A Review of Microfluidic Chip-Based Strategies for Extracellular Vesicle Isolation: Bridging Traditional Methods and Clinical Translation

Abstract

Extracellular vesicles (EVs), including exosomes, have emerged as powerful biomarkers and therapeutic vectors due to their molecular content and accessibility in biofluids. However, reliable EV isolation remains a significant challenge, particularly in clinical settings where high purity, low volume, and rapid processing are essential. This review systematically examines current EV isolation techniques, focusing on both conventional approaches such as ultracentrifugation, immunoaffinity capture, and size-exclusion chromatography and the rapidly evolving landscape of microfluidic technologies. Special attention is given to the two primary categories of microfluidic isolation: affinity-based and label-free systems. Affinity-based microfluidics utilize surface markers and ligand interactions to selectively isolate EV subpopulations with high specificity but face trade-offs in throughput and marker dependence. In contrast, label-free microfluidic platforms exploit physical properties like size, electrical charge, and acoustic responsiveness to enable gentle, high-throughput separation without biochemical labeling, preserving vesicle integrity and avoiding selection bias. Through a comparative evaluation of isolation performance, sample requirements, and scalability, this review highlights how microfluidic technologies address the core limitations of traditional methods. Furthermore, it discusses hybrid systems that integrate affinity and label-free mechanisms for enhanced efficiency and flexibility. We conclude by exploring future directions in automation, parallelization, and point-of-care integration, emphasizing the role of microfluidic EV isolation in advancing precision diagnostics and translational research. Together, these insights underscore the need for continued innovation toward standardized, clinically adaptable EV isolation platforms.