A review on the development and application of microfluidic concentration gradient generators

This paper reviews the development and application of concentration gradient generators based on microfluidics. Generating solutions of varying concentrations is a frequent requirement in numerous experiments and applications. Traditional approaches involve the preparation of solutions with varying concentrations or the dilution of highly concentrated solutions. Nevertheless, these methods are intricate, time-consuming, and susceptible to errors. The advent of microfluidic concentration generators presents a novel concept for the realms of chemistry, biology, and medicine, allows biological or chemical experiments to be performed on a device with a measurement size of a few square centimeters or even smaller, thus greatly reducing the number of basic routine biological or chemical laboratory operations, such as sample preparation, reaction, separation, and analysis. In this review, we discuss the development and application of microfluidic concentration gradient generators through observation, introduce the development history of microfluidic concentration gradient generators and how they are used, summarize their wide range of applications in various fields, and discuss the possible future development direction of microfluidic concentration gradient generators.