Molecular Mechanisms and Enhancement of Piezoelectricity in the M13 Virus

Understanding the structure and function of bioelectric materials is challenging due to the complex nature of biomaterials and a lack of appropriate tools. The precisely defined structures and genetic tunability of viruses provide an excellent model system to investigate bioelectrical behavior in biomaterials. This study presents the molecular mechanisms of piezoelectricity in the M13 bacteriophage (phage) under various mechanical stresses for bio-piezoelectric generation. A computational approach is used to calculate the piezoelectric tensors of the M13 phage and quantify its direction-dependent dipole moments. By computationally designing negatively charged residues on the phage surface, the surface charge density is enhanced to 16.7 mu C cm-2. Using genetic engineering, phages are experimentally designed with different charges and tail structures to create model phage nanostructures, including individual phages, vertically standing phage films, and horizontally aligned phage films. Their vertical, horizontal, and shear-mode piezoelectric properties are then measured using scanning probe microscopy techniques. The resulting phage-based piezoelectric energy generators exhibit an effective piezoelectric coefficient of 15.4 pm V-1 and a power density of 4.2 mu W cm-2. This phage-based bioengineering approach provides a versatile platform for investigating fundamental mechanisms of bioelectricity and designing bioelectric materials for applications in energy harvesting, biomemory, and biosensors. A comprehensive understanding of the molecular mechanisms of piezoelectricity in the M13 virus is demonstrated. Bio-piezoelectricity is manifested by directional-dependent dipole moments of the protein and can be manipulated by surface charge genetic engineering. This bio-piezoelectricity broadens the horizons for designing and producing bioelectrical materials and energy systems. image