2D Materials Nanoarchitectonics for 3D Structures/Functions

Abstract

It has become clear that superior material functions are derived from precisely controlled nanostructures. This has been greatly accelerated by the development of nanotechnology. The next step is to assemble materials with knowledge of their nano-level structures. This task is assigned to the post-nanotechnology concept of nanoarchitectonics. However, nanoarchitectonics, which creates intricate three-dimensional functional structures, is not always easy. Two-dimensional nanoarchitectonics based on reactions and arrangements at the surface may be an easier target to tackle. A better methodology would be to define a two-dimensional structure and then develop it into a three-dimensional structure and function. According to these backgrounds, this review paper is organized as follows. The introduction is followed by a summary of the three issues; (i) 2D to 3D dynamic structure control: liquid crystal commanded by the surface, (ii) 2D to 3D rational construction: a metal-organic framework (MOF) and a covalent organic framework (COF); (iii) 2D to 3D functional amplification: cells regulated by the surface. In addition, this review summarizes the important aspects of the ultimate three-dimensional nanoarchitectonics as a perspective. The goal of this paper is to establish an integrated concept of functional material creation by reconsidering various reported cases from the viewpoint of nanoarchitectonics, where nanoarchitectonics can be regarded as a method for everything in materials science.

Keywords: covalent organic framework (COF); liquid crystal; living cell; metal–organic framework (MOF); nanoarchitectonics; surface; three dimensions; two dimensions.

Figure 1

Outline of the nanoarchitectonics concept which establishes a methodology for building functional material systems from nano-units such as atoms, molecules, and nanomaterials.

Figure 2

Three topics presented in this review article: (i) 2D to 3D dynamic structure control: liquid crystal commanded by the surface; (ii) 2D to 3D rational construction: MOF and COF; (iii) 2D to 3D functional amplification: cells regulated by the surface.

Figure 3

Evaluation of the optical orientation behavior of side-chain liquid crystalline azobenzene polymer films with a thickness of approximately 400 nm and a 35 μm thick low-molecular-weight nematic liquid crystal, 4′-pentyl-4-cyanobiphenyl in situ at the interface. Reprinted with permission from [267]. Copyright 2023 American Chemical Society.

Figure 4

Nematic-to-isotropic transition of liquid crystalline components doped with a photochromic azobenzene surfactant in core–sheath nanofibers. Reprinted with permission from [268]. Copyright 2021 Royal Society of Chemistry.

Figure 5

A method to rationally design and synthesize crosslinked COFs in which the two-dimensional COF layers are covalently fixed and linked by poly(ethylene glycol) (PEG) three-dimensional or alkyl chains. Reprinted with permission from [285]. Copyright 2023 American Chemical Society.

Figure 6

Nanoarchitectonics of three-dimensional COFs based on a two-dimensional network with interpenetrations where the structures were formed by [3+2]imine condensation reactions using triangular knots and linear linkers. Reprinted with permission from [286]. Copyright 2023 American Chemical Society.

Figure 7

A method to form three-dimensional COFs by introducing steric hindrance to molecular blocks that inhibit π–π stacking, as a method for two-dimensional COFs to intertwine with each other. Reprinted with permission from [287]. Copyright 2023 American Chemical Society.

Figure 8

Pseudo-three-dimensional COF nanosheets for detection of biomolecules, including COVID-19 virus where the pseudo-three-dimensional COF nanosheet functions as an adsorbent for biomolecular probes and an acceptor to quench the fluorescence of dye-labeled probes. Reprinted with permission from [288]. Copyright 2023 Royal Society of Chemistry.

Figure 9

A cobalt MOF based on a well-defined layered double core strongly bound by intermolecular bonds in which its three-dimensional structure is maintained by π–π stacking interactions between the unstable pyridine ligands of the nanosheets. Reprinted with permission from [289]. Copyright 2020 American Chemical Society.

Figure 10

Organometallic frameworks with orthogonal nanosheet arrays for cubic MOFs. Reproduced under terms of the CC-BY license [290]. Copyright 2023 Springer-Nature.

Figure 11

A strategy to grow MOFs into nanochannels with angstrom-scale ion channels with one- to three-dimensional pore structures. Reproduced under terms of the CC-BY license [291]. Copyright 2023 Springer-Nature.

Figure 12

A method for converting two-dimensionally conjugated MOFs into a three-dimensional framework by post-synthetic pillar ligand insertion. Reprinted with permission from [292]. Copyright 2022 American Chemical Society.

Figure 13

Preparation of a new hierarchical MOF with Cu(II) centers linked by benzene tricarbox-ylates. Reprinted with permission from [293]. Copyright 2017 American Chemical Society.

Figure 14

Synthesis of a two-dimension-on-three-dimension (2D-on-3D) hetero-MOF structure. Reprinted with permission from [294]. Copyright 2022 Wiley VCH.

Figure 15

Synthesis of a series of hafnium (Hf)-based two-dimensional metal–organic layers with different thicknesses (from single layer to stacked multilayers) and densities of hydrogen-bonding sites with inhibition capability of ice growth. Reprinted with permission from [295]. Copyright 2023 Wiley VCH.

Figure 16

A technique that uses the interface between two immiscible liquids, aqueous cell culture solutions and perfluorocarbons, as a site for culturing and inducing differentiation of human mesenchymal stem cells (hMSCs). Reprinted with permission from [296]. Copyright 2019 Wiley VCH.

Figure 17

Culture on a two-dimensional network of protein nanofibrils at the liquid–liquid interface for neural differentiation of hMSCs where lipid raft microdomains were found to play a central regulatory role in both the initial cell adhesion and subsequent neural differentiation of hMSCs. Reproduced under terms of the CC-BY license [297]. Copyright 2022 Springer-Nature.

Figure 18

Interfacial dynamics of bovine serum albumin (BSA) and β-lactoglobulin (BLG) aggregates at the fluorinated liquid-water interface where high cell proliferation can be achieved even on bioemulsions with protein nanosheet formation without surfactants. Reproduced under terms of the CC-BY license [298]. Copyright 2023 American Chemical Society.

Figure 19

Cell spreading and growth on low-viscous liquid surfaces enabled by the self-assembly of mechanically strong protein nanosheets at the interface. Reproduced under terms of the CC-BY license [299]. Copyright 2018 American Chemical Society.

Figure 20

Muscle differentiation and simultaneously controlling the direction of cell growth on the two-dimensional in-plane aligned structure of fullerene nanowhiskers as a cell scaffold. Reprinted with permission from [310]. Copyright 2015 Wiley VCH.

Figure 21

Nanopatterned surfaces fabricated with high-aspect-ratio fullerene nanowhiskers for long-term pluripotency retention and differentiation potential of hMSCs where mechanical signals are transmitted to the nucleus by YAP and YAP translocation to the nucleus positively regulates the activity of core regulators (OCT4, SOX2, NANOG). Reproduced under terms of the CC-BY license [311]. Copyright 2020 American Chemical Society.