Polymer transducer supports

Newbury K-M, Leo D-J (2003) Linear electromechanical model of ionic polymer transducers - part I model development J Intell Mater Syst Struct 14 333-342 Nguyen XT, Goo NS, Nguyen VK, Yoo Y, Park S (2008) Design, fabrication, and experimental characterization of a flap valve IPMC micropump with a flexibly supported diaphragm. Sens Actuators A 141 640-648... 

Photoswitchable antigen/antibody (substrate/ receptor) complexes 1. Reversible immunosensors 2. Patterning of surfaces with biomaterials using antigen/antibody-biomaterial conjugates (Design of biosensor arrays, biochips) 1. Immobilization of systems on electronic transducers (electrodes, piezoelectric crystals, FET) or the assembly of biomaterials on inert supports by non-covalent interactions (eg. glass, polymers)... 

The basic requirement in biosensor development is ascribed to the successful attachment of the recognition material, a process governed by various interactions between the biological component and the sensor interface. Advanced immobilization technologies capable of depositing biologically active material onto or in close proximity of the transducer surface have been reported. In this context, the choice of a biocompatible electrode material is essential. The material surfaces (support) include almost all material tjrpes metals, ceramics, polymers, composites and carbon materials [8]. In most cases, when a native material does not meet all the requirements for... 

Many questions pertaining to membrane processes in general and ligand/membrane receptor interactions in particular can be addressed by a novel model membrane system, i.e., polymer-supported or polymer-tethered lipid bilayers [12,14], The basic structural unit for this sensor platform is the tethered lipid bilayer membrane [16] displayed in Fig. 2D. The essential architectural elements of this supramolecular assembly include the solid support, e.g., an optical or electrical transducer (device), the polymeric tether system which provides the partial covalent and, hence, very stable attachment of the whole membrane to the substrate surface, and the fluid lipid bilayer, functionalized if needed by embedded proteins. 

In general, adsorption is achieved by applying a solution of the molecule to be immobilized to a membrane or him on the sensor transducer and allowing the molecule to adsorb to the transducer over a specified time period. The membrane or film may be hydrophilic or hydrophobic or may contain ionic groups depending on the molecule to be immobilized. Various support/surface materials have been used for adsorption but the most used are silica, cellulose acetate membranes, and polymers such as PVC and polystyrene. As shown in table 8.5, adsorption is still used in the fabrication of many chemical sensors and biosensors. 

In previous sections, carbon materials serve either as sensing materials or as transducers. Many studies also use carbon-polymer composites, where carbon materials serve as both support and transducer. The polymer-coated FET discussed above is one example. Arrays of carbon black/organic polymer composite have also been demonstrated in many studies as chemiresistive vapor detectors... 

In conclusion, polymers play a versatile role in the field of chemosensors. Most interestingly, certain polymers can actively serve as sensors. This pertains to certain strongly fluorescent conjugated polymers, as pointed out above, and to polymers employed as cladding for optical fibers in evanescent wave-based sensors. Moreover, polymers are widely used as supports for transducers, which are either admixed or chemically linked to the polymer matrices. Typical examples are given in the following sections. 

The use of conducting polymers in sensor technologies involves employing the conducting polymers as an electrode modification in order to improve sensitivity, to impart selectivity, to suppress interference, and to provide a support matrix for sensor molecules [7,9,16,18,22,25,26,113-216]. All electrochemical transducer principles can also be realized with conducting-polymer-modified electrodes. The role of the conducting polymer may be active (for instance, when used as a catalytic layer, as a redox mediator, as a switch, or as a chemically modulated resistor, a so-called chemiiesistor ) or passive (for instance, when used as a matrix) [7,9,16,22,23,26,122,123,167,168,176,177]. 

Biosensors are analytical devices that are able to detect biological components. SAMs and lipid bilayers are often used as platforms for the immobilization of biosensors [532-534], but other supports, such as Si—SiOa [535-537], Ti02 [538], and polymers [539, 540], can also be used. Electrochemical biosensors [541, 542] might use potentiometric, field-effect transistor, amperometric, or impedimetric transducers. 

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