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Chemomechanical Polymers as Sensors and Actuators for Biological and Medicinal Applications.

Schneider HJ, Kato K, Strongin RM - Sensors (Basel) (2007)

Bottom Line: Two different effector molecules can induce motions as functions of their concentration, thus representing a logical AND gate.Another principle relies on the fast formation of covalent bonds between an effector and the chemomechanical polymer.The speed of the responses can significantly increase by increasing the surface to volume ratio of the polymer particles.

View Article: PubMed Central - PubMed

Affiliation: FR Organische Chemie der Universität des Saarlandes, D-66041 Saarbrücken, Germany.

ABSTRACT
Changes in the chemical environment can trigger large motions in chemomechanical polymers. The unique feature of such intelligent materials, mostly in the form of hydrogels, is therefore, that they serve as sensors and actuators at the same time, and do not require any measuring devices, transducers or power supplies. Until recently the most often used of these materials responded to changes in pH. Chemists are now increasingly using supramolecular recognition sites in materials, which are covalently bound to the polymer backbone. This allows one to use a nearly unlimited variety of guest (or effector) compounds in the environment for a selective response by automatically triggered size changes. This is illustrated with non-covalent interactions of effectors comprising of metal ions, isomeric organic compounds, including enantiomers, nucleotides, aminoacids, and peptides. Two different effector molecules can induce motions as functions of their concentration, thus representing a logical AND gate. This concept is particularly fruitful with effector compounds such as peptides, which only trigger size changes if, e.g. copper ions are present in the surroundings. Another principle relies on the fast formation of covalent bonds between an effector and the chemomechanical polymer. The most promising application is the selective interaction of covalently fixed boronic acid residues with glucose, which renders itself not only for sensing, but eventually also for delivery of drugs such as insulin. The speed of the responses can significantly increase by increasing the surface to volume ratio of the polymer particles. Of particular interest is the sensitivity increase which can be reached by downsizing the particle volume.

No MeSH data available.


Kinetics of expansion and desorption (action of AMP on polymer I, least square fit to first order equation. Schneider, H. J.; Liu, T. J.; Lomadze, N. Molecular recognition in a supramolecular polymer system translated into mechanical motion. Copyright Wiley-VCH Verlag GmbH & Co. [39a].
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f2-sensors-07-01578: Kinetics of expansion and desorption (action of AMP on polymer I, least square fit to first order equation. Schneider, H. J.; Liu, T. J.; Lomadze, N. Molecular recognition in a supramolecular polymer system translated into mechanical motion. Copyright Wiley-VCH Verlag GmbH & Co. [39a].

Mentions: The speed of volume changes are essentially a function of the effector diffusion into the gels, as described by Fick's laws. It has been shown that expansion of xanthan-chitosan-derived gels upon pH changes seems to be mainly controlled by the diffusion of mobile ions, except that at pH values below 10 the degree of ionization during swelling also may affect the swelling rate [55,56]. Figure 2 illustrates that with the PMMA derived polymer I the kinetics of both expansion and the fully reversible contractions follow pseudo first–order equations, the same holds for the corresponding ab- and desorption of the effectors [39].


Chemomechanical Polymers as Sensors and Actuators for Biological and Medicinal Applications.

Schneider HJ, Kato K, Strongin RM - Sensors (Basel) (2007)

Kinetics of expansion and desorption (action of AMP on polymer I, least square fit to first order equation. Schneider, H. J.; Liu, T. J.; Lomadze, N. Molecular recognition in a supramolecular polymer system translated into mechanical motion. Copyright Wiley-VCH Verlag GmbH & Co. [39a].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3814870&req=5

f2-sensors-07-01578: Kinetics of expansion and desorption (action of AMP on polymer I, least square fit to first order equation. Schneider, H. J.; Liu, T. J.; Lomadze, N. Molecular recognition in a supramolecular polymer system translated into mechanical motion. Copyright Wiley-VCH Verlag GmbH & Co. [39a].
Mentions: The speed of volume changes are essentially a function of the effector diffusion into the gels, as described by Fick's laws. It has been shown that expansion of xanthan-chitosan-derived gels upon pH changes seems to be mainly controlled by the diffusion of mobile ions, except that at pH values below 10 the degree of ionization during swelling also may affect the swelling rate [55,56]. Figure 2 illustrates that with the PMMA derived polymer I the kinetics of both expansion and the fully reversible contractions follow pseudo first–order equations, the same holds for the corresponding ab- and desorption of the effectors [39].

Bottom Line: Two different effector molecules can induce motions as functions of their concentration, thus representing a logical AND gate.Another principle relies on the fast formation of covalent bonds between an effector and the chemomechanical polymer.The speed of the responses can significantly increase by increasing the surface to volume ratio of the polymer particles.

View Article: PubMed Central - PubMed

Affiliation: FR Organische Chemie der Universität des Saarlandes, D-66041 Saarbrücken, Germany.

ABSTRACT
Changes in the chemical environment can trigger large motions in chemomechanical polymers. The unique feature of such intelligent materials, mostly in the form of hydrogels, is therefore, that they serve as sensors and actuators at the same time, and do not require any measuring devices, transducers or power supplies. Until recently the most often used of these materials responded to changes in pH. Chemists are now increasingly using supramolecular recognition sites in materials, which are covalently bound to the polymer backbone. This allows one to use a nearly unlimited variety of guest (or effector) compounds in the environment for a selective response by automatically triggered size changes. This is illustrated with non-covalent interactions of effectors comprising of metal ions, isomeric organic compounds, including enantiomers, nucleotides, aminoacids, and peptides. Two different effector molecules can induce motions as functions of their concentration, thus representing a logical AND gate. This concept is particularly fruitful with effector compounds such as peptides, which only trigger size changes if, e.g. copper ions are present in the surroundings. Another principle relies on the fast formation of covalent bonds between an effector and the chemomechanical polymer. The most promising application is the selective interaction of covalently fixed boronic acid residues with glucose, which renders itself not only for sensing, but eventually also for delivery of drugs such as insulin. The speed of the responses can significantly increase by increasing the surface to volume ratio of the polymer particles. Of particular interest is the sensitivity increase which can be reached by downsizing the particle volume.

No MeSH data available.