Monitoring of glass derivatization with pulsed force mode atomic force microscopy

• Published in: Microscopy research and technique 2004-11, Vol.65 (4-5), p.246-251
• Main Authors: Ebner, Andreas, Kienberger, Ferry, Stroh, Cordula M., Gruber, Hermann J., Hinterdorfer, Peter
• Format: Article
• Language: English
• Subjects: Adhesiveness; atomic force microscopy; glass; Glass - chemistry; Microscopy, Atomic Force - methods; poly(ethylene glycol); Polyethylene Glycols; Silanes - chemistry; silanization; Surface Properties
• ISSN: 1059-910X; 1097-0029
• DOI: 10.1002/jemt.20124

Non‐specific adsorption of proteins at solid/liquid interfaces is a major problem in the use of synthetic biomaterials and in ultrasensitive detection methods. Grafting surfaces with a dense layer of poly(ethylene glycol) (PEG) or other polymers is a most widely used strategy to solve this task. While such modified surfaces have been characterized by their ability to resist protein adsorption, the polymer layers themselves have rarely been studied in fine detail. Atomic force microscopy (AFM) using the pulsed force mode (PFM), is an ideal technique to investigate structural features and physiochemical properties of surfaces because topology and adhesion are simultaneously detected with high lateral resolution. In the present study, PFM‐AFM was applied to thoroughly characterize different stages of glass derivatization, up to the formation of a dense PEG layer. Lateral inhomogeneities in topology and/or adhesion were observed at all stages before PEG attachment. The covalently bound PEG, however, was seen to form a densely packed monolayer with maximal thickness, smooth surface, and weak adhesion. Thus, PFM‐AFM appears to be a valuable tool for the characterization of protein‐repelling surfaces in solution. Microsc. Res. Tech. 65:246–251, 2004. © 2005 Wiley‐Liss, Inc.