Incorporation of single-walled carbon nanotubes into ferrocene-modified linear polyethylenimine redox polymer films.

In this study, we describe the effects of incorporating single-walled carbon nanotubes (SWNTs) into redox polymer-enzyme hydrogels. The hydrogels were constructed by combining the enzyme glucose oxidase with a redox polymer (Fc-C(6)-LPEI) in which ferrocene was attached to linear poly(ethylenimine) by a six-carbon spacer. Incorporation of SWNTs into these films changed their morphology and resulted in a significant increase in the enzymatic response at saturating glucose concentrations (3 mA/cm(2)) as compared to films without SWNTs (0.

High-sensitivity amperometric biosensors based on ferrocene-modified linear poly(ethylenimine).

Amperometric biosensors for glucose and hydrogen peroxide have been built by immobilizing glucose oxidase (GOX) and horseradish peroxidase (HRP) in cross-linked films of ferrocene-modified linear poly(ethylenimine). At pH 7, the glucose sensors generated limiting catalytic current densities of 1.2 mA/cm2.

Effects of electrolyte and pH on the behavior of cross-linked films of ferrocene-modified poly(ethylenimine).

Ferrocene redox polymers based on the coupling of ferrocenecarboxaldehyde to both linear and branched poly(ethylenimine) (PEI) have been prepared to investigate the effects of pH, electrolyte, and cross-linking on electron charge transport and film swelling. The redox behavior of both ferrocene-modified linear PEI and ferrocene-modified branched PEI was investigated by cyclic voltammetry, while electron diffusion coefficients reported for PEI-based redox polymers were determined by electrochemical impedance spectroscopy. In phosphate solutions at pH>7, cross-linked films of both redox polymers exhibited multiple redox wave behavior and were unstable.

Amperometric biosensors based on redox polymer-carbon nanotube-enzyme composites.

Based on their size and unique electrical properties, carbon nanotubes offer the exciting possibility of developing ultrasensitive, electrochemical biosensors. In this study, we describe the construction of amperometric biosensors based on the incorporation of single-walled carbon nanotubes modified with enzyme into redox polymer hydrogels. The composite films were constructed by first incubating an enzyme in a single-walled carbon nanotube (SWNTs) solution and then cross-linking within a poly[(vinylpyridine)Os(bipyridyl)(2)Cl(2+/3+)] polymer film.