Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Physical Sciences, Technology, Biochemical Research Methods, Chemistry, Multidisciplinary, Chemistry, Analytical, Nanoscience & Nanotechnology, Instruments & Instrumentation, Biochemistry & Molecular Biology, Chemistry, Science & Technology - Other Topics, CULTURE, DEVICE, ASSAYS, Cell Adhesion, Cell Line, Cell Survival, Cells, Electrowetting, HeLa Cells, Humans, Hydrophobic and Hydrophilic Interactions, Microfluidic Analytical Techniques, Miniaturization, Particle Size, Polytetrafluoroethylene, Surface Properties, Hela Cells, 03 Chemical Sciences, 09 Engineering, Analytical Chemistry, 34 Chemical sciences, 40 Engineering

Abstract:

In this paper we report on the controlled biofunctionalization of the hydrophobic layer of electrowetting-on-dielectric (EWOD) based microfluidic chips with the aim to execute (adherent) cellbased assays. The biofunctionalization technique involves a dry lift-off method with an easy to remove Parylene-C mask and allows the creation of spatially controlled micropatches of biomolecules in the Teflon-AF layer of the chip. Compared to conventional methods, this method (i) is fully biocompatible; and (ii) leaves the hydrophobicity of the chip surface unaffected by the fabrication process, which is a crucial feature for digital microfluidic chips. In addition, full control of the geometry and the dimensions of the micropatches is achieved, allowing cells to be arrayed as cell clusters or as single cells on the digital microfluidic chip surface. The dry Parylene-C lift-off technique proves to have great potential for precise biofunctionalization of digital microfluidic chips, and can enhance their use for heterogeneous bio-assays that are of interest in various biomedical applications.