Porous organic cages: modular, soluble and molecular pores
Ming Liu1,2
1

Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China

2ZJU-Hangzhou Global Scientific and Technological Innovation Canter, Hangzhou, Zhejiang 311215, China
mingliu@zju.edu.cn
Keywords: porous organic cages, molecular crystals, pollutants capture

Porous molecular cages are an alternative to porous extended frameworks such as zeolites, metal-organic frameworks (MOFs),
covalent organic frameworks (COFs), and microporous polymer networks. One distinguishing property of molecular materials istheir solubility: unlike extended frameworks, molecular crystals can be processed in solution into a variety of formats, or even as“porous liquid”. They can also show unique physical properties, such as perfect shape selectivity for rare gases or organic isomers
and protonic conductivity. However, molecular crystals also raise challenges in terms of stability and the purposeful design of solidstate function [1]. This is because the energy landscape for molecular crystals is often not dominated by a single intermolecularinteraction, unlike bonded crystalline frameworks such as MOFs and covalent organic frameworks. This talk will discuss strategies
for the design and synthesis of new functional organic crystals by using a mixture of intuitive design and computation. The talk will
exemplify this with recent examples of post-synthetic modification of porous organic cages, in which their stability or function canbe tuned [2]. Some most recent progress of using cages in real-life applications, such as for pollutants capture, will also be introduced[3].
Reference:[1] Slater, A. G.; Cooper, A. I. Science, 2015, 348, 988.
[2] Liu, M.; Zhang, L.; Little, M. A.; Kapil, V.; Ceriotti, M.; Yang, S.; Ding, L.; Holden, D. L.; Balderas-Xicohténcatl, R.; He, D.;
Clowes, Rob.; Chong, S. Y.; Schütz, G.; Chen, L.; Hirscher, M.; Cooper, A. I. Science, 2019, 366, 613.
[3] Martínez-Ahumada, E.; He, D.; Berryman, V.; López-Olvera, A.; Hernandez, M.; Jancik, V.; Martis, V.; Vera, M. A.; Lima, E.;
Parker, D. J.; Cooper, A. I. *; Ibarra, I. A.; Liu, M. Angew. Chem. Int. Ed., 2021, 60, 17556.

De novo design of nanopores reconstituted in bilayer lipid membraneRyuji Kawano
Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology (TUAT)
2-24-16 Nakacho Koganei, Tokyo 184-8588 Japan
Email: rjkawano@cc.tuat.ac.jp
Keywords: Nanopores, Lipid bilayers, Peptides, De novo design
Nanopore sensing/sequencing are emerging technologies for rapid and low-cost single-molecule detection. Pore-forming proteins
are used as the sensor component and their size and geometry compatibility for the target molecule are essential for detectability. A
bottom-up approach, de novo design of the amino acids sequence, is a potent tool for constructing target-specific nanopores. We
have recently reported de novo peptide nanopores and they have several advantages such as low-cost synthesis, chemical stability,
and the ability to readily reconstitute in a lipid membrane.
The pore-forming peptide, named SV28, that has a β-hairpin structure and assembles to form a stable nanopore in a bilayer
lipid membrane. The peptide forms multidispersely sized nanopore structures ranging from 1.7 to 6.3 nm in diameter and can detect
DNAs. To form a monodispersely sized nanopore, we redesigned the SV28 by introducing a glycine-kink mutation. The resulting
redesigned peptide forms a monodisperse pore with a diameter of 1.7 nm leading to detection of a single polypeptide chain.[1] In
this seminar, I will give the detailed results on a construction of de novo designed nanopore with a lipid bilayer system based on a
microfabrication technology.

Figure 1. MD simulation of the de novo designed peptides that form a nanopore structure in lipid bilayer.
[1] Shimizu, K., Mijiddorj, B., Usami, M. et al. De novo design of a nanopore for single-molecule detection that incorporates a βhairpin peptide. Nat. Nanotechnol. 17, 67–75 (2022). https://doi.org/10.1038/s41565-021-01008-w

Biological pores found in membrane proteins
Hideaki Kato1,2
Komaba Institute for Science, The University of Tokyo
hekato@bio.c.u-tokyo.ac.jp
Keywords: ion pumps, ion channels, rhodopsins

The cell is the basic unit of life, and the plasma membrane defines its boundaries and maintains the differences between theintracellular and the extracellular environment. The plasma membrane is impermeable to water-soluble molecules, including ionsand most biological molecules, so these molecules enter or leave cells mainly via membrane transporters (pumps) or channels.
Pumps and channels specifically recognize their substrates and regulate the timing and direction of the substrate transport bydynamically changing the shape and property of “pores”. In this talk, first I will introduce the basic concept and classic examples
of membrane pumps and channels and later focus on the specific family of membrane proteins called rhodopsins. Rhodopsins are alarge family of photoreceptive membrane proteins found in archaea, bacteria, eukaryotes, and viruses. They are seven-helix
transmembrane proteins that are covalently bound to a retinal chromophore, and their diverse molecular functions include ion pumps
and ion channels. I will talk about the structural foundation of these pump-type and channel-type rhodopsins and discuss how
biological pores with different shapes and properties can exert diverse molecular functions.

