Cell confinement in patterned nanoliter droplets in a microwell array by wiping

Cell patterning is useful for a variety of biological applications such as tissue engineering and drug discovery. In particular, the ability to localize cells within distinct fluids is beneficial for a variety of applications ranging from microencapsulation to high-throughput analysis. However, despite much progress, cell immobilization and maintenance within patterned microscale droplets remains a challenge. In particular, no method currently exists to rapidly seed cells into microwell arrays in a controllable and reliable manner. In this study, we present a simple wiping technique to localize cells within arrays of polymeric microwells. This robust method produces cell seeding densities that vary consistently with microwell geometry and cell concentration. Moreover, we develop a simple theoretical model to accurately predict cell seeding density and seeding efficiency in terms of the design parameters of the microwell array and the cell density. This short-term cell patterning approach is an enabling tool to develop new high-throughput screening technologies that utilize microwell arrays containing cells for screening applications. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res 93A: 547-557, 2010