TY - JOUR AB - Molecular catch bonds are ubiquitous in biology and essential for processes like leucocyte extravasion1 and cellular mechanosensing2. Unlike normal (slip) bonds, catch bonds strengthen under tension. The current paradigm is that this feature provides ‘strength on demand3’, thus enabling cells to increase rigidity under stress1,4,5,6. However, catch bonds are often weaker than slip bonds because they have cryptic binding sites that are usually buried7,8. Here we show that catch bonds render reconstituted cytoskeletal actin networks stronger than slip bonds, even though the individual bonds are weaker. Simulations show that slip bonds remain trapped in stress-free areas, whereas weak binding allows catch bonds to mitigate crack initiation by moving to high-tension areas. This ‘dissociation on demand’ explains how cells combine mechanical strength with the adaptability required for shape change, and is relevant to diseases where catch bonding is compromised7,9, including focal segmental glomerulosclerosis10 caused by the α-actinin-4 mutant studied here. We surmise that catch bonds are the key to create life-like materials. AU - Mulla, Yuval AU - Avellaneda Sarrió, Mario AU - Roland, Antoine AU - Baldauf, Lucia AU - Jung, Wonyeong AU - Kim, Taeyoon AU - Tans, Sander J. AU - Koenderink, Gijsje H. ID - 12085 IS - 9 JF - Nature Materials SN - 1476-1122 TI - Weak catch bonds make strong networks VL - 21 ER - TY - JOUR AB - Spin qubits are considered to be among the most promising candidates for building a quantum processor. Group IV hole spin qubits have moved into the focus of interest due to the ease of operation and compatibility with Si technology. In addition, Ge offers the option for monolithic superconductor-semiconductor integration. Here we demonstrate a hole spin qubit operating at fields below 10 mT, the critical field of Al, by exploiting the large out-of-plane hole g-factors in planar Ge and by encoding the qubit into the singlet-triplet states of a double quantum dot. We observe electrically controlled X and Z-rotations with tunable frequencies exceeding 100 MHz and dephasing times of 1μs which we extend beyond 15μs with echo techniques. These results show that Ge hole singlet triplet qubits outperform their electronic Si and GaAs based counterparts in speed and coherence, respectively. In addition, they are on par with Ge single spin qubits, but can be operated at much lower fields underlining their potential for on chip integration with superconducting technologies. AU - Jirovec, Daniel AU - Hofmann, Andrea C AU - Ballabio, Andrea AU - Mutter, Philipp M. AU - Tavani, Giulio AU - Botifoll, Marc AU - Crippa, Alessandro AU - Kukucka, Josip AU - Sagi, Oliver AU - Martins, Frederico AU - Saez Mollejo, Jaime AU - Prieto Gonzalez, Ivan AU - Borovkov, Maksim AU - Arbiol, Jordi AU - Chrastina, Daniel AU - Isella, Giovanni AU - Katsaros, Georgios ID - 8909 IS - 8 JF - Nature Materials SN - 1476-1122 TI - A singlet triplet hole spin qubit in planar Ge VL - 20 ER - TY - JOUR AB - Potassium–air batteries, which suffer from oxygen cathode and potassium metal anode degradation, can be cycled thousands of times when an organic anode replaces the metal. AU - Petit, Yann K. AU - Freunberger, Stefan Alexander ID - 7283 IS - 4 JF - Nature Materials SN - 1476-1122 TI - Thousands of cycles VL - 18 ER - TY - JOUR AB - Establishing precise control over the shape and the interactions of the microscopic building blocks is essential for design of macroscopic soft materials with novel structural, optical and mechanical properties. Here, we demonstrate robust assembly of DNA origami filaments into cholesteric liquid crystals, one-dimensional supramolecular twisted ribbons and two-dimensional colloidal membranes. The exquisite control afforded by the DNA origami technology establishes a quantitative relationship between the microscopic filament structure and the macroscopic cholesteric pitch. Furthermore, it also enables robust assembly of one-dimensional twisted ribbons, which behave as effective supramolecular polymers whose structure and elastic properties can be precisely tuned by controlling the geometry of the elemental building blocks. Our results demonstrate the potential synergy between DNA origami technology and colloidal science, in which the former allows for rapid and robust synthesis of complex particles, and the latter can be used to assemble such particles into bulk materials. AU - Siavashpouri, M AU - Wachauf, CH AU - Zakhary, MJ AU - Praetorius, Florian M AU - Dietz, H AU - Dogic, Z ID - 14309 IS - 8 JF - Nature Materials SN - 1476-1122 TI - Molecular engineering of chiral colloidal liquid crystals using DNA origami VL - 16 ER - TY - JOUR AB - Kinetics of electrochemical reactions are several orders of magnitude slower in solids than in liquids as a result of the much lower ion diffusivity. Yet, the solid state maximizes the density of redox species, which is at least two orders of magnitude lower in liquids because of solubility limitations. With regard to electrochemical energy storage devices, this leads to high-energy batteries with limited power and high-power supercapacitors with a well-known energy deficiency. For such devices the ideal system should endow the liquid state with a density of redox species close to the solid state. Here we report an approach based on biredox