Figure 1. Biological pores with different molecular functions in rhodopsin family proteinsShape-shifting porous crystals
Hiroshi SatoRiken Center for Emergent Matter Science, JST-PRESTO
hiroshi.sato@riken.jp
Keywords: Porous materials, Crystals, Stimuli-response
Porous materials with nanometer-sized pores have long been used in our daily lives as functional materials that efficiently separate
and remove small molecules such as gaseous molecules. As a new family of porous materials, metal–organic frameworks (MOFs)
are synthesized by combining metal ions and organic ligands, and the size, shape, and chemical properties of their pores can be
designed and tuned by taking advantage of the combination diversity of the constituents. Compared to conventional porous materials,MOFs are unique in that they can flexibly change their structures in response to the environment, despite their crystalline nature[1–4]. We are studying the synthesis and unprecedented function of such unique porous materials in which "hardness" and "softness"
operate in concert. In this presentation, I would like to introduce MOF-based porous crystals that respond to external stimuli (Figure1) with shape-shifting properties. Especially, I will present crystals that respond to guest molecules[5–7], light[8–12], and mechanicalforces[13].

Figure 1. Stimuli-responsive porous crystals.
References[1] S. Horike, S. Shimomura, S. Kitagawa, Nat. Chem. 2009, 1, 695. [2] A. Schneemann, V. Bon, I. Schwedler, I. Senkovska, S. Kaskel, R. A.
Fischer, Chem. Soc. Rev. 2014, 43, 6062. [3] Z. Chang, D.‐H. Yang, J. Xu, T.‐L. Hu, X.‐H. Bu, Adv. Mater. 2015, 27, 5432. [4] S. K. Elsaidi, M.
H. Mohamed, D. Banerjee, P. K. Thallapally, Coord. Chem. Rev. 2018, 358, 125. [5] H. Sato et al. Science 2014, 343, 167. [6] V. K.-M. Au et al.
J. Am. Chem. Soc. 2019, 141, 53. [7] S. Suginome et al. J. Am. Chem. Soc. 2019, 141, 15649. [8] H. Sato et al. Chem. Commun. 2012, 48, 7911.
[9] H. Sato et al. Nature Mater. 2010, 9, 661. [10] H. Huang et al. J. Am. Chem. Soc. 2017, 139, 8784. [11] Y. Zheng et al. Nature Commun. 2017,8, 100. [12] H. Sato et al., J. Am. Chem. Soc. 2020, 142, 14069. [13] W. Meng et al. Nature 2021, 598, 298.

Hydrogen Separation Membrane Technology for Net-Zero Carbon Dioxide Economy
水素分離膜技術で CO2 ネットゼロ経済を○Easan Sivaniah 1,2 , Behnam Ghalei 1,2( 1 iCeMS, Kyoto University, 2 Dept. of Molecular Engineering, Kyoto University)
1Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto Univ., 606-8501 Kyoto, Japan.
2

Dept. of Molecular Engineering, Graduate School of Engineering, Kyoto University,
Nishikyo-Ku, 615-8510 Kyoto, Japan.

Opportunity for membrane technology in hydrogen economy
A hydrogen economy has the potential to solve many problems caused by the direct use of fossil
fuels via clean energy and transportation 1 . More than 90% of about 70 million tons worldwide
demand for hydrogen is currently generated via steam reforming and the water‐gas‐shift (WGS)
reaction of fossil fuel sources 2 . This produces an almost 50:50 mixture of hydrogen and carbon
dioxide saturated with steam 3,4 from which hydrogen is subsequently purified by selectively
adsorbing the CO 2 using aminated solvents. Unlike amine adsorption processes, membrane
separation requires no changes in phase behavior and is in principle the most energeticallycost-effective route for primary purification of H 2 and CO 2 4,5 .

Challenge for membrane technology in Hydrogen Economy.
However polymeric membranes do not have adequate separation capability of CO 2 from H 2 due tothe high level of solubility of CO 2 in organic materials 6,7 . Costly metallic membranes 8 and ceramic
membranes 9 , operating on the principles of selective adsorption or molecular sieving haveextraordinary selectivity for hydrogen against carbon dioxide; ~1000 and ~300 respectively andsufficient rates of permeance.

