results obtained. The main results are as follows:(1) The construction of capillary-composited microfluidic device for droplet formationTwo phase sample introduction channels were designed in the microfluidic chip, and a hydrophobic modified silica capillary was inserted into intersection. Driving by the constant flow pumps, the droplets were formed in the junction of microfluidic chip and the capillary and directly flowed into the capillary. Uniform, controlable size and formation frequency, and stable streamlined water droplets can be generated using the system. Droplet size and frequency can be used to predict by the theoretical formula.(2) The construction of capillary-composited microfluidic device of single-phase and its application in transformation of E. coliAppling the advantages of the small diameter, fast and uniform heat transfer of the capillary, and advantage of the rapid mixing in the microfluidic chip, capillary-composited microfluidic device of single-phase was constructed, and the chemical heat shock transformation of E. coli was performed on the device. E. coli transformation was successful achieved on platform and similar transformation efficiency, higher transformation frequency, less amount needed and less time consumed were obtained with the traditional method. What is more, in the new system, sample introduction, sample mixing, heat shock and collection of transformation mixture were carried out online and automatically.(3) The construction of capillary-composited microfluidic device of two-phase and its application in transformation of E. coliBased on the successful construction of capillary-composited microfluidic device for droplet formation and construction of capillary-composited microfluidic device of single-phase for transformation of E. coli, we constructed the capillary-composited microfluidic device of two-phase for transformation of E. coli. The results show similar laws with the single-phase system, similar transformation efficiency and higher transformation frequency.