Droplets-Based Microfluidics as a Platform to Design Food-Grade Delivery Systems Based on the Entrapped Compound Type

Microfluidic technology has become a powerful tool for several applications in chemistry, physics, biology, and engineering. Benefiting from the advantages of flowing fluids in the laminar regime, droplet-based microfluidics enable the development of various delivery systems based on food-grade emulsions, such as multiple emulsions, microgels, microcapsules, solid lipid micro-particles, and giant liposomes. Besides, by manipulating fluids on a micrometer scale with low-energy demand, it is possible to control the size, shape, and dispersity of droplets generated, which makes microfluidic emulsification an excellent strategy to modulate delivery system properties depending on the entrapped compound type. Thus, this review points out the most current advances in droplet-based microfluidic processes, in which food-grade materials were successfully utilized to develop simple and complex delivery systems. In that context, we sum-marized the principles of droplet-based microfluidics, introducing the most common microde-vices geometries, manufacturing materials, and forces involved in the different droplet generation processes within the microchannels. Subsequently, the encapsulated compound type, classified as lipophilic or hydrophilic functional compounds, was used as a starting point to present current advances in delivery systems based on food-grade emulsions and assembly using microfluidic technologies. Finally, we discuss the limitations and perspectives of scale-up in droplet-based microfluidic approaches, including the challenges that have limited the transition of microfluidic processes from lab-scale to industrial-scale.