Switchable surfaces

Mrksich and coworkers [150] demonstrated even more sophisticated switchable surfaces where cells could be sequentially released and reattached. A SAM that... 

Figure 1.29 Scheme of sophisticated switchable surfaces where cells could be sequentially released and reattached. A self-assembled monolayer, using an O-silyl hydroquinone as the cleavable molecule, allows for the release and reattachment of cells onto a surface. (Reprinted with permission from Ref [150]. 2003 American Chemical Society.)... 

Minko S, Stamm M, Goreshnik E, Usov D, Sidorenko A. Environmentally responsive polymer brush layers for switchable surface properties. Pol3mi Mater Sci Eng 2000 83 533-534. 

Figure 2 Pass Ale types ofpolymers based upon catenane architecures A Linear mechanically-linked polymers B mechanically cross-linked polymers C stars with a flexible, potentially switchable, catenane core D combs with catenarw linkages E main chain catenanes with switchable surface properties F highly mechani-cally-crosslinked networks G poly- or [n]catenanes. Only examples of types A and F have thus far been prepared...

Thermoresponsive polymers based on oligo(ethylene glycol) acrylates or methacrylates can be easily prepared by atom transfer radical polymerization under straightforward experimental conditions (i.e. in bulk or in ethanol solution and in the presence of commercially available catalysts). Thus, these stimuli-responsive macromolecules can be exploited for preparing a wide range of smart advanced materials such as thermoreversible hydrogels, thermoresponsive block-copolymer micelles and switchable surfaces. Hence, some of the results... 

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. 

Electrochemistry of dithienylethenes and their application in electropolymer modified photo- and redox switchable surfaces 130BC233. 

On the other hand, cells and proteins exhibit space- and time-dependent dynamic changes in their conformations and functionalities in the human body. Since the 1990s, dynamic switchable surfaces have been comprehensively studied in order to control the biomolecular dynamics by modification with smart polymers [6], which show changes in their conformations and properties in response to external stimuli. Among them, thermo-responsive poly(AT-isopropylacrylamide) (PNlPA/ m) is one of the most successful models to control the interaction between biomolecules and the grafted substrates by temperature... 

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... 

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