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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.


Ternary complex formation with chemomechanical polymer I: co-complexation with metal ions.
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f27-sensors-07-01578: Ternary complex formation with chemomechanical polymer I: co-complexation with metal ions.

Mentions: Analytes which interact not directly with supramolecular binding sites of a polymer can be brought into action, if another, strongly interacting effector molecule exhibits strong binding both to the polymer and to the analyte of interest (Scheme 13) [71]. The ethylenediamine units in polymer I allow to bind strongly transition metal ions such as Cu2+, which in turn are known to associate effectively with e.g. aminoacids or peptides; with a chemomechanical polymer this can lead to sizeable volume expansions (Figure 10) [72]. Related co-complexations have been used successfully already for other sensor applications [73]. The additional interaction groups of polymer I (Scheme 13) provide for additional discrimination with the aminoacid side groups, which is visible in swelling differences between different peptides (Scheme 14). With some special chelating agents the expansions reach a record 475 % on top of the swelling produced by the metal ion itself [71]. Removal of the metal cations by decomplexing agents leads to a reversible contraction of the swollen gel as function of the decomplexing agent chelating strength. It should be noted that analytes such as peptides alone lead to no measurable size changes of the gel, which illustrates again with a chemomechanical polymer the unique feature of a macroscopic logical AND gate.


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

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

Ternary complex formation with chemomechanical polymer I: co-complexation with metal ions.
© Copyright Policy
Related In: Results  -  Collection

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

f27-sensors-07-01578: Ternary complex formation with chemomechanical polymer I: co-complexation with metal ions.
Mentions: Analytes which interact not directly with supramolecular binding sites of a polymer can be brought into action, if another, strongly interacting effector molecule exhibits strong binding both to the polymer and to the analyte of interest (Scheme 13) [71]. The ethylenediamine units in polymer I allow to bind strongly transition metal ions such as Cu2+, which in turn are known to associate effectively with e.g. aminoacids or peptides; with a chemomechanical polymer this can lead to sizeable volume expansions (Figure 10) [72]. Related co-complexations have been used successfully already for other sensor applications [73]. The additional interaction groups of polymer I (Scheme 13) provide for additional discrimination with the aminoacid side groups, which is visible in swelling differences between different peptides (Scheme 14). With some special chelating agents the expansions reach a record 475 % on top of the swelling produced by the metal ion itself [71]. Removal of the metal cations by decomplexing agents leads to a reversible contraction of the swollen gel as function of the decomplexing agent chelating strength. It should be noted that analytes such as peptides alone lead to no measurable size changes of the gel, which illustrates again with a chemomechanical polymer the unique feature of a macroscopic logical AND gate.

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.