Polypyrrole hydrogels

S. Brahim, D. Narinesingh, and A. Guiseppi-Elie, Polypyrrole-hydrogel composites for the construction of clinically important biosensors. Biosens. Bioelectron. 17, 53-59 (2002). 

When the conducting polymer is used as ion-to-electron transducer in the form of an intermediate layer between the electronic conductor and the ion-selective membrane it does not significantly influence the sensitivity and selectivity of the ISE, but it allows high potential stability [75]. For example, microfabricated solid-state K+-ISEs with polypyrrole as ion-to-electron transducer was found to show even better long-term potential stability than those based on a hydrogel contact [58]. The potential of the polypyrrole-based K+-ISE was slightly more sensitive to the oxygen concentration of the sample in comparison to... 

When constructing biosensors, which are to be used continuously in vivo or in situ, maintaining sensor efficiency while increasing sensor lifetime are major issues to be addressed. Researchers have attempted various methods to prevent enzyme inactivation and maintain a high density of redox mediators at the sensor surface. Use of hydrogels, sol-gel systems, PEI and carbon paste matrices to stabilize enzymes and redox polymers was mentioned in previous sections. Another alternative is to use conductive polymers such as polypyrrole [123-127], polythiophene [78,79] or polyaniline [128] to immobilize enzymes and mediators through either covalent bonding or entrapment in the polymer matrix. Application to various enzyme biosensors has been tested. 

Xiao, Y., He, L., Che, J., 2012. An effective approach for the fabrication of reinforced composite hydrogel engineered with SWNTs, polypyrrole and PEGDA hydrogel. Journal of Materials Chemistry 22, 8076—8082. 

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