Electron Hopping Across Hemin‐Doped Serum Albumin Mats on Centimeter‐Length Scales

Exploring long‐range electron transport across protein assemblies is a central interest in both the fundamental research of biological processes and the emerging field of bioelectronics. This work examines the use of serum‐albumin‐based freestanding mats as macroscopic electron mediators in bioelectronic devices. In particular, this study focuses on how doping the protein mat with hemin improves charge‐transport. It is demonstrated that doping can increase conductivity 40‐fold via electron hopping between adjacent hemin molecules, resulting in the highest measured conductance for a protein‐based material yet reported, and transport over centimeter length scales. The use of distance‐dependent AC impedance and DC current–voltage measurements allows the contribution from electron hopping between adjacent hemin molecules to be isolated. Because the hemin‐doped serum albumin mats have both biocompatibility and fabrication simplicity, they should be applicable to a range of bioelectronic devices of varying sizes, configurations, and applications.