Microfluidic assembly of food-grade delivery systems: Toward functional delivery structure design

Background: Microfluidic process is an emerging technique that can be applied to fabricate functional delivery systems with a precise control. Assembling food-grade delivery systems using microfluidic platforms is gaining more and more interest. Synthetic polymers have been extensively studied for microfluidic assembly as wall materials, while very few of them are food-grade materials. In the past decade, several food-grade biopolymers were found as feasible materials for microfluidic assembly. This review will summarize the recent advances in microfluidic process in which food-grade materials were successfully utilized to fabricate various delivery systems. Scope and approach: In this review, the significance of controlled delivery in food-related applications is addressed. Using a microfluidic device, controlled delivery can be achieved by the accurate structural design and the precise production of the delivery systems. An introduction of microfluidic devices is presented, including mechanisms, basic principles in physics, and chip designs. Previous studies that used food-grade materials to fabricate delivery systems in microfluidic devices are summarized, categorized and discussed. Current hurdles and future directions are implied. Key findings and conclusions: The principles of microfluidic systems and categorized five common delivery matrices with food-grade or nonfood-grade materials are discussed. Various food-grade materials showing great potential in microfluidic process, such as lipids and carbohydrates, are introduced. Scalability and reliability have always been issues toward the mass production using microfluidics and a few solutions are discussed. Additional studies focusing on prevention of clogging during a microfluidic production are needed, especially when biomaterials are used.