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Remote opto‐acoustic probing of single‐cell adhesion on metallic surfaces
Author(s) -
Abi Ghanem Maroun,
Dehoux Thomas,
Zouani Omar F.,
Gadalla Atef,
Durrieu MarieChristine,
Audoin Bertrand
Publication year - 2014
Publication title -
journal of biophotonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 66
eISSN - 1864-0648
pISSN - 1864-063X
DOI - 10.1002/jbio.201300098
Subject(s) - materials science , femtosecond , acoustic microscopy , acoustic impedance , optoelectronics , sapphire , picosecond , ultrashort pulse , optics , laser , ultrasonic sensor , microscopy , acoustics , physics
The reflection of picosecond ultrasonic pulses from a cell‐substrate interface is used to probe cell‐biomaterial adhesion with a subcell resolution. We culture monocytes on top of a thin biocompatible Ti metal film, supported by a transparent sapphire substrate. Low‐energy femtosecond pump laser pulses are focused at the bottom of the Ti film to a micron spot. The subsequent ultrafast thermal expansion launches a longitudinal acoustic pulse in Ti, with a broad spectrum extending up to 100 GHz. We measure the acoustic echoes reflected from the Ti‐cell interface through the transient optical reflectance changes. The time‐frequency analysis of the reflected acoustic pulses gives access to a map of the cell acoustic impedance Z c and to a map of the film‐cell interfacial stiffness K simultaneously. Variations in Z c across the cell are attributed to rigidity and density fluctuations within the cell, whereas variations in K are related to interfacial intermolecular forces and to the nano‐architecture of the transmembrane bonds. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)