The ability to probe an interface beneath a layer of living cells in vitro without the need for labeling and fixation has the potential to unlock key questions in cell biology and biointerfacial phenomena. In particular fibril formation within the first steps of cell adhesion has been has been identified to play a key role for cell-implant interactions, for microbial biofilm formation on industrial surfaces, or for understanding basic phenomena in the context bacterial infections mediated through fibrillar assemblies. In this contribution we show how the technique of second-harmonic-generation microscopy and sum-frequency-generation spectroscopy can be utilized to detect ordered structures within tissue and at interphases between substrates and living, adherent cells. These were detected within the first steps of cell adhesion in real-time and in vitro with no labeling and/or fixation required.

[1] Diesner, M.-O.; Welle, A.; Kazanci, M.; Kaiser, P.; Spatz, J.; Koelsch, P., In vitro observation of dynamic ordering processes in the extracellular matrix of living, adherent cells. Biointerphases 2011, 6, (4), 171-179.

[2] Diesner, M. O.; Howell, C.; Kurz, V.; Verreault, D.; Koelsch, P., In Vitro Characterization of Surface Properties Through Living Cells. J. Phys. Chem. Lett. 2010, 1, (15), 2339-2342.

[3] Howell, C.; Diesner, M. O.; Grunze, M.; Koelsch, P., Probing the Extracellular Matrix with Sum-Frequency-Generation Spectroscopy. Langmuir 2008, 24, (24), 13819-13821.