A hybrid microfluidic-vacuum device for direct interfacing with conventional cell culture methods

We have developed and validated a novel microfluidic device that can directly interface with conventional tissue culture methods to generate and maintain controlled soluble environments in a Petri dish. It incorporates separate sets of fluidic channels and vacuum networks on a single device that allows reversible application of microfluidic gradients onto wet cell culture surfaces. Stable, precise concentration gradients of soluble factors were generated using simple microfluidic channels that were attached to a perfusion system. We successfully demonstrated real-time optical live/dead cell imaging of neural stem cells exposed to a hydrogen peroxide gradient and chemotaxis of metastatic breast cancer cells in a growth factor gradient.This paper describes the design and application of a versatile microfluidic device that can directly interface with conventional cell culture methods. This platform provides a simple yet versatile tool for incorporating the advantages of a microfluidic approach to biological assays without changing established tissue culture protocols.Gradients of chemokines and growth factors play an important role in many developmental and physiological processes such as axon guidance [1], immune response [2], morphogenesis [3], and cancer metastasis [4,5]. Traditionally, Boyden chamber [6], under-agarose assay [7], and micropipette-based assay [8] have been used to study cellular behavior in soluble gradients. Unfortunately, these conventional assays are not capable of generating and maintaining stable gradients over long periods due to inherent limitations of their macroscale approach [6,7]. In addition, they typically require relatively large amounts of costly reagents and often do not allow real-time monitoring of cell behavior.Recent developments in microfluidic devices that apply miniaturization technologies from the microelectronics industry have resulted in microscale devices that hold the promise of overcoming limitations imposed by conventio