Highly sensitive phenolic biosensor based on magnetic polydopamine-laccase-Fe3O4 bionanocomposite

Abstract New polydopamine (PDA)-laccase (Lac)-Fe 3 O 4 magnetic polymeric bionanocomposites (MPBNCs) were prepared through one-pot Lac-catalyzed oxidation of dopamine in an aqueous suspension containing Lac, magnetic Fe 3 O 4 nanoparticles and dopamine. A PDA-Lac-Fe 3 O 4 /Au electrode was prepared by facile and efficient magnetic separation/immobilization of the MPBNCs on a magnetic Au electrode for biosensing of hydroquinone (HQ), giving a sensitivity of 374 μA mmol −1  L cm −2 , a limit of detection of 30 nmol L −1 , as well as good selectivity and stability. The biosensing electrode was also used for HQ analysis in real sample matrices with satisfactory results.