Stem cell culture and differentiation in microfluidic devices toward organ-on-a-chip

Microfluidic lab-on-a-chip provides a new platform with unique advantages to mimic complex physiological microenvironments in vivo and has been increasingly exploited to stem cell research. In this review, we highlight recent advances of microfluidic devices for stem-cell culture and differentiation toward the development of organ-on-a-chip, especially with an emphasis on vital innovations within the last 2 years. Various aspects for improving on-chip stem cell culture and differentiation, particularly toward organ-on-a-chip, are discussed, along with microenvironment control, surface modification, extracellular scaffolds, high throughput and stimuli. The combination of microfluidic technologies and stem cells hold great potential toward versatile systems of 'organ-on-a-chip' as desired. Stem cells, capable of self-renewing and differentiating into cells of various tissue types, are drawing more and more attention for their enormous potential in many clinically associated applications that include drug screening, disease modeling and regenerative medicine. Conventional cell culture methods, however, have proven to be difficult to mimic in vivo like microenvironments and to provide a number of well-controlled stimuli that are critical for stem cell culture and differentiation. In contrast, microfluidic devices offer new capacities and unique advantages to mimic complex physiological microenvironments in vivo, and has been increasingly applied to stem cell research.