Cell micropatterning on an albumin-based substrate using an inkjet printing technique.

Positioning of cells in a desired pattern on a substrate is an important technique for cell-based technologies, including the fundamental investigation of cell functions, tissue-engineering applications, and the fabrication of cell-based biosensors and cell arrays. Recently, the inkjet printing technique was recognized as a promising approach to the creation of cellular patterns on substrates, and it has been achieved by the printing of living cells or cell adhesive proteins. In this article, we created complex cellular patterns by using an albumin-based substrate and inkjet printing technique. Albumin was cross-linked using ethylene glycol diglycidyl ether. Subsequent casting of the cross-linked albumin solution onto glass plates prevented cells from adhering to their surfaces. Through screening various chemical reagents, we found that these cross-linked albumin surfaces dramatically changed into cell adhesive surfaces after immersion in cationic polymer solutions. Based on this finding, cell adhesive regions were prepared with a desired pattern by printing the polyethyleneimine (PEI) solution onto a cross-linked albumin substrate using a modified commercial inkjet printer. Various cellular patterns including figures, letters, and gradients could be fabricated by seeding mouse L929 fibroblast cells or mouse Neuro-2a neuroblastoma cells onto the printed PEI-patterned substrate. Compared with the printing of fragile living cells or proteins, printing of stable PEI circumvents clogging of printer head nozzles and enables reproducible printing. Therefore, the present method will allow the creation of complex cell patterns.