Development of Preparative Microfluidic Techniques for Lysis of Microbial Cells and Affinity Purification of Proteins

Abstract

In order to fully realise the benefits of microscale mammalian cell culture and microbial fermentation systems, a device capable of online sample preparation to enable further investigation of product quality is a key requirement. The aim of this work is to move toward such a device by designing and characterising a microfluidic lysis device and microaffinity chromatography device that are compatible with each other. The resulting microfluidic lysis device is useful for preparatory lysis of microbial cells. It works by mixing a lysis reagent (BugBuster MastermixTM), with microbial culture, using a T-Piece connection. Lysis takes place in a 700µm internal diameter fused silica capillary. The device was able to successfully lyse microbial cells with similar active Glutathione S Transferase release to sonication. The operating flowrate range of the device was 3.207µL min-1 to 6.414 µL min-1 and the device volume was 30µL - 60µL. The microaffinity chromatography column performed well in studies with pure Glutathione S Transferase. It showed good loading and elution behaviour. The breakthrough and elution curves, and quantity of protein eluted per unit bed volume, were similar to lab scale. The difference being as a result of experimental error. The column also performed well with a 100% clarified Escherichia coli lysate containing recombinant Glutathione S Transferase from Schistosoma japonicum. The eluate had a purity of 55% and concentration of 2.24 mg/ml. The column was fabricated from inexpensive fused silica capillary. It had an internal diameter of 700µm, a length of 5cm (the same length as a typical lab scale Glutathione Affinity column), and a bed volume of approximately 19µL. The operating flowrate range for the column was the same as the microlysis device

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