Label-free evaluation of carbon nanoparticles in Layer-by-Layer self-assembled enzyme-based biosensors

摘要

The immobilization of biomolecules and the enhancement of the electron transfer are important factors regarding the performances of the enzyme-based biosensors. Layer-by-layer (LbL) strategies can be effectively used to reduce diffusion time of analytes and improve analyte access to the reaction sites, as well a minimizing biomolecule denaturation. In this work, glucose oxidase (GOx) was incorporated in a multilayer film on a gold electrode. Prior the LbL formation, the Au surface was modified with a film of conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT), by electropolymerization. Multilayer films containing the enzyme and nitrogen doped graphene (NG) dispersed in the biocompatible positively-charged polymer chitosan {chit~+(NG+GOx)}, together with the negatively charged poly(styrene sulfonate), PSS~-, were assembled and evaluated using different methods. The biosensor response toward glucose was linear in the range of 0.2-1.5 mM,with a sensitivity of 128± 4 μA cm~(-2) mM~(-1) and a detection limit of 94.3 ±8.9 μM. The biosensor maintained its stability for two weeks. The {chit~+(NG+GOx)/PSS~-} bilayer-based biosensor was used successfully for glucose detection in plant extracts.