Facile Derivatization of Glassy Carbon Surfaces by N-Hydroxysuccinimide Esters in View of Attaching Biomolecules

The reaction of N -hydroxysuccinimide (NHS) esters with freshly polished glassy carbon surfaces offers a facile and versatile method of derivatization. Surface concentrations larger than 10 - 10 mol/cm 2 can thus be easily achieved. They can be further increased when polishing is carried out in the presence of ammonia, which also improves their reproducibility. It is shown that the derivatization results from the formation of a covalent peptide linkage by reaction of the NHS ester with superficial amino groups on the glassy carbon surface. The peptide linkage is remarkably stable in time and can only be hydrolyzed in very strong basic media. 9-fluorenylmethoxycarbonyl chloride protection, followed by preparation of the NHS ester, by surface derivatization and by mild deprotection allows the grafting of a molecule that contains an amino group located remotely from the electrode surface, thus opening a route to the attachment of a large variety of biomolecules, for which NHS esters are available, in a position where their degradation should be avoided or minimized.