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Cell Growth on Zein Surfaces Self-Assembled on Patterned Templates

Qin Wang1, Shifeng Li2, Chang Liu2, and Graciela W. Padua1. (1) Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, 382/D AESB, 1304 W. Pennsylvania Ave., Urbana, IL 61801, (2) Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 203A Engineering Hall, 1308 W. Green Street, Urbana, IL 61801

Zein nano and micro scale structures were built on 16-mercaptohexadecanoic acid (MHA) templates patterned on gold surfaces by dip-pen nanolithography (DPN) and micro-contact printing (µCP). Zein shows differential adsorption between MHA and 1-octadecanethiol (ODT), used as a background ink. Zein molecules formed high raise structures on MHA surfaces and low laying deposits on ODT. Topographical features of zein deposits, as observed by atomic force microscopy (AFM) were clearly defined owed to zein self-assembly properties and precision nanolithography. Zein structures may find use in construction of cell growth scaffolding.

Zein molecules adsorbed on surfaces with different hydrophobicity was investigated for its feasibility of cell attachment and proliferation in order to obtain information that could be applied for spatially organizing cells. Uniform hydrophilic and hydrophobic surfaces were prepared by self-assembly MHA and ODT on gold-coated glass slides. Micro patterned surfaces were generated by micro-contact printing (µCP) of MHA on gold-coated substrates and backfilling with ODT solution. Zein uniform surfaces and zein patterns were prepared by submerging the uniform and patterned substrates in zein solution and let it self-assembly on monolayers of carboxyl and methyl groups, respectively. Thus made substrates were used to culture mouse fibroblast cells (NIH 3T3), while cell culture dish was chosen as control. It was found that both the density and aspect ratio of cells were significantly higher when cell grew on zein deposited on carboxyl surfaces than it deposited on methyl surfaces. Results indicated that zein generated a polar surfaces when interact with carboxyl groups which favorite cells to attach and proliferate, while on methyl groups zein surfaces were hydrophobic. Cells seeded on patterned zein surfaces attached and proliferated exclusively on zein-MHA lines. This preliminary study demonstrates that zein is a useful growth substrate for hosting cells and further more to control spatial orientations of cells upon adsorbing on to surfaces with opposite hydrophobicity.