Controlling solubility of polymeric anions in supramolecular assemblies with poly(aniline) for microsensors and actuators in human tissue

Hanstein, S., Martinez-Bonastre, A., Nestler, U. and Bartlett, P.N. (2007) Controlling solubility of polymeric anions in supramolecular assemblies with poly(aniline) for microsensors and actuators in human tissue. Sensors and Actuators B: Chemical, 125 (1), 284-300. (doi:10.1016/j.snb.2007.02.015).

Abstract

The supramolecular assembly of poly(aniline) and poly(vinylsulfonate) (PAni/PVS) represents a particularly suitable catalytic material for oxidation of Vitamin C in sensor applications. PAni/PVS assemblies were prepared on platinum at increasing deoxygenation levels (LD ? MD ? HD) and in two thickness sizes of 2 ?m (thick) and 200 nm (thin). Thick HD disks with diameters of 500 ?m and 2 ?m were stable over 90 min in a stirred buffer solution at pH 7 containing 300 ?M Vitamin C. Stirring stability was lost after storage in air, but not after storage under argon. In MD disks PVS was partly lost after 3 h exposure to unstirred neutral buffer solution. Loss could be significantly reduced by oxidative enforcement with ferulic acid (F), a precursor of plant lignin. Application of elliptical F-PAni/PVS microelectrodes with diameters of 20 ?m × 30 ?m in brain parenchyma of rats showed surprisingly weak influence of intraperitoneal Vitamin C injections on the brain tissue level of Vitamin C. After 3 h of tissue exposure poly(aniline) redox activity in acidic solution decreased slightly. Factors which caused enhanced PVS solubility are discussed in detail.

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Contributors

Author: P.N. Bartlett

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