High Density Addressable Protein and Cell Patterning via Switchable Superhydrophobic Microarrays

Abstract

There have been increasing research interests in the development of novel nano or micro-patterning techniques to create arrays of functional biomolecules for miniaturized assays, which could be used in various biomedical applications such as biosensors, proteomic, immunoassays or drug screening. Several techniques have been demonstrated capable of writing or printing biomolecules with very high degree of spatial control including dip-pen lithography, nanopipet, inkjet printing, photolithography, micro contact printing etc. The serial writing techniques provide the individual addressability whereas the parallel printing processes offer easy and fast protein patterning. However, it remains difficult to create complex patterns, such as functional multicomponent protein arrays, in parallel with individual addressability. Here we describe a novel approach to fabricate functional multicomponent protein and cell arrays where the electrowetting effect was employed to convert a water-repellent superhydrophobic surface into a wettable one allowing fast and high density addressable protein and cell deposition on the otherwise protein- and cell-resistant superhydrophobic surface. It has been shown that each element on the switchable superhydrophobic microarray could be addressed individually and different types of functional biomolecules could be selectively deposited on the microarray. Such protein patterning technique offers several advantages over other techniques including parallel protein deposition with individual addressability, possibility for large-scale patterning and easy integration with microfluidic system. The facts that the superhydrophobic surfaces can be fabricated from many hydrophobic materials and the electrowetting works for most dielectric materials allow great flexibility in the selection of the surface materials for protein deposition.