Browsing by Subject "Living materials"
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Item Open Access Design and applications of self-assembled soft living materials using synthetic biology(Elsevier, 2022-01-01) Özkul, Gökçe; Yavuz, Merve; Hacıosmanoğlu, Nedim; Kırpat, Büşra Merve; Şeker, Urartu Özgür ŞafakIn nature, the cells are unique biofactories of various kinds of macroscale structures. These biofactories are as old as the earth. However, as technology developed and new areas of research fields developed these cellular biofactories became the center of attention. The motive was the question if we can engineer them according to the world’s needs. At that point, approaches and tools of synthetic biology came into the picture. After its development, people started to engineer biofactories and produce materials with new properties. One of those materials is classified as self-assembled soft living materials with their specific features and usage areas. To be more specific, biofilms are examples of self-assembled soft living materials due to their self-sustaining and self-assembling properties. They can be engineered starting from genetic circuits leading to creation of their building blocks and finally formation of complex biofilm systems. With the diversity in their engineering aspects, their application areas also vary. In this chapter, the design of biofilm structures from genetic circuits until the formation of complex biofilm structures and their various applications will be investigated.Item Open Access A living material platform for the biomineralization of biosilica(Elsevier B.V., 2022-12-15) Kırpat Konak, Büşra Merve; Bakar, Mehmet Emin; Ahan, Recep Erdem; Özyürek, Emel Uzunoğlu; Dökmeci, Serap; Şafak Şeker, Urartu ÖzgürNature has a vast array of biomineralization mechanisms. The commonly shared mechanism by many living organisms to form hardened tissues is the nucleation of mineral structures via proteins. Living materials, thanks to synthetic biology, are providing many opportunities to program cells for many functionalities. Here we have demonstrated a living material system for biosilicification. Silaffins are utilized to synthesize silicified cell walls by one of the most abundant organism groups called diatoms. The R5 peptide motif of the silaffins is known for its ability to precipitate silica in ambient conditions. Therefore, various studies have been conducted to implement the silicification activity of R5 in different application areas, such as regenerative medicine and tissue engineering. However, laborious protein purification steps are required prior to silica nanoparticle production in recombinant approaches. In this study, we aimed to engineer an alternative bacterial platform to achieve silicification using released and bacteria-intact forms of R5-attached fluorescent proteins (FP). Hence, we displayed R5-FP hybrids on the cell surface of E. coli via antigen 43 (Ag43) autotransporter system and managed to demonstrate heat-controllable release from the surface. We also showed that the bacteria cells displaying R5-FP can be used in silicification reactions. Lastly, considering the stimulating effect of silica on osteogenic differentiation, we treated human dental pulp stem cells (hDPSCs) with the silica aggregates formed via R5-FP hybrids. Earlier calcium crystal deposition around the hDPSCs was observed. We envision that our platform can serve as a faster and more economical alternative for biosilicification applications, including endodontics. © 2022Item Open Access Synthetic biogenesis of bacterial amyloid nanomaterials with tunable inorganic-organic interfaces and electrical conductivity(American Chemical Society, 2017) Seker U.O.S.; Chen, A. Y.; Citorik, R. J.; Lu, T. K.Amyloids are highly ordered, hierarchal protein nanoassemblies. Functional amyloids in bacterial biofilms, such as Escherichia coli curli fibers, are formed by the polymerization of monomeric proteins secreted into the extracellular space. Curli is synthesized by living cells, is primarily composed of the major curlin subunit CsgA, and forms biological nanofibers with high aspect ratios. Here, we explore the application of curli fibers for nanotechnology by engineering curli to mediate tunable biological interfaces with inorganic materials and to controllably form gold nanoparticles and gold nanowires. Specifically, we used cell-synthesized curli fibers as templates for nucleating and growing gold nanoparticles and showed that nanoparticle size could be modulated as a function of curli fiber gold-binding affinity. Furthermore, we demonstrated that gold nanoparticles can be preseeded onto curli fibers and followed by gold enhancement to form nanowires. Using these two approaches, we created artificial cellular systems that integrate inorganic-organic materials to achieve tunable electrical conductivity. We envision that cell-synthesized amyloid nanofibers will be useful for interfacing abiotic and biotic systems to create living functional materials.