Seed-mediated synthesis of polyaniline/Au nanocomposite and its application for a cholesterol biosensor

The polyaniline (PANI)/Au nanocomposite was successfully fabricated through a seed-mediated strategy. And the hybrid nanostructure evaluated as a new material for cholesterol biosensor was demonstrated. UV–vis spectra proved the production of conductive PANI and the increase of the particle size of the Au nano-seeds. Scanning electron microscopic measurements displayed that the synthesized PANI/Au exhibited a spherical structure with dimensions of about 300 nm in diameter. Energy dispersive X-ray spectrogram demonstrated the ingredient of the composite. Cyclic voltammetry and electrochemical impedance spectroscopy investigation of the PANI/Au modified electrode indicated the good conductivity of the composite. Direct electron transfer of cholesterol oxidase (ChOx) was obtained in pH 7.0 phosphate buffer solution when ChOx was further immobilized on the PANI/Au modified electrode. This result showed that the PANI/Au nanocomposite was a good candidate for the development of the cholesterol biosensor. The biosensor displayed a response time of 3 s. Some common interferents like glucose and ascorbic acid did not cause interference due to the use of a low operating potential.

► Polyaniline/Au nanocomposite was fabricated through a seed-mediated strategy.
► Direct electrochemistry of cholesterol oxidase was obtained.
► A rapid and interference-free cholesterol amperometric biosensor was developed.