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Hybrids of biomacromolecules and modern two- dimensional materials

Compared to bulk material, interfaces exhibit additional rich physical phenomena. Functionalized surfaces represent interfaces which are of great importance not only in fundamental surface and materials science but also for applications, which is additionally emphasized by the fact that most of the microelectronic devices used today are based on planar designs. One implementation of functionalized surfaces are hybrid materials. These bridge the gap between living matter and technology and may consist of a solid state substrate and a layer of biomacromolecules. This work is focused on two-dimensional (2D) materials studied as substrates for the growth of a biomacromolecular layer, leading to hybrid structures. In the studied hybrid systems both components have similar symmetry or distribution on a lateral scale, leading to a possible template effect of the substrate: hexagonal symmetry of the nanotemplated 2D material in combination with the DNA origami tetrahedral structure. Two different 2D material templates were investigated: either functionalized graphene or molybdenum disulphide, both on Ir(111) crystalline support. Graphene was grown directly on Ir(111) and subsequently functionalized with AuIr nanoclusters self-assembled on a graphene moiré pattern into a hexagonal array. MoS2 was grown on SiO2 substrate and then transferred to Ir(111). Both 2D substrates were extensively characterized down to the nanoscale, and their stability under ambient and in liquid conditions was confirmed. Taking into account the chemical specificity of the template materials (e.g. gold nanoclusters on graphene or sulphur vacancies in MoS2), tetrahedron shaped DNA origami constructs with thiol groups in three of the vertexes were chosen as biomacromolecules of interest. Tetrahedra adsorption was calibrated on flat gold surfaces, and then applied to both 2D supports, thus producing two different hybrid systems, which were subsequently characterized. Such hybrid systems and their measured properties give promise for future applications in bio- optoelectronics as building blocks in e.g. sensor chips or DNA microarrays.

2D materials ; graphene ; MoS2 monolayer ; nanocluster array ; atomic defects ; DNA-based constructs ; nano-bio hybrid materials ; bio-optoelectronics

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