@article{13390, author = {Klajn, Rafal}, issn = {1869-1870}, journal = {Science China Chemistry}, keywords = {General Chemistry}, number = {4}, pages = {420--421}, publisher = {Springer Nature}, title = {{Borrowing titania’s photoinduced electrons for molecular switching}}, doi = {10.1007/s11426-016-5573-4}, volume = {59}, year = {2016}, } @article{13391, abstract = {It is reported that spiropyran—a widely investigated molecular photoswitch—can be stabilized in aqueous environments in the presence of a variety of proteins, including human serum albumin, insulin fibrils, lysozyme, and glucose oxidase. The optical properties of the complexed photoswitch are protein dependent, with human serum albumin providing the spiropyran with emission features previously observed for a photoswitch confined in media of high viscosity. Despite being bound to the protein molecules, spiropyran can undergo a ring-opening reaction upon exposure to UV light. This photoisomerization process can affect the properties of the proteins: here, it is shown that the electrical conduction through human serum albumin to which the spiropyran is bound increases following the ring-opening reaction.}, author = {Amdursky, Nadav and Kundu, Pintu K. and Ahrens, Johannes and Huppert, Dan and Klajn, Rafal}, issn = {2192-6506}, journal = {ChemPlusChem}, keywords = {General Chemistry}, number = {1}, pages = {44--48}, publisher = {Wiley}, title = {{Noncovalent interactions with proteins modify the physicochemical properties of a molecular switch}}, doi = {10.1002/cplu.201500417}, volume = {81}, year = {2016}, } @article{11072, abstract = {Spatiotemporal activation of RhoA and actomyosin contraction underpins cellular adhesion and division. Loss of cell–cell adhesion and chromosomal instability are cardinal events that drive tumour progression. Here, we show that p120-catenin (p120) not only controls cell–cell adhesion, but also acts as a critical regulator of cytokinesis. We find that p120 regulates actomyosin contractility through concomitant binding to RhoA and the centralspindlin component MKLP1, independent of cadherin association. In anaphase, p120 is enriched at the cleavage furrow where it binds MKLP1 to spatially control RhoA GTPase cycling. Binding of p120 to MKLP1 during cytokinesis depends on the N-terminal coiled-coil domain of p120 isoform 1A. Importantly, clinical data show that loss of p120 expression is a common event in breast cancer that strongly correlates with multinucleation and adverse patient survival. In summary, our study identifies p120 loss as a driver event of chromosomal instability in cancer. }, author = {van de Ven, Robert A.H. and de Groot, Jolien S. and Park, Danielle and van Domselaar, Robert and de Jong, Danielle and Szuhai, Karoly and van der Wall, Elsken and Rueda, Oscar M. and Ali, H. Raza and Caldas, Carlos and van Diest, Paul J. and HETZER, Martin W and Sahai, Erik and Derksen, Patrick W.B.}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry}, publisher = {Springer Nature}, title = {{p120-catenin prevents multinucleation through control of MKLP1-dependent RhoA activity during cytokinesis}}, doi = {10.1038/ncomms13874}, volume = {7}, year = {2016}, } @article{10381, abstract = {We study phase behaviour of lipid-bilayer vesicles functionalised by ligand–receptor complexes made of synthetic DNA by introducing a modelling framework and a dedicated experimental platform. In particular, we perform Monte Carlo simulations that combine a coarse grained description of the lipid bilayer with state of art analytical models for multivalent ligand–receptor interactions. Using density of state calculations, we derive the partition function in pairs of vesicles and compute the number of ligand–receptor bonds as a function of temperature. Numerical results are compared to microscopy and fluorimetry experiments on large unilamellar vesicles decorated by DNA linkers carrying complementary overhangs. We find that vesicle aggregation is suppressed when the total number of linkers falls below a threshold value. Within the model proposed here, this is due to the higher configurational costs required to form inter-vesicle bridges as compared to intra-vesicle loops, which are in turn related to membrane deformability. Our findings and our numerical/experimental methodologies are applicable to the rational design of liposomes used as functional materials and drug delivery applications, as well as to study inter-membrane interactions in living systems, such as cell adhesion.