Switchable surfaces cell adhesion

Beyond the examples discussed above, which use the synthetic polymer block of bioconjugates to suppress cell adhesion, other selective polymer functions can be exploited, for example, to generate switchable surfaces modifications. 

Another typical photoresponsive material for preparation of switchable surfaces is the spiropyran-merocyanine system. The spiropyran isomerizes to zwitterionic merocyanine conformation by UV exposure, and the reverse reaction can be triggered by irradiation with visible light as well as azobenzene. The changes in hydrophilic/hydrophobic properties through the isomerization of spiropyran groups also enable the control of cell adhesion/ detachment. Edahiro et al. reported photoresponsive cell culture substrates grafted... 

FIGURE 12.16 Schematic representation of the electrically switchable surface, (a) The surface is composed by an RGD and EG6-sulfonate mixed SAM and (b) by an RGD and EG6-ammonium mixed SAM. The two portions are able to switch from cell adhering to cell repellent in response to a potential applied. A positive potential of -E0.3 V will determine the attachment of cells in (a) while a negative potential of —0.3 V will determine the adhesion of cells in (b) [220]. 

Wischerhoff, E., Uhlig, K., Lankenau, A., Bomer, H. G., Laschewsky, A., Duschl, C., et al. (2008). Controlled cell adhesion on PEG-based switchable surfaces. Angewandte Chemie International Edition in English, 47, 5666-5668. 

Depending on the application, the surface of the biomaterial should promote cell adhesion (e.g., in an implant) or promote cell detachment (e.g., in cell sheet engineering) (Gil and Hudson, 2004 Roy et al., 2010). Responsive surfaces with cell adhesive properties which are switchable in response to an external stimulus have been extensively applied in the design of smart systems for TE. 

Wischerhoff, E., Uhlig, K., Lankenau, A. et al. (2008) Controlled cell adhesion on PEG-based switchable surfaces. 

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