Extended-range glucose biosensor via layer-by-layer assembly incorporating gold nanoparticles.

We report on a glucose oxidase (GOx)/polyelectrolyte (PE)/gold nanoparticle (AuNP) multilayer films that can be utilized as efficient glucose biosensors by layer-by-layer self-assembly method. Electrochemical impedance spectroscopy (EIS) and UV-visible spectroscopy were adopted to monitor the regular growth of the multilayer films. The role of gold nanoparticles integrated in the multilayer films not only increase the amount and activity of GOx, but also significantly improve the electron-transfer characteristics of the films. The performance of the multilayer films for sensing glucose could be tailored by controlling the gold nanoparticles loading in the film and the number of layers. A biosensor constructed by four poly(dimethyldiallylammonium chloride) (PDDA)/AuNP/PDDA/GOx multilayer films exhibited a wide linear calibration range from 0 to 60.0 mM with the detection limit of 3.0 microM for the detection of glucose. The dynamic range can be extended up to 120 mM. The biosensor has good stability and reproducibility.