Diatom-inspired multiscale mineralization of patterned protein–polysaccharide complex structures

Abstract

Marine diatoms construct their hierarchically ordered, three-dimensional (3D) external structures called frustules through precise biomineralization processes. Recapitulating the remarkable architectures and functions of diatom frustules in artificial materials is a major challenge that has important technological implications for hierarchically ordered composites. Here, we report the construction of highly ordered, mineralized composites based on fabrication of complex self-supporting porous structures—made of genetically engineered amyloid fusion proteins and the natural polysaccharide chitin—and performing in situ multiscale protein-mediated mineralization with diverse inorganic materials, including SiO2, TiO2, and Ga2O3. Subsequently, using sugar cubes as templates, we demonstrate that 3D fabricated porous structures can become colonized by engineered bacteria and can be functionalized with highly photoreactive minerals, thereby enabling co-localization of the photocatalytic units with a bacteria-based hydrogenase reaction for a successful semi-solid artificial photosynthesis system for hydrogen evolution. Our study thus highlights the power of coupling genetically engineered proteins and polysaccharides with biofabrication techniques to generate hierarchically organized mineralized porous structures inspired by nature.

Diatom-Inspired TiO2-PANi-Decorated Bilayer Photothermal Foam for Solar-Driven Clean Water Generation

“…The enhancement of the C 1s peak is due to the presence of the C−C, CC, CN, and C−N groups in PANi molecules and the −CH 3 and −CH 2 − groups in stearic acid. 32 The high-resolution XPS spectrum of the N 1s region of MF is deconvoluted into three peaks, centered at 398 eV (N−), 399.4 eV (−NH − ), and 400.4 eV (−N + −). As compared to the MF, a new N 1s peak at 402.25 eV could be observed over TiO 2 -PANi@MF, which is mainly because of the protonated imine species (N + ) caused by the surface OH groups of TiO 2 with an interchain H-bonding.…”

“…Figure c shows that both the MF substrate and TiO 2 -PANi@MF exhibit only the C 1s, O 1s, and N 1s features. The enhancement of the C 1s peak is due to the presence of the C–C, CC, CN, and C–N groups in PANi molecules and the −CH 3 and −CH 2 – groups in stearic acid . The high-resolution XPS spectrum of the N 1s region of MF is deconvoluted into three peaks, centered at 398 eV (N−), 399.4 eV (−NH – ), and 400.4 eV (−N + −).…”

“…Diatoms are the most successful planktonic photosynthetic organisms in nature for light energy utilization. 32 The hierarchical structures of diatoms consist of a chitin porous skeleton network covered by an inner layer of a biosilicaassociated protein and an outer biosilica layer. The porous skeleton network and unique nano-aperture architectures of silica endow diatoms with inherently superior light-harvesting capability.…”

“…Diatoms are the most successful planktonic photosynthetic organisms in nature for light energy utilization . The hierarchical structures of diatoms consist of a chitin porous skeleton network covered by an inner layer of a biosilica-associated protein and an outer biosilica layer.…”

Synthetic biology as driver for the biologization of materials sciences

“… Protein class Description Reference Silicatein A bioorganic–inorganic hybrid material is produced by the incorporation of nanoparticles into sponge spicules [ 73 ] Bacterial biofilm protein (CsgA), silaffin A diatom frustule-like structure is built by harnessing a curli biofilm protein, a chitin-binding domain, and a silaffin peptide, which together serve as a scaffold for silica mineralization. The construction of an artificial photosynthesis system is achieved upon colonization of the material with living cells [ 74 ] Silaffin Recombinant silaffin peptides from diatoms, which nucleate the formation of silica nanostructures, are produced in E. coli with different post-translational modifications, obtaining nanostructures with different properties [ 75 ] A genetically engineered diatom produces silaffin peptides fused to proteins of interest, resulting in the immobilization of the protein in the diatom silica [ 75 ] A genetically engineered diatom produces a silica matrix displaying antibodies on its surface. This material is applied for the targeted delivery of chemotherapeutic drugs [ 76 ] A genetically engineered diatom produces a silica matrix that incorporates proteins of interest.…”