26 Biofunctional interfaces for cell culture in microfluidic devices

This chapter presents various techniques that are employed to engineer and embed biofunctional interfaces in microfluidic platforms. Microfluidic systems exhibit high proficiency in rapid throughput and analysis, as well as small sample and reagent requirements. Achieving biofunctionalization, or controlled immobilization of specific biomolecules, within microchannels is of growing importance due to the rising capabilities of microfluidic systems in biomedical applications including three-dimensional cell culture platforms for tissue- and organ-on-a-chip technologies and point-of-care diagnostics. The formation of cell-functionalized microfluidic devices requires proper microfabrication techniques and biological patterning. Different coating and patterning processes can induce chemically reactive groups on the microchannel’s surface, which can then be used to establish a stable interaction between biomolecules of interest and the surface. The following sections explore widely used approaches to develop cell-laden microchannels: plasma- and silanization-based treatments, microcontact printing, microfluidic patterning, polymer grafting, and extracellular matrix-based hydrogel coating. Furthermore, this chapter introduces numerous surface blocking agents that prevent nonspecific adsorption of biomolecules and boost the sensitivity of biological assays. Through developing target-specific biofunctional interfaces, these techniques enhance the biological compatibility of microfluidic devices for a variety of microfluidic applications such as cell sorting, detection and isolation of circulating tumor cells, and organs-on-chips systems.