Nanoparticles in microdroplets: Recent advances in microfluidic generators for producing functional microbeads

Biomarkers reflect physiological states and disease progression in the human body. Their precise detection is crucial for accurate and effective diagnosis. Functional hybrid microbeads (FHMBs) with electrical, magnetic, and/or optical responsiveness have emerged as versatile platforms for signal amplification, transduction, and conversion. This review summarizes recent advances in microfluidic strategies for producing FHMBs, with emphasis on incorporating functional nanoparticles (NPs) into microdroplets. We discuss the advantages of microfluidics in generating monodisperse droplets, controlling composition, encapsulating functional NPs, and forming FHMBs through solidification processes. Key droplet‐generation strategies are summarized, encompassing passive and active mechanisms, as well as both on‐chip and off‐chip approaches, followed by an overview of solidification methods driven by physical or chemical processes. We classify FHMBs into four functional categories: electrical, optical, magnetic, and mixed response, based on their material composition, fabrication methods, and practical applications. Finally, we discuss the current challenges and suggest future research directions to advance the development of improved platforms for FHMBs production.