Reversibly Photo-Modulating Mechanical Stiffness and Toughness of Bioengineered Protein Fibers.


Sun J(1)(2), Ma C(3)(2), Maity S(2), Wang F(3), Zhou Y(2)(4), Portale G(2), Göstl R(4), Roos WH(2), Zhang H(1)(3), Liu K(1)(3), Herrmann A(2)(4)(5).
Author information:
(1)Department of Chemistry, Tsinghua University, Beijing, 100084, China.
(2)Zernike Institute for Advanced Materials, Nijenborgh 4, 9747, AG, Groningen, The Netherlands.
(3)State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
(4)DWI-, Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056, Aachen, Germany.
(5)Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.


Light-responsive materials have been extensively studied due to the attractive possibility of manipulating their properties with high spatiotemporal control in a non-invasive fashion. This stimulated the development of a series of photo-deformable smart devices. However, it remained a challenge to reversibly modulate the stiffness and toughness of bulk materials. Here, we present bioengineered protein fibers and their optomechanical manipulation by employing electrostatic interactions between supercharged polypeptides (SUPs) and an azobenzene (Azo)-based surfactant. Photo-isomerization of the Azo moiety from the E- to Z-form reversibly triggered the modulation of tensile strength, stiffness, and toughness of the bulk protein fiber. Specifically, the photo-induced rearrangement into the Z-form of Azo possibly strengthened cation-π interactions within the fiber material, resulting in an around twofold increase in the fiber's mechanical performance. The outstanding mechanical and responsive properties open a path towards the development of SUP-Azo fibers as smart stimuli-responsive mechano-biomaterials.