Construction and application of multicomponent fluorescent droplets

The rapid development of microfluidic technology has led to the evolution of microdroplets from simple emulsion structures to complex multilayered and multicompartmental configurations. These advancements have endowed microdroplets with the capability to contain multiple compartments that remain isolated from one another, enabling them to carry different molecules of interest. Consequently, researchers can now investigate intricate spatially confined chemical reactions and signal transduction pathways within subcellular organelles. Moreover, modern microdroplets often possess excellent optical transparency, allowing fluorescently labelled, multi-layered, and compartmental droplets to provide detailed insights through real-time, in situ, and dynamic fluorescence imaging. Hence, this review systematically summarizes current methodologies for preparing multicomponent microdroplets and their applications, particularly focusing on fluorescent microdroplets. Additionally, it discusses existing critical challenges and outlines future research directions. By offering a comprehensive overview of the preparation methods and applications of fluorescent microdroplets, this review aims to stimulate the interest of researchers and foster their utilization in more complex and biomimetic environments.