}, author = {Bachmann, Stephan Jan and Kotar, Jurij and Parolini, Lucia and Šarić, Anđela and Cicuta, Pietro and Di Michele, Lorenzo and Mognetti, Bortolo Matteo}, issn = {1744-6848}, journal = {Soft Matter}, keywords = {condensed matter physics, general chemistry}, number = {37}, pages = {7804--7817}, publisher = {Royal Society of Chemistry}, title = {{Melting transition in lipid vesicles functionalised by mobile DNA linkers}}, doi = {10.1039/c6sm01515h}, volume = {12}, year = {2016}, } @article{8455, abstract = {Solid-state NMR spectroscopy allows the characterization of the structure, interactions and dynamics of insoluble and/or very large proteins. Sensitivity and resolution are often major challenges for obtaining atomic-resolution information, in particular for very large protein complexes. Here we show that the use of deuterated, specifically CH3-labelled proteins result in significant sensitivity gains compared to previously employed CHD2 labelling, while line widths increase only marginally. We apply this labelling strategy to a 468 kDa-large dodecameric aminopeptidase, TET2, and the 1.6 MDa-large 50S ribosome subunit of Thermus thermophilus.}, author = {Kurauskas, Vilius and Crublet, Elodie and Macek, Pavel and Kerfah, Rime and Gauto, Diego F. and Boisbouvier, Jérôme and Schanda, Paul}, issn = {1359-7345}, journal = {Chemical Communications}, keywords = {Materials Chemistry, Electronic, Optical and Magnetic Materials, General Chemistry, Surfaces, Coatings and Films, Metals and Alloys, Ceramics and Composites, Catalysis}, number = {61}, pages = {9558--9561}, publisher = {Royal Society of Chemistry}, title = {{Sensitive proton-detected solid-state NMR spectroscopy of large proteins with selective CH3labelling: Application to the 50S ribosome subunit}}, doi = {10.1039/c6cc04484k}, volume = {52}, year = {2016}, } @article{9019, abstract = {Targeting protein–protein interactions has long been considered as a very difficult if impossible task, but over the past decade, front lines have moved. The number of successful examples is exponentially growing. This review presents a rapid overview of recent advances in this field considering the strengths and weaknesses of the small molecule approaches and alternative strategies such as the selection or design of artificial antibodies, peptides or peptidomimetics.}, author = {Bakail, May M and Ochsenbein, Francoise}, issn = {1631-0748}, journal = {Comptes Rendus Chimie}, keywords = {General Chemistry, General Chemical Engineering}, number = {1-2}, pages = {19--27}, publisher = {Elsevier}, title = {{Targeting protein–protein interactions, a wide open field for drug design}}, doi = {10.1016/j.crci.2015.12.004}, volume = {19}, year = {2016}, } @article{9052, abstract = {We describe colloidal Janus particles with metallic and dielectric faces that swim vigorously when illuminated by defocused optical tweezers without consuming any chemical fuel. Rather than wandering randomly, these optically-activated colloidal swimmers circulate back and forth through the beam of light, tracing out sinuous rosette patterns. We propose a model for this mode of light-activated transport that accounts for the observed behavior through a combination of self-thermophoresis and optically-induced torque. In the deterministic limit, this model yields trajectories that resemble rosette curves known as hypotrochoids.}, author = {Moyses, Henrique and Palacci, Jérémie A and Sacanna, Stefano and Grier, David G.}, issn = {1744-6848}, journal = {Soft Matter}, keywords = {General Chemistry, Condensed Matter Physics}, number = {30}, pages = {6357--6364}, publisher = {Royal Society of Chemistry }, title = {{Trochoidal trajectories of self-propelled Janus particles in a diverging laser beam}}, doi = {10.1039/c6sm01163b}, volume = {12}, year = {2016}, } @article{13393, abstract = {Precise control of the self-assembly of selected components within complex mixtures is a challenging goal whose realization is important for fabricating novel nanomaterials. Herein we show that by decorating the surfaces of metallic nanoparticles with differently substituted azobenzenes, it is possible to modulate the wavelength of light at which the self-assembly of these nanoparticles is induced. Exposing a mixture of two types of nanoparticles, each functionalized with a different azobenzene, to UV or blue light induces the selective self-assembly of only one type of nanoparticles. Irradiation with the other wavelength triggers the disassembly of the aggregates, and the simultaneous self-assembly of nanoparticles of the other type. By placing both types of azobenzenes on the same nanoparticles, we created unique materials (“frustrated” nanoparticles) whose self-assembly is induced irrespective of the wavelength of the incident light.}, author = {Manna, Debasish and Udayabhaskararao, Thumu and Zhao, Hui and Klajn, Rafal}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, keywords = {General Chemistry, Catalysis}, number = {42}, pages = {12394--12397}, publisher = {Wiley}, title = {{Orthogonal light-induced self-assembly of nanoparticles using differently substituted azobenzenes}}, doi = {10.1002/anie.201502419}, volume = {54}, year = {2015}, } @article{13394, abstract = {The ability to guide the assembly of nanosized objects reversibly with external stimuli, in particular light, is of fundamental importance, and it contributes to the development of applications as diverse as nanofabrication and controlled drug delivery. However, all the systems described to date are based on nanoparticles (NPs) that are inherently photoresponsive, which makes their preparation cumbersome and can markedly hamper their performance. Here we describe a conceptually new methodology to assemble NPs reversibly using light that does not require the particles to be functionalized with light-responsive ligands. Our strategy is based on the use of a photoswitchable medium that responds to light in such a way that it modulates the interparticle interactions. NP assembly proceeds quantitatively and without apparent fatigue, both in solution and in gels. Exposing the gels to light in a spatially controlled manner allowed us to draw images that spontaneously disappeared after a specific period of time.