Detection and Analysis of Droplets in Microfluidic Devices: A Review

Droplet microfluidics marks a significant advancement from the traditional continuous flow systems by utilizing two non-mixing liquid phases to generate droplets for further applications. This innovative technology encases samples within droplets, creating isolated compartments that enhance analytical sensitivity. It achieves this enhancement by concentrating substances of low abundance and accelerating the attainment of reaction equilibrium and detection thresholds. Notably, the technology allows for the adjustment of droplet size to approximate that of cells, marrying the benefits of minimal reagent use with the efficiency of high-throughput microfluidic experimentation. Beyond controlling droplet flow in microscopic channels, it consistently produces droplets of uniform size, ensuring reproducibility. Such precision finds widespread use across the food, cosmetics, and pharmaceutical sectors, laying the groundwork for novel biological and medical research avenues. This review presents an in-depth examination of recent advancements in droplet microfluidics technology. It specifically addresses the strategic methodologies for droplet analysis, offering a comprehensive summary of prevalent techniques for droplet signal amplification, alongside both optical and non-optical detection methods. Furthermore, it critically evaluates the existing limitations within droplet microfluidics technology and anticipates prospective directions for its future evolution.