Direct Transfer of Preformed Patterned Bio-Nanocomposite Films on Polyelectrolyte Multilayer Templates Neeraj Kohli, Robert M. Worden, Ilsoon Lee * Introduction Functional, three-dimensional (3-D) nano and microstruc- tures composed of amphiphilic molecules, such as proteins, lipids, polyelectrolytes and dendrimers, have potential applications in drug screening devices, biosensors, bioca- talysis, optoelectronics, and other devices. [1–3] Conven- tionally, such 3-D structures can be created by using microcontact printing (mCP), [4] where an elastomeric polydimethylsiloxane (PDMS) stamp having the desired topographic pattern is coated with a molecular ink and then brought into contact with the surface. Removal of the stamp leaves behind a thin layer of ink having the same pattern as the stamp. Based on the chemical contrast between the inked features and the ink-free background, additional layers can then be selectively deposited on either the features or the background using thin film deposition methods such as layer-by-layer (LBL) assem- bly. [1] Full Paper Microarrays containing multiple, nanostructured layers of biological materials would enable high-throughput screening of drug candidates, investigation of protein-mediated cell adhe- sion, and fabrication of novel biosensors. In this paper, we have examined in detail an appro- ach that allows high-quality microarrays of layered, bionanocomposite films to be deposited on virtually any substrate. The approach uses LBL self-assembly to pre-establish a multi- layered structure on an elastomeric stamp, and then uses mCP to transfer the 3-D structure intact to the target surface. For examples, different 3-D patterns containing dendrimers, polyelectrolyte multilayers and two proteins, sADH and sDH, have been fabricated. For the first time, the approach was also extended to create over- laid bionanocomposite patterns and multiple proteins containing patterns. The approach overcomes a problem encountered when using mCP to establish a pattern on the target surface and then building sequential layers on the pattern via LBL self-assembly. Amphiphilic molecules such as proteins and dendrimers tend to adsorb both to the patterned features as well as the underlying substrate, resulting in low-quality patterns. By circumventing this problem, this research significantly extends the range of surfaces and layering constituents that can be used to fabricate 3-D, patterned, bionanocomposite structures. N. Kohli, R. M. Worden, I. Lee Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI-48824 Fax: þ1 517 432 1105; E-mail: leeil@egr.msu.edu Macromol. Biosci. 2007, 7, 789–797 ß 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/mabi.200700006 789