Advances in nanoparticle synthesis assisted by microfluidics

The synthesis of nanoparticles (NPs) has garnered significant interest due to their wide-ranging applications across various emerging industries, including pharmaceuticals, electronics, food engineering, agriculture, wastewater management, and medicine. Research efforts have focused on controlling key NP characteristics, such as size, polydispersity, zeta potential, drug release, and encapsulation efficiency, to meet the demands of these applications. In this review, we explore how microfluidics offers a superior alternative to conventional physical, chemical, and biological synthesis methods. We discuss various microfluidic NP manufacturing strategies, broadly classified into passive and active methods. Active methods utilise external energy sources, such as thermal, electrical, electromagnetic, and acoustic inputs. In contrast, passive methods do not use external energy sources and instead rely on techniques like hydrodynamic flow focusing, vortex generation, droplet generation, and chaotic advection. We also highlight the challenges associated with NP synthesis in microfluidic devices. Finally, we examine the potential of integrating microfluidics with machine learning algorithms to develop "intelligent microfluidics" for NP synthesis.