Preparation of Gradient Surfaces by Using a Simple Chemical Reaction and Investigation of Cell Adhesion on a Two-Component Gradient

• Published in: Chemistry : a European journal 2013-04, Vol.19 (18), p.5609-5616
• Main Authors: Lee, Jeongwook, Choi, Inseong, Yeo, Woon-Seok
• Format: Article
• Language: English
• Subjects: Amines; Animals; Cell adhesion; Cell adhesion & migration; Cell Adhesion - physiology; Chemical reactions; Chemistry; Fibronectins - chemistry; Gold - chemistry; gradient surfaces; Ligands; Mass spectrometry; Mice; Monolayers; NIH 3T3 Cells; Oligopeptides - chemistry; Peptide Fragments - chemistry; Peptides; Proteins - analysis; Self-assembled monolayers; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Strategy; synergistic effects
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201203215

This article describes a simple method for the generation of multicomponent gradient surfaces on self‐assembled monolayers (SAMs) on gold in a precise and predictable manner, by harnessing a chemical reaction on the monolayer, and their applications. A quinone derivative on a monolayer was converted to an amine through spontaneous intramolecular cyclization following first‐order reaction kinetics. An amine gradient on the surface on a scale of centimeters was realized by modulating the exposure time of the quinone‐presenting monolayer to the chemical reagent. The resulting amine was used as a chemical handle to attach various molecules to the monolayer with formation of multicomponent gradient surfaces. The effectiveness of this strategy was verified by cyclic voltammetry (CV), matrix assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry (MS), MS imaging, and contact‐angle measurements. As a practical application, cell adhesion was investigated on RGD/PHSRN peptide/peptide gradient surfaces. Peptide PHSRN was found to synergistically enhance cell adhesion at the position where these two ligands are presented in equal amounts, while these peptide ligands were competitively involved in cell adhesion at other positions. This strategy of generating a gradient may be further expandable to the development of functional gradient surfaces of various molecules and materials, such as DNA, proteins, growth factors, and nanoparticles, and could therefore be useful in many fields of research and practical applications. Getting the balance right: A simple chemical reaction on self‐assembled monolayers (SAMs) on gold allows gradient surfaces of various molecules. Investigation of cell adhesion behavior on two‐component gradients shows that the synergistic effect is observed only when the two ligands exist in equal amounts (see figure).