}, author = {Kundu, Pintu K. and Samanta, Dipak and Leizrowice, Ron and Margulis, Baruch and Zhao, Hui and Börner, Martin and Udayabhaskararao, T. and Manna, Debasish and Klajn, Rafal}, issn = {1755-4349}, journal = {Nature Chemistry}, keywords = {General Chemical Engineering, General Chemistry}, pages = {646--652}, publisher = {Springer Nature}, title = {{Light-controlled self-assembly of non-photoresponsive nanoparticles}}, doi = {10.1038/nchem.2303}, volume = {7}, year = {2015}, } @article{13395, abstract = {Metallic nanoparticles co-functionalised with monolayers of UV- and CO2-sensitive ligands were prepared and shown to respond to these two types of stimuli reversibly and in an orthogonal fashion. The composition of the coating could be tailored to yield nanoparticles capable of aggregating exclusively when both UV and CO2 were applied at the same time, analogously to the behaviour of an AND logic gate.}, author = {Lee, Ji-Woong and Klajn, Rafal}, issn = {1364-548X}, journal = {Chemical Communications}, keywords = {Materials Chemistry, Metals and Alloys, Surfaces, Coatings and Films, General Chemistry, Ceramics and Composites, Electronic, Optical and Magnetic Materials, Catalysis}, number = {11}, pages = {2036--2039}, publisher = {Royal Society of Chemistry}, title = {{Dual-responsive nanoparticles that aggregate under the simultaneous action of light and CO2}}, doi = {10.1039/c4cc08541h}, volume = {51}, year = {2015}, } @article{14016, abstract = {All attosecond time-resolved measurements have so far relied on the use of intense near-infrared laser pulses. In particular, attosecond streaking, laser-induced electron diffraction and high-harmonic generation all make use of non-perturbative light–matter interactions. Remarkably, the effect of the strong laser field on the studied sample has often been neglected in previous studies. Here we use high-harmonic spectroscopy to measure laser-induced modifications of the electronic structure of molecules. We study high-harmonic spectra of spatially oriented CH3F and CH3Br as generic examples of polar polyatomic molecules. We accurately measure intensity ratios of even and odd-harmonic orders, and of the emission from aligned and unaligned molecules. We show that these robust observables reveal a substantial modification of the molecular electronic structure by the external laser field. Our insights offer new challenges and opportunities for a range of emerging strong-field attosecond spectroscopies.}, author = {Kraus, P. M. and Tolstikhin, O. I. and Baykusheva, Denitsa Rangelova and Rupenyan, A. and Schneider, J. and Bisgaard, C. Z. and Morishita, T. and Jensen, F. and Madsen, L. B. and Wörner, H. J.}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}, publisher = {Springer Nature}, title = {{Observation of laser-induced electronic structure in oriented polyatomic molecules}}, doi = {10.1038/ncomms8039}, volume = {6}, year = {2015}, } @article{8456, abstract = {The large majority of three-dimensional structures of biological macromolecules have been determined by X-ray diffraction of crystalline samples. High-resolution structure determination crucially depends on the homogeneity of the protein crystal. Overall ‘rocking’ motion of molecules in the crystal is expected to influence diffraction quality, and such motion may therefore affect the process of solving crystal structures. Yet, so far overall molecular motion has not directly been observed in protein crystals, and the timescale of such dynamics remains unclear. Here we use solid-state NMR, X-ray diffraction methods and μs-long molecular dynamics simulations to directly characterize the rigid-body motion of a protein in different crystal forms. For ubiquitin crystals investigated in this study we determine the range of possible correlation times of rocking motion, 0.1–100 μs. The amplitude of rocking varies from one crystal form to another and is correlated with the resolution obtainable in X-ray diffraction experiments.