Microfluidic cell culture has been a research area with great attention the last decade due to its potential to mimic the in vivo cellular environment more closely compared to what is possible by conventional cell culture methods. Many exciting and complex devices have been presented providing possibilities for, for example, precise control of the chemical environment, 3D cultures, controlled co-culture of different cell types or automated, individual control of up to 96 cell culture chambers in one integrated system. Despite the great new opportunities to perform novel experimental designs, these devices still lack general implementation into biological research laboratories. In this project, the usability and applicability of microfluidic cell culture systems have been investigated. The tested systems display good properties regarding optics and compatibility with standard laboratory equipment and procedures. Such highly usable systems were achieved by integration of fluidic actuation, liquid reservoirs, liquid interconnections and cell culture chambers in a single portable unit. However, improvements regarding robustness of individual system parts and thereby reliability of the systems are shown to be needed. This is possibly one of the reasons for the lack of implementation of microfluidic cell culture systems into biological research laboratories. Procedures to perform long-term microfluidic perfusion cell culture experiments have been established. Furthermore, successful application of the microfluidic perfusion cell culture system is shown by investigation of adipose-derived stem cell (ASC) differentiation into adipocytes, where we have revealed that paracrine/autocrine signaling is involved in differentiation of a population of ASCs into adipocytes. We have thereby demonstrated that microfluidic perfusion cell culture systems are a more powerful and a useful tool to investigate paracrine/autocrine signaling within a cell population compared to conventional static cell culture. Thus, we have been able to perform novel biological research by the use of our developed microfluidic perfusion cell culture systems.