Thipvaree WangchareansakChak SangmaPaiboon NgernmeesriArunee ThitithanyanontPeter A. LieberzeitUniversitat WienKasetsart UniversityMahidol University2018-10-192018-10-192013-08-01Analytical and Bioanalytical Chemistry. Vol.405, No.20 (2013), 6471-647816182650161826422-s2.0-84880787228https://repository.li.mahidol.ac.th/handle/20.500.14594/31263N-Acetylglucosamine (GlcNAc) is a natural ligand that interacts with the binding sites of wheat germ agglutinin (WGA) lectin. For immobilization, GlcNAc was linked to p-nitrophenol, and the nitro group was reduced and then bound to cysteine via two-step synthesis. Scanning tunneling microscopy studies revealed proper immobilization of the ligand on the gold surface of a quartz crystal microbalance (QCM) via the cysteine S-H bond as well as binding between GlcNAc and WGA. QCM measurements revealed that maximum sensitivity towards WGA can only be achieved when co-immobilizing one part ligand and 5,000 parts cysteine for steric reasons, because it allows binding of a protein monolayer on the surface. Langmuir-type treatment of the binding isotherm suggests two different binding ranges for WGA and the GlcNAc monolayer, because at concentrations of WGA below 1 μm the Gibbs energy for the binding process is one third higher than that at concentrations above this value. The same systems can be transferred to first proof-of-concept measurements with different strains of influenza A virus (H5N3, H5N1, H1N3) because GlcNAc is part of the oligosaccharide ligand responsible for the first binding step. Thus, it constitutes both a suitable tool for rapid analysis and the basis for future theoretical calculations of ligand-virus interactions. © 2013 Springer-Verlag Berlin Heidelberg.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyChemistryArticleSCOPUS10.1007/s00216-013-7057-0