}, author = {Ma, Peixiang and Xue, Yi and Coquelle, Nicolas and Haller, Jens D. and Yuwen, Tairan and Ayala, Isabel and Mikhailovskii, Oleg and Willbold, Dieter and Colletier, Jacques-Philippe and Skrynnikov, Nikolai R. and Schanda, Paul}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {General Biochemistry, Genetics and Molecular Biology, General Physics and Astronomy, General Chemistry}, publisher = {Springer Nature}, title = {{Observing the overall rocking motion of a protein in a crystal}}, doi = {10.1038/ncomms9361}, volume = {6}, year = {2015}, } @article{13401, abstract = {A compound combining the features of a molecular rotor and a photoswitch was synthesized and was shown to exist as three diastereomers, which interconvert via a reversible cyclic reaction scheme. Each of the three diastereomers was isolated, and by following the equilibration kinetics, activation barriers for all reactions were calculated. The results indicate that the properties of molecular switches depend heavily on their immediate chemical environment. The conclusions are important in the context of designing new switchable molecules and materials.}, author = {Kundu, Pintu K. and Lerner, Avishai and Kučanda, Kristina and Leitus, Gregory and Klajn, Rafal}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, keywords = {Colloid and Surface Chemistry, Biochemistry, General Chemistry, Catalysis}, number = {32}, pages = {11276--11279}, publisher = {American Chemical Society}, title = {{Cyclic kinetics during thermal equilibration of an axially chiral bis-spiropyran}}, doi = {10.1021/ja505948q}, volume = {136}, year = {2014}, } @article{13402, abstract = {Nanoporous frameworks are polymeric materials built from rigid molecules, which give rise to their nanoporous structures with applications in gas sorption and storage, catalysis and others. Conceptually new applications could emerge, should these beneficial properties be manipulated by external stimuli in a reversible manner. One approach to render nanoporous frameworks responsive to external signals would be to immobilize molecular switches within their nanopores. Although the majority of molecular switches require conformational freedom to isomerize, and switching in the solid state is prohibited, the nanopores may provide enough room for the switches to efficiently isomerize. Here we describe two families of nanoporous materials incorporating the spiropyran molecular switch. These materials exhibit a variety of interesting properties, including reversible photochromism and acidochromism under solvent-free conditions, light-controlled capture and release of metal ions, as well reversible chromism induced by solvation/desolvation.}, author = {Kundu, Pintu K. and Olsen, Gregory L. and Kiss, Vladimir and Klajn, Rafal}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}, publisher = {Springer Nature}, title = {{Nanoporous frameworks exhibiting multiple stimuli responsiveness}}, doi = {10.1038/ncomms4588}, volume = {5}, year = {2014}, } @article{13403, abstract = {We show that bimolecular reactions between species confined to the surfaces of nanoparticles can be manipulated by the nature of the linker, as well as by the curvature of the underlying particles.}, author = {Zdobinsky, Tino and Sankar Maiti, Pradipta and Klajn, Rafal}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, keywords = {Colloid and Surface Chemistry, Biochemistry, General Chemistry, Catalysis}, number = {7}, pages = {2711--2714}, publisher = {American Chemical Society}, title = {{Support curvature and conformational freedom control chemical reactivity of immobilized species}}, doi = {10.1021/ja411573a}, volume = {136}, year = {2014}, } @article{13404, abstract = {In the past few years, spiropyran has emerged as the molecule-of-choice for the construction of novel dynamic materials. This unique molecular switch undergoes structural isomerisation in response to a variety of orthogonal stimuli, e.g. light, temperature, metal ions, redox potential, and mechanical stress. Incorporation of this switch onto macromolecular supports or inorganic scaffolds allows for the creation of robust dynamic materials. This review discusses the synthesis, switching conditions, and use of dynamic materials in which spiropyran has been attached to the surfaces of polymers, biomacromolecules, inorganic nanoparticles, as well as solid surfaces. The resulting materials show fascinating properties whereby the state of the switch intimately affects a multitude of useful properties of the support. The utility of the spiropyran switch will undoubtedly endow these materials with far-reaching applications in the near future.}, author = {Klajn, Rafal}, issn = {1460-4744}, journal = {Chemical Society Reviews}, keywords = {General Chemistry}, number = {1}, pages = {148--184}, publisher = {Royal Society of Chemistry}, title = {{Spiropyran-based dynamic materials}}, doi = {10.1039/c3cs60181a}, volume = {43}, year = {2014}, } @article{9050, abstract = {Self-propelled particles can exhibit surprising non-equilibrium behaviors, and how they interact with obstacles or boundaries remains an important open problem. Here we show that chemically propelled micro-rods can be captured, with little change in their speed, into close orbits around solid spheres resting on or near a horizontal plane. We show that this interaction between sphere and particle is short-range, occurring even for spheres smaller than the particle length, and for a variety of sphere materials. We consider a simple model, based on lubrication theory, of a force- and torque-free swimmer driven by a surface slip (the phoretic propulsion mechanism) and moving near a solid surface. The model demonstrates capture, or movement towards the surface, and yields speeds independent of distance. This study reveals the crucial aspects of activity–driven interactions of self-propelled particles with passive objects, and brings into question the use of colloidal tracers as probes of active matter.