In the early 2010's, ultrathin graphene oxide (GO) was proposed as a step-change material for theseparation of hydrogen and carbon dioxide via membrane separation processes 10,11 . Selectivities of
up to 1000 and triple-digit (~000 GPU) permeances were reported. GO itself is cheaply sourced
through controlled oxidation and exfoliation of graphite. These capabilities are ideal for highly
efficient H 2 separation, to reach purity levels required for immediate use in fuel cells. However,swelling and disruption of the basal stacking of the carbon sheets in humid conditions is theAchilles heel of GO membranes, presenting an un-resolved obstacle to the practicalimplementation of this exciting technology 12,13 .

Electrostatic stabilization of charged 2D materials.
Recently we reported how we specifically target the stabilization of GO membranes towards
adverse humid conditions, whilst attempting to maintain its overall high performance towards
H2/CO2 separation.

To do so, we employed the concept of pillared clays 14 , used in catalysis,

where nearly compatible compounds are intercalated within layered silicates to strengthen theirsecondary structure (Figure). Taking the compatibility of carbonaceous materials into account, we
surmised that robust nanodiamonds (NDs) with unique sp3/sp2 core-shell structure and positive
surface charge are capable of restraining the random restacking and aggregation of GO
nanosheets. 15

Conclusion.
We have demonstrated the benefit of the intentional addition of positively charged carbonaceous
nanoparticles, here exemplified through NDs that serve to stabilize negatively charged GO
membrane sheets against humidity enhanced destabilization of the membrane's separation
performance, whilst enhancing its intrinsic separation performance tremendously. Despite
constraining our study to a single size scale of nanoparticle of different charge, and single size
distribution of GO sheets, a significant data set was generated. However, a larger set ofunanswered questions remain, such as relative size effects, the chemical nature of the particle, andmore broadly, whether such charge stabilization can also be applicable to other novel materials
such as MXenes (also a negatively charged 2D material).

Answering such questions in the future

will serve to generate high stability, 2D material composites, not only for membrane separation
but also for other application areas where the field of 2D materials is gaining purchase.

Conclusion.
1
Sartbaeva, A., Kuznetsov, V., Wells, S. & Edwards, P. Hydrogen nexus in a sustainableenergy future. Energy & Environmental Science 1, 79-85 (2008).
2
Voldsund, M., Jordal, K. & Anantharaman, R. Hydrogen production with CO2 capture.
International Journal of Hydrogen Energy 41, 4969-4992 (2016).
3
Japip, S., Liao, K. S. & Chung, T. S. Molecularly tuned free volume of vapor cross‐linked 6FDA‐Durene/ZIF‐71 MMMs for H2/CO2 separation at 150° C. AdvancedMaterials 29, 1603833 (2017).
4Merkel, T. C., Zhou, M. & Baker, R. W. Carbon dioxide capture with membranes at an
IGCC power plant. Journal of membrane science 389, 441-450 (2012).
5Wassie, S. A. et al. Hydrogen production with integrated CO2 capture in a membrane
assisted gas switching reforming reactor: proof-of-Concept. International Journal ofHydrogen Energy 43, 6177-6190 (2018).
6Zhang, M. et al. Electropolymerization of molecular‐sieving polythiophene
membranes for H2 separation. Angewandte Chemie 131, 8860-8864 (2019).
7Ghalei, B. et al. Rational Tuning of Zirconium Metal‐Organic Framework Membranes
for hydrogen purification. Angewandte Chemie International Edition (2019).
8Ockwig, N. W. & Nenoff, T. M. Membranes for hydrogen separation. Chemical reviews
107, 4078-4110 (2007).
9Yu, M., Funke, H. H., Noble, R. D. & Falconer, J. L. H2 separation using defect-free,inorganic composite membranes. Journal of the American Chemical Society 133, 1748-1750(2011).
10Kim, H. W. et al. Selective gas transport through few-layered graphene and graphene
oxide membranes. Science 342, 91-95 (2013).
11Li, H. et al. Ultrathin, molecular-sieving graphene oxide membranes for selectivehydrogen separation. Science 342, 95-98 (2013).
12Kim, H. W. et al. High-performance CO 2-philic graphene oxide membranes underwet-conditions. Chemical Communications 50, 13563-13566 (2014).
13Abraham, J. et al. Tunable sieving of ions using graphene oxide membranes. Naturenanotechnology 12, 546 (2017).
14Figueras, F. Pillared clays as catalysts. Catalysis Reviews Science and Engineering 30,457-499 (1988).
15Mochalin, V. N., Shenderova, O., Ho, D. & Gogotsi, Y. The properties and applicationsof nanodiamonds. Nature nanotechnology 7, 11 (2012).

