Surface Functionalization with Carboxylic Acids by Photochemical Microcontact Printing and Tetrazole Chemistry

In this paper, we show that carboxylic acid-functionalized molecules can be patterned by photochemical microcontact printing on tetrazole-terminated self-assembled monolayers. Upon irradiation, tetrazoles eliminate nitrogen to form highly reactive nitrile imines, which can be ligated with several different nucleophiles, carboxylic acids being the most reactive. As a proof of concept, we immobilized trifluoroacetic acid to monitor the reaction with X-ray photoelectron spectroscopy. Moreover, we also immobilized peptides and fabricated carbohydrate-lectin as well as biotin-streptavidin microarrays using this method. Surface-patterning was demonstrated by fluorescence microscopy and time-of-flight secondary ion mass spectrometry.