}, author = {Takagi, Daisuke and Palacci, Jérémie A and Braunschweig, Adam B. and Shelley, Michael J. and Zhang, Jun}, issn = {1744-6848}, journal = {Soft Matter}, keywords = {General Chemistry, Condensed Matter Physics}, number = {11}, publisher = {Royal Society of Chemistry }, title = {{Hydrodynamic capture of microswimmers into sphere-bound orbits}}, doi = {10.1039/c3sm52815d}, volume = {10}, year = {2014}, } @article{10385, abstract = {We show how self-assembly of sticky nanoparticles can drive radial collapse of thin-walled nanotubes. Using numerical simulations, we study the transition as a function of the geometric and elastic parameters of the nanotube and the binding strength of the nanoparticles. We find that it is possible to derive a simple scaling law relating all these parameters, and estimate bounds for the onset conditions leading to the collapse of the nanotube. We also study the reverse process – the nanoparticle release from the folded state – and find that the stability of the collapsed state can be greatly improved by increasing the bending rigidity of the nanotubes. Our results suggest ways to strengthen the mechanical properties of nanotubes, but also indicate that the control of nanoparticle self-assembly on these nanotubes can lead to nanoparticle-laden responsive materials.}, author = {Napoli, Joseph A. and Šarić, Anđela and Cacciuto, Angelo}, issn = {1744-6848}, journal = {Soft Matter}, keywords = {condensed matter physics, general chemistry}, number = {37}, pages = {8881--8886}, publisher = {Royal Society of Chemistry}, title = {{Collapsing nanoparticle-laden nanotubes}}, doi = {10.1039/c3sm51495a}, volume = {9}, year = {2013}, } @article{10386, abstract = {In this paper we review recent numerical and theoretical developments of particle self-assembly on fluid and elastic membranes and compare them to available experimental realizations. We discuss the problem and its applications in biology and materials science, and give an overview of numerical models and strategies to study these systems across all length-scales. As this is a very broad field, this review focuses exclusively on surface-driven aggregation of nanoparticles that are at least one order of magnitude larger than the surface thickness and are adsorbed onto it. In this regime, all chemical details of the surface can be ignored in favor of a coarse-grained representation, and the collective behavior of many particles can be monitored and analyzed. We review the existing literature on how the mechanical properties and the geometry of the surface affect the structure of the particle aggregates and how these can drive shape deformation on the surface.}, author = {Šarić, Anđela and Cacciuto, Angelo}, issn = {1744-6848}, journal = {Soft Matter}, keywords = {condensed matter physics, general chemistry}, number = {29}, publisher = {Royal Society of Chemistry}, title = {{Self-assembly of nanoparticles adsorbed on fluid and elastic membranes}}, doi = {10.1039/c3sm50188d}, volume = {9}, year = {2013}, } @article{9167, abstract = {We introduce a self-propelled colloidal hematite docker that can be steered to a small particle cargo many times its size, dock, transport the cargo to a remote location, and then release it. The self-propulsion and docking are reversible and activated by visible light. The docker can be steered either by a weak uniform magnetic field or by nanoscale tracks in a textured substrate. The light-activated motion and docking originate from osmotic/phoretic particle transport in a concentration gradient of fuel, hydrogen peroxide, induced by the photocatalytic activity of the hematite. The docking mechanism is versatile and can be applied to various materials and shapes. The hematite dockers are simple single-component particles and are synthesized in bulk quantities. This system opens up new possibilities for designing complex micrometer-size factories as well as new biomimetic systems.}, author = {Palacci, Jérémie A and Sacanna, Stefano and Vatchinsky, Adrian and Chaikin, Paul M. and Pine, David J.}, issn = {15205126}, journal = {Journal of the American Chemical Society}, keywords = {Colloid and Surface Chemistry, Biochemistry, General Chemistry, Catalysis}, number = {43}, pages = {15978--15981}, publisher = {American Chemical Society}, title = {{Photoactivated colloidal dockers for cargo transportation}}, doi = {10.1021/ja406090s}, volume = {135}, year = {2013}, }