Bioelectrocatalytic reactivity of myoglobin in layer-by-layer films assembled with triblock copolymer Pluronic F127

In this paper, electroactive protein myoglobin (Mb) was successfully assembled layer-by-layer with poly(ethylene oxide)100–poly(propylene oxide)65–poly(ethylene oxide)100 triblock copolymer (Pluronic) into {Pluronic/Mb}n films on solid surfaces. Quartz crystal microbalance (QCM) and cyclic voltammetry (CV) were used to monitor the film growth and characterize the films. The Mb in stable {Pluronic/Mb}n films exhibited a nearly reversible CV peak pair at −0.34 V vs. SCE for Mb heme Fe(III)/Fe(II) couple, and the films demonstrated good electrocatalytic responses to oxygen, hydrogen peroxide, and nitrite. Compared with cast Mb–Pluronic films, {Pluronic/Mb}n multilayer films showed higher fraction of electroactive protein, better controllability in film construction, and better bioelectrocatalytic performances, indicating the potential application of the films as a new type of biosensors based on the direct electrochemistry of redox proteins without using mediators. The driving forces for the assembly of {Pluronic/Mb}n films were also studied and believed to be mainly the ion–dipole interaction between positively charged groups of Mb and electronegative ether oxygen groups of nonionic Pluronic.