Covalent binding of biological samples to solid supports for scanning probe microscopy in buffer solution

• Published in: Biophysical journal Vol. 65; no. 6; pp. 2437 - 2446
• Main Authors: Karrasch, S., Dolder, M., Schabert, F., Ramsden, J., Engel, A.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.12.1993; Biophysical Society
• Subjects: Azides; Biological and medical sciences; Biopolymers - analysis; Buffers; Cross-Linking Reagents; Fundamental and applied biological sciences. Psychology; Indicators and Reagents; Intermolecular phenomena; Microscopy - methods; Miscellaneous; Molecular biophysics; Solutions; Succinimides; Ultraviolet Rays; Covalent bond; Chemical modification; Biological macromolecule; Solid phase; Intermediary filament; Glass
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1016/S0006-3495(93)81327-4

Scanning force microscopy allows imaging of biological molecules in their native state in buffer solution. To this end samples have to be fixed to a flat solid support so that they cannot be displaced by the scanning tip. Here we describe a method to achieve the covalent binding of biological samples to glass surfaces. Coverslips were chemically modified with the photoactivatable cross-linker N-5-azido-2-nitrobenzoyloxysuccinimide. Samples are squeezed between derivatized coverslips and then cross-linked to the glass surface by irradiation with ultraviolet light. Such samples can be imaged repeatedly by the scanning force microscope without loss of image quality, whereas identical but not immobilized samples are pushed away by the stylus.