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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.


Weight increase compared to expansion. Values scaled per mg of wet PMMA-derived polymer I, in mg of total weight increase due to water and effector, and in mg increase due to effector alone (upper limit as estimated from absorption measurements and complexometry); volume expansion Δv (from 1 mm3 wet), average from length and width increase. Weight increase is within the error due to water content increase. Copyright Wiley-VCH Verlag GmbH & Co. [39a].
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f19-sensors-07-01578: Weight increase compared to expansion. Values scaled per mg of wet PMMA-derived polymer I, in mg of total weight increase due to water and effector, and in mg increase due to effector alone (upper limit as estimated from absorption measurements and complexometry); volume expansion Δv (from 1 mm3 wet), average from length and width increase. Weight increase is within the error due to water content increase. Copyright Wiley-VCH Verlag GmbH & Co. [39a].

Mentions: Gravimetric measurements allow one to quantify the role of water uptake and/or release. Scheme 5 shows the weight increase which accompanies effector absorption in PMMA polymer I. Independent measurements of water content before and after expansion establish that the weight increase is almost entirely due to water uptake. At the same time Scheme 5 illustrates the abovementioned water uptake by protonation and deprotonation at low and high pH. In comparison to pH = 7 there is a water content increase by a factor of f = 26±1. The swelling induced by other effectors reflects the need of these molecules inside the gel for effector solvation, leading to a expansion which goes far beyond the weight and volume increase which would be produced by the effector alone [39].


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

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

Weight increase compared to expansion. Values scaled per mg of wet PMMA-derived polymer I, in mg of total weight increase due to water and effector, and in mg increase due to effector alone (upper limit as estimated from absorption measurements and complexometry); volume expansion Δv (from 1 mm3 wet), average from length and width increase. Weight increase is within the error due to water content increase. Copyright Wiley-VCH Verlag GmbH & Co. [39a].
© Copyright Policy
Related In: Results  -  Collection

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

f19-sensors-07-01578: Weight increase compared to expansion. Values scaled per mg of wet PMMA-derived polymer I, in mg of total weight increase due to water and effector, and in mg increase due to effector alone (upper limit as estimated from absorption measurements and complexometry); volume expansion Δv (from 1 mm3 wet), average from length and width increase. Weight increase is within the error due to water content increase. Copyright Wiley-VCH Verlag GmbH & Co. [39a].
Mentions: Gravimetric measurements allow one to quantify the role of water uptake and/or release. Scheme 5 shows the weight increase which accompanies effector absorption in PMMA polymer I. Independent measurements of water content before and after expansion establish that the weight increase is almost entirely due to water uptake. At the same time Scheme 5 illustrates the abovementioned water uptake by protonation and deprotonation at low and high pH. In comparison to pH = 7 there is a water content increase by a factor of f = 26±1. The swelling induced by other effectors reflects the need of these molecules inside the gel for effector solvation, leading to a expansion which goes far beyond the weight and volume increase which would be produced by the effector alone [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.