Screening Of Protein Crystallization Conditions On A Concentration Gradient Droplet Array Chip

As the carrier of life, protein provides important information for life science research. Therefore, the study on protein has been growing with the advent of the post-genome era, and to obtain protein crystallization is becoming one of its focuses. However, using traditional methods, it is labor-intensive, sample-consuming and inefficient to manually set up a large number of screens. With the characteristics of low sample consumption, stable reaction conditions, rapid mixing, microfluidic droplets provide a strong technical platform for screening of protein crystallization conditions. This article aims to develop a microfluidic system which could generate an array of concentration gradient droplets, and the system is hopefully applicable to protein crystallization condition screening.In chapter1, the development of protein crystallization and droplet-based microfluidics was summarized. Protein crystal growth process and its influencing factors were introduced in detail. Conventional techniques and methods for protein crystallization, generation of microfluidic droplets and their application to protein crystallization were described briefly. The purpose and design of this paper were proposed in the end.In chapter2, on the basis of T-junction structure and channel network for forming concentration gradient which was developed by our group previously, a microfluidic chip which could generate an array of concentration gradient droplets was developed. The droplet array generation system features simple structure, stability and high throughput. The experiment results indicated that droplets could be generated simultaneously in96channels by adjusting the flow rates of the two phases. Droplets with good monodispersity were produced with the aqueous phase flow rate of1.0μL/min and the oil phase flow rate of35μL/min. RSD of the droplet size in the same channel was below5.0%, while in the96channels was7.0%.In chapter3, the concentration gradient droplet array chip was applied to screening of lysozyme crystallization conditions. The multiple factors or multiple precipitants of various concentrations for protein crystallization could be tested on a single chip. The effect of lysozyme concentration, precipitant concentration, pH value and different types of precipitants on lysozyme crystallization could be tested simultaneously. Compared with traditional screening methods, this system could significantly shorten the screening time, reduce consumption of reagents and improve the screening efficiency.In chapter4, the concentration gradient droplet array system and its application to screening of protein crystallization conditions were summarized and predicted.