Layer-by-layer assembly of collagen and electroactive myoglobin

In this work, an electrochemically inert protein collagen was successfully assembled with electroactive myoglobin (Mb) into {collagen/Mb}n layer-by-layer (LbL) films on solid surfaces. UV–vis spectroscopy and cyclic voltammetry (CV) were used to confirm the film growth and characterize the films. The collagen films provided a biocompatible microenvironment for Mb, and Mb in the stable {collagen/Mb}n films showed a nearly reversible CV response for its heme Fe(III)/Fe(II) redox couple. The direct electrochemistry of Mb in the films was used to electrocatalyze the reduction of oxygen and hydrogen peroxide. The interaction between collagen and Mb under different pH conditions was also explored. Not only the positively charged Mb at pH 5.0 but also the negatively charged Mb at pH 9.0 could be assembled with collagen into {collagen/Mb}n films. This work provides a novel example to assemble LbL films with two different proteins, and may establish a foundation for fabricating the new type of biosensors based on the direct electron transfer of redox proteins with underlying electrodes.