Looking Beyond Crystallinity in
Metal-Organic Frameworks

Thomas Douglas Bennett
University of Cambridge
Department of Materials Science and Metallurgy, University of Cambridge, United Kingdom
Tdb35@cam.ac.uk
Keywords: MOFs, Glass, Liquid
Metal-organic framework (MOF) materials are often ordered, (crystalline) solids. Order—or uniformity— is frequently held to beadvantageous, or even pivotal, to our ability to engineer useful properties in a rational way. Here, we will look at the difference
between amorphous, and glassy solids, and cover the mechanisms underpinning the shear-induced collapse of MOFs. Using thecrystalline MIL-100 / amorphous Fe-BTC pairing as an example, we will then address the poorly understood structure of thelatter. Specifically, we show an experimental-computational approach to generate a ‘structure’ for Fe-BTC, and show it may
outperform MIL-100 In terms of gas separation.1
We will demonstrate the several families of MOFs known to form stable liquids at high temperature,2,3 with quenching leading tothe formation of glasses which retain the three-dimensional inorganic-organic bonding of the crystalline phase. The uses of suchmaterials will be evaluated, before we finally show how the formation of composites containing both MOF, and glass phases may
find use in applications. 4,5

1
Sapnik, A. F. et al. Mixed hierarchical local structure in a disordered metal-organic framework. Nat Commun 12, 2062,(2021).
2Shaw, B. K. et al. Melting of hybrid organic-inorganic perovskites. Nat Chem 13, 778–785, doi:10.1038/s41557-02100681-7 (2021).
3Bennett, T. D., Coudert, F. X., James, S. L. & Cooper, A. I. The changing state of porous materials. Nat Mater 20, 11791187, (2021).
4
Hou, J. et al. Liquid-phase sintering of lead halide perovskites and metal-organic framework glasses. Science 374, 621625 (2021).
5
Longley, L. et al. Metal-Organic Framework and Inorganic Glass Composites. Nat Commun 11, 5800 (2020).

Building pores with the power of DNA nanotechnology
Stefan Howorka1
3

Department of Chemistry, Institute for Structural and Molecular Biology, University College London, London, WC1H0AJ,England, UKs.howorka@ucl.ac.uk
Keywords: pores, nanopores, DNA, nanotechnology, membranes, bilayers, sensing, single-molecule analysis, biophysics

Porous structures are relevant in many areas of science, technology, and society. Porous 3D materials are used in chemical catalysis
and storage, while thin, porous films are essential for purification of water, foodstuffs, and medicine. Furthermore, thin membranes
with single pores have delivered portable DNA sequencing and biosensing of single molecules. Conventionally, porous structures
are fabricated with organic, polymeric, or solid-state-materials. By comparison, DNA nanotechnology offers another, powerful routeto create highly defined and simple-to-build nanostructures.
In my talk, I will present nanopores composed of DNA. The pores are rationally designed to self-assemble from a few to hundredsof DNA strands using base pair-specific interactions. The pores mimic natural membrane proteins which span biological lipid bilayer
membranes(1) and have pioneered single-molecule sensing(2) and portable DNA sequencing(3). The DNA pores go beyond the scopeof biology in terms of size and shape(4) or controlled nanomechanical movement(5). The design and assembly of the pores follows
newly established protocols(6) and yields unique nanostructures whose assembly(7), structural dynamics(8),membrane transport(9),andmembrane interactions(10) have been characterised with an array of techniques. The DNA pores can be custom-engineering for
portable sensing of diagnostic proteins using commercial handheld-devices(4). The work on DNA nanopores can inspire the wider
field of bioengineering(11) and materials science, and -given its interdisciplinary nature- leads to unexpected changes in graduateteaching(12) and research management(13).

Figure 1. A single nanopore composed of assembled DNA duplexes (cylinders, blue) inserted into a bilayer membrane (grey).
The square pore has an inner lumen of 10 nm by 10 nm. Cholesterol tags (orange) anchor the hydrophilic structure into thehydrophobic bilayer membrane(4).

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17 708; (5) Nat. Nanotechnol. 2016 11 152; (6) Nat. Protoc. 2021 16 86; (7) Nat. Commun. 2022 13 3610; (8) Nat. Commun.
2017 8 14784; (9) Nat. Commun. 2019 10 1; (10) Nat. Commun. 2018 9 1521; (11) Nat. Rev. Chem. 2018 2 113; Science 2016352 890; (12) Nat. Nanotechnol. 2015 10 992; (13) Nat. Rev. Chem. 2022 6 81;