Vol.:(0123456789) 1 3 J Mater Sci: Mater Electron DOI 10.1007/s10854-017-7610-2 Patterning protein conjugates into organized microarrays with diphenylalanine peptide nanotubes self-assembled on graphite and gold electrode Ehsan Moini 1  · Ali A. Dadkhah 1  · Alireza Allafchian 2  · Neda Habibi 2,3   Received: 2 June 2017 / Accepted: 26 July 2017 © Springer Science+Business Media, LLC 2017 bionanostructure arrays allowing the fabrication of a vari- ety of microarrays used in practical applications. 1 Introduction Precise control of patterning and manipulation of bio- molecules in geometrically controlled arrays has proven a useful tool for developing Lab-on-a-Chip devices [1]. The nanostructures built up from biomolecules have gained attraction for assembling recognition ligands since they show versatility of chemical and biological modifcation, biocompatibility and fabrication of molecular conforma- tion with bottom-up approach [2–4]. Several biomolecules including DNA, lipids, proteins and peptides can self- assemble into highly ordered nanostructures [5, 6]. Despite promising progress in developing self-assembled nano- structures from biomolecules, they possess limitation in terms of thermal and mechanical stability. Recently, a simples peptide building blocks such as the diphenylalanine (FF) motif of the Alzheimer’s β-amyloid peptide have been introduced and received increasing attention [7–10]. Self-assembled FF-based nanostructures, especially peptide nanotubes (PNTs), have extraordinary mechanical strength and good chemical and thermal sta- bility [11, 12], which make them appealing structural ele- ments for various applications [6, 13, 14]. However, to fully exploit their potential for nanostructure fabrication and sensing devices, controlling their macroscopic organi- zation, or alignment and stability on a solid surface are needed which remains a signifcant challenge [15]. Previous studies have reported solid phase growth meth- ods of FF peptide nanostructures to overcome the draw- backs of current solution-based approaches of peptide nanofabrication. Among the solid-phase growth methods of Abstract Controlling the arrangement and organization of self-assembled peptide nanostructures is a crucial step in developing Lab-on-a-Chip devices based on biomolecular assembly. Here, we report a simple approach to achieve the vertically aligned assembly of diphenylalanine (FF) peptide by casting stock solution of FF peptide on gold and graph- ite modifed silicones. We show at the frst time the forma- tion of highly ordered interlaced arrays of vertical fower crystals and peptide nanotubes (PNTs) on thiolated gold and graphite. Furthermore, their chemical stability was investigated in PBS bufer after 3 h to gain insight into the stability of modifed electrodes upon cycling. Interestingly, a highly ordered hierarchical morphology was obtained on the substrate surface. Hierarchical morphology resembles a square lattice, dendritic forest, and three-dimensional packed arrays. The results confrmed that PNTs not only preserves its chemical stability but transform into hierarchi- cal arrays in PBS which is very benefcial for their appli- cations in bioelectrochemical and nanoelectronics devices. As an example, the signifcantly enhanced arrangement of antibody CD3 was also demonstrated at the PNTs modifed gold electrode compared to unordered modifed electrodes. The simple and mild approach described here opens a new path for the fabrication of organized self-assembled peptide * Neda Habibi ned.habibi@gmail.com 1 Chemical Engineering Department, Isfahan University of Technology, Isfahan, Iran 2 Research Institute for Nanotechnology and Advanced Materials, Isfahan University of Technology, Isfahan, Iran 3 Department of Biomedical Engineering, College of Engineering, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249-0619, USA