ABSTRACT
In the areas of genomics and proteomics, there are increasing demands for the development of novel patterning techniques to create arrays of functional biomolecules or cells on the miniaturized devices, which could be used in various large-scale biomedical applications such as biosensing, proteomics, immunoassays or drug screening [1, 2]. Several processes have been demonstrated which are capable of patterning biomolecules with very high degree of spatial control including dip-pen lithography, inkjet printing, photolithography, nanoimprinting, etc. [3-10]. While the serial writing techniques provide individual addressability, the parallel printing processes offer an easy and fast protein patterning. However, very few of the above-mentioned techniques are capable of patterning cells. The cell microarrays, which provide the native environments for various biochemical reactions, are often used to investigate the expression of genes and the function of proteins [11]. In the past few years, many schemes have been proposed to fabricate cells microarrays
[12]. One of the most popular approaches is to print biomolecules on a chip where the desired types of cells are cultured. However, in such type of cell microarray, the cells are not confined. The separation of different colonies sometime becomes problematic. Another approach is to employ micro-contact printing where the extracellular matrix (ECM) molecules such as fibronectin, vitronecin and collagens are first patterned on the surfaces [13]. Then the growth of cells on the surfaces is guided through binding to these ECM molecules. However, in these two cases, only one type of cells can be used on a chip. Here we report the use of switchable superhydrophobic surfaces to create cell microarrays where two or more types of cells can simultaneously be cultured on different areas of the same chip.
