Proton transportation is ubiquitous in biological signaling as well as enabled a broad range of modern device components. However, proton conductor using tunable, controllable and mass producible biological material is not yet developed for in vivo application to interface biological system. Here, we demonstrate anisotropic proton transport in the artificially aligned collagen fiber network, which is mimicking the nematic structure of the muscle fiber to show that aligned collagen can assist biological signaling as a protonic highway. Artificially aligned nematic collagen fiber network is synthesized by “grow-and-snap” method, which produces 94.2% of collagen fiber is aligned along the fluid streamline (± 10º), and 82.3% of collagen fibril is aligned along the direction of the fiber (± 10º). We demonstrate that proton conduction in nematic collagen network is Grotthuss hopping along the backbone of tropocollagen chain according to the measurement of the activation energy of the proton transportation (~ 0.19 eV) and proton conduction along the tropocollagen chain result in the surface-charge mediated two-dimensional transport, which is generally observed in the nanofluidic channels. According to the fiber orientation dependent proton conduction measurement, anisotropic proton transportation is found due to the structural anisotropy and horizontally aligned collagen fiber network exhibited higher conductance over vertically aligned collagen fiber. The understanding of the mechanism of collagen assistance to proton transport may build up a theoretical basis for further development of therapy method to cure wound-induced proton-transfer disability.
Project end date: 01/30/19