pubs.acs.org/Langmuir Chemical and Biological Characterization of Thiol SAMs for Neuronal Cell Attachment K. Jans,* ,†,‡,# B. Van Meerbergen, †,§, ) ,# G. Reekmans, † K. Bonroy, † W. Annaert, ) G. Maes, ‡ Y. Engelborghs, § G. Borghs, †,^ and C. Bartic †,^ † Bioelectronic Systems Group, IMEC vzw, Kapeldreef 75, 3001 Leuven, Belgium, ‡ Departement of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium, § Department of Biochemistry, Molecular and Structural Biology Section, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium, ) Laboratory for Membrane Trafficking, Center for Human Genetics, KU Leuven, O&N1, Herestraat 49-bus 602, 3000 Leuven, and Department of Molecular and Developmental Genetics VIB, Belgium and ^ Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium. # Both authors contributed equally. Received July 11, 2008. Revised Manuscript Received January 29, 2009 Cellular adhesion and growth on solid-state surfaces is the central theme in the development of cell- based biosensors and implantable medical devices. Suitable interface techniques must be applied to construct stable and well-organized thin films of biologically active molecules that would control the development of neuronalcells on chips. Peptides such as RGD fragments, poly- L -lysine (PLL),or basallamina proteins, such as laminin or fibronectin,are often used in order to promote cellular adhesion on surfaces. In this paper we describe the characterization of several self-assembled monolayers (SAMs) for their ability to anchor a laminin-derived synthetic peptide, PA22-2, a peptide known to promote neuronal attach- ment and stimulate neurite outgrowth. We have evaluated the immobilization of PA22-2 onto 16-mercaptohex- adecanoicacid, 4-maleimide-N-(11-undecyldithio)butanamide, and 2-(maleimide)ethyl-N-(11-hexaethylene oxide-undecyldithio)acetamide SAM functionalized Au substrates.The neuronalattachmentand out- growth have been evaluated in embryonic mouse hippocampal neuron cultures up to 14 daysin vitro. Our results show that differences in the cell morphologies were observed on the surfaces modified with various SAMs, despite the minor differences in chemical composition identified using standard characteriza- tion tools.These different cell morphologies can most probably be explained when investigating the effect of a given SAM layer on the adsorption of proteins present in the culture medium. More likely, it is the ratio between the specific PA22-2 adsorption and nonspecific medium protein adsorption that controls the cellular morphology. Large amounts of adsorbed medium proteins could screen the PA22-2 sites required for cellular attachment. Introduction Neuronal adhesion on solid-state surfaces plays the central role in the development of cell-based biosensors and implan- table medical devices. 1,2 In such devices, the interface chem- istry allowscreation ofa biomimetic chip surface which sustains normal neuronal viability and growth without inter- fering with the system’s functionality. 1-3 The first step in creating a biomimetic surface is the devel- opment of suitable surface coatings allowing efficient cou- pling of biologically active molecules on the device. Such coatings can be obtained through self-assembly of alkanethiol monolayers (SAMs). 4-9 These SAMs are easy to prepare and are known to form well-ordered thin films onto gold surfaces. 10-15 In particular, this is a key aspect for the devel- opment of sensor arrays detecting extracellularly electrical activities of electrogenetic cells. 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Langmuir 2003, 19, 4351–4357. Published on Web 3/13/2009 © 2009 American Chemical Society DOI: 10.1021/la802217r Langmuir 2009, 25(8), 4564–4570 4564