ionic liquids to achieve bulk-like redox density at liquid-like fast kinetics. The cation and anion of these biredox ionic liquids bear moieties that undergo very fast reversible redox reactions. As a first demonstration of their potential for high-capacity/high-rate charge storage, we used them in redox supercapacitors. These ionic liquids are able to decouple charge storage from an ion-accessible electrode surface, by storing significant charge in the pores of the electrodes, to minimize self-discharge and leakage current as a result of retaining the redox species in the pores, and to raise working voltage due to their wide electrochemical window. AU - Mourad, Eléonore AU - Coustan, Laura AU - Lannelongue, Pierre AU - Zigah, Dodzi AU - Mehdi, Ahmad AU - Vioux, André AU - Freunberger, Stefan Alexander AU - Favier, Frédéric AU - Fontaine, Olivier ID - 7279 IS - 4 JF - Nature Materials SN - 1476-1122 TI - Biredox ionic liquids with solid-like redox density in the liquid state for high-energy supercapacitors VL - 16 ER - TY - JOUR AB - Rechargeable lithium–air (O2) batteries are receiving intense interest because their high theoretical specific energy exceeds that of lithium-ion batteries. If the Li–O2 battery is ever to succeed, highly reversible formation/decomposition of Li2O2 must take place at the cathode on cycling. However, carbon, used ubiquitously as the basis of the cathode, decomposes during Li2O2 oxidation on charge and actively promotes electrolyte decomposition on cycling. Replacing carbon with a nanoporous gold cathode, when in contact with a dimethyl sulphoxide-based electrolyte, does seem to demonstrate better stability. However, nanoporous gold is not a suitable cathode; its high mass destroys the key advantage of Li–O2 over Li ion (specific energy), it is too expensive and too difficult to fabricate. Identifying a suitable cathode material for the Li–O2 cell is one of the greatest challenges at present. Here we show that a TiC-based cathode reduces greatly side reactions (arising from the electrolyte and electrode degradation) compared with carbon and exhibits better reversible formation/decomposition of Li2O2 even than nanoporous gold (>98% capacity retention after 100 cycles, compared with 95% for nanoporous gold); it is also four times lighter, of lower cost and easier to fabricate. The stability may originate from the presence of TiO2 (along with some TiOC) on the surface of TiC. In contrast to carbon or nanoporous gold, TiC seems to represent a more viable, stable, cathode for aprotic Li–O2 cells. AU - Ottakam Thotiyl, Muhammed M. AU - Freunberger, Stefan Alexander AU - Peng, Zhangquan AU - Chen, Yuhui AU - Liu, Zheng AU - Bruce, Peter G. ID - 7306 IS - 11 JF - Nature Materials SN - 1476-1122 TI - A stable cathode for the aprotic Li–O2 battery VL - 12 ER - TY - JOUR AB - Li-ion batteries have transformed portable electronics and will play a key role in the electrification of transport. However, the highest energy storage possible for Li-ion batteries is insufficient for the long-term needs of society, for example, extended-range electric vehicles. To go beyond the horizon of Li-ion batteries is a formidable challenge; there are few options. Here we consider two: Li–air (O2) and Li–S. The energy that can be stored in Li–air (based on aqueous or non-aqueous electrolytes) and Li–S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed. Fundamental scientific advances in understanding the reactions occurring in the cells as well as new materials are key to overcoming these obstacles. The potential benefits of Li–air and Li–S justify the continued research effort that will be needed. AU - Bruce, Peter G. AU - Freunberger, Stefan Alexander AU - Hardwick, Laurence J. AU - Tarascon, Jean-Marie ID - 7313 IS - 1 JF - Nature Materials SN - 1476-1122 TI - Li–O2 and Li–S batteries with high energy storage VL - 11 ER - TY - JOUR AB - Micropatterning of surfaces with several chemicals at different spatial locations usually requires multiple stamping and registration steps. Here, we describe an experimental method based on reaction–diffusion phenomena that allows for simultaneous micropatterning of a substrate with several coloured chemicals. In this method, called wet stamping (WETS), aqueous solutions of two or more inorganic salts are delivered onto a film of dry, ionically doped gelatin from an agarose stamp patterned in bas relief. Once in conformal contact, these salts diffuse into the gelatin, where they react to give deeply coloured precipitates. Separation of colours in the plane of the surface is the consequence of the differences in the diffusion coefficients, the solubility products, and the amounts of different salts delivered from the stamp, and is faithfully reproduced by a theoretical model based on a system of reaction–diffusion partial differential equations. The multicolour micropatterns are useful as non-binary optical elements, and could potentially form the basis of new applications in microseparations and in controlled delivery. AU - Klajn, Rafal AU - Fialkowski, Marcin AU - Bensemann, Igor T. AU - Bitner, Agnieszka AU - Campbell, C. J. AU - Bishop, Kyle AU - Smoukov, Stoyan AU - Grzybowski, Bartosz A. ID - 13435 JF - Nature Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry SN - 1476-1122 TI - Multicolour micropatterning of thin films of dry gels VL - 3 ER -