Abstracts of the Talks at the Satellite "Chemical Complexity"
On this page you find the abstracts of the talks that will be presented at the Satellite event. For details please click on the arrow to see the abstract. For information on the speakers visit the section "speakers" or click on the name of the speakers below.
Phyllotactic structures in radially growing pattern-forming systems (Talk by Anne De Wit)
Phyllotactic structures in radially growing pattern-forming systemsG. Facchini*1, M. Budroni*2, G. Schuszter3, F. Brau1, and A. De Wit1 1 Nonlinear Physical Chemistry Unit, Université libre de Bruxelles (ULB), CP231, 1050 Brussels, Belgium. Phyllotactic patterns, i.e. regular arrangements of leaves or flowers around a plant stem, are beautiful and fascinating examples of regular complex structures encountered in Nature. In botany, their specific symmetries develop when a new primordium periodically grows in the largest gap left between the previous primordium and the apex [1]. Experiments using ferrofluid droplets have also shown that phyllotactic patterns spontaneously form when identical elements repulsing each other are periodically released at a given distance from an injection center and are advected radially at a constant speed [2]. A central issue in phyllotaxis is to understand whether other self-organized mechanisms can generate such patterns. We show that phyllotactic patterns can also develop in the large class of spatial symmetry-breaking systems giving spotted structures with an intrinsic wavelength in the case of radial growth. The constraint of maintaining a fixed wavelength between spots while expanding radially either diffusively or advectively generalizes the concept of successive release of repulsing agents in botany or ferrofluids to new classes of systems. We evidence this numerically on two different models describing reaction-driven phase transitions [3] and self-organized spatial Turing patterns [4], respectively. We further confirm it experimentally with phyllotactic patterns obtained within a radial flow using a precipitation reaction, similar to mineralization reactions important for CO2 sequestration [5]. A generalized method for the construction of this new family of phyllotactic structures is presented. Revealing the genericity of the simple conditions needed to obtain such new phyllotactic arrangements paves the way to discover them in large classes of systems ranging from spinodal decomposition [3], chemical [6], biological [7] or optical [8] Turing structures, and ecological [9] or Liesegang [10] patterns, to name a few. References [1] Jean, R.V., Phyllotaxis, (Cambridge University Press, 2010). [2] Douady, S. & Couder, Y., Phyllotaxis as a physical self-organized growth process, Phys. Rev. Lett., 68, 2098 (1992). [3] Cahn, J.W. & Hilliard, J.E., Free Energy of a Nonuniform System. I. Interfacial Free Energy, The Journal of Chemical Physics, 28, 258 (1958). [4] Turing, A., The chemical basis of morphogenesis., Philos Trans R Soc Lond B. 237, 37 (1952). [5] Schuszter, G., Brau, F. & De Wit, A. Calcium Carbonate Mineralization in a Confined Geometry,Environ. Sci. Technol. Lett. 3, 156 (2016). [6] Castets, V. et al., Experimental evidence of a sustained standing Turing-type nonequilibrium chemical pattern, Phys. Rev. Lett. 64, 2953 (1990); [7] Kondo, S. & Asai, A reaction-diffusion wave on the skin of the marine angelfish Pomacanthus, Nature 376, 765 (1995). [8] Staliunas, K. Three-dimensional Turing structures and spatial solitons in optical parametric oscillators. Phys. Rev. Lett. 81, 81 (1998). [9] Lefever, R. & Lejeune, O. On the origin of tiger bush, Bull. Math. Biol. 59, 263 (1997). [10] Dayeh, M., Ammar, M. and Al-Ghoul, M., Transition from rings to spots in a precipitation reaction–diffusion system, RSC Adv. 4, 60034 (2014). |
How intracellular wave patterns mediate switches between different modes of cell migration (Talk by Carsten Beta)
How intracellular wave patterns mediate switches between different modes of cell migrationpresenting author: Carsten Beta1
1University of Potsdam, Germany Self-organized patterns in the actin cytoskeleton are essential for eukaryotic cellular life. They are the building blocks of many functional structures that often operate simultaneously to facilitate, for example, nutrient uptake or movement of cells. Here, we present experimental results demonstrating that ring-shaped actin waves mediate switches between different modes of cell motility, and may even trigger spontaneous, cell cycle-independent cytofission in multinucleate amoeboid cells. However, identifying how qualitatively distinct actin patterns may coexist and how they induce transitions between different modes of migration remains a challenge. Using bifurcation theory of a mass conserved activator-inhibitor system, we propose answers to these questions based on generic mechanisms of pattern formation. |
Collective chemomechanical oscillations in active hydrogels (Talk by Baptiste Blanc)
Collective chemomechanical oscillations in active hydrogelsBaptiste Blanc1 , Johnson Agyapong2, Alberto Fernandez-Nieves3 , Seth Fraden4
1Université Cote d’Azur, Nice, France. We report on the collective response of an assembly of chemomechanical Belousov Zhabotinsky (BZ) hydrogel beads. We first demonstrate that a single spherical BZ hydrogel bead with a radius below a critical value is not oscillating, whereas an assembly of the same BZ hydrogel beads presents chemical oscillation. A BZ chemical model with an additional flux of chemicals out of the BZ hydrogel captures the experimentally observed transition from oxidized non oscillating to oscillating BZ hydrogels and shows this transition is due to a flux of inhibitors out of the BZ hydrogel. The model also captures the role of neighboring BZ hydrogel beads in decreasing the critical size for an assembly of BZ hydrogel beads to oscillate. We finally leverage the quorum sensing behavior of the collective to trigger their chemomechanical oscillation, and discuss how this collective effect can be used to enhance the oscillatory strain of these active BZ hydrogels. These findings could help guide the eventual fabrication of a swarm of autonomous, communicating and motile hydrogels. |
Chemical Complexity for Chemical AI (Talk by Pier-Luigi Gentili)
Chemical Complexity for Chemical AIPier-Luigi Gentili1
1Department of Chemistry, Biology, and Biotechnology, Università degli Studi di Perugia, Perugia, Italy Living systems exhibit remarkable and mesmerizing features that have been drawing the attention of scientists and philosophers for a long time.[1,2] Among them, purposefulness is certainly amazing. The fundamental purposes that every healthy living being pursues are survival and reproduction. The goal-directedness is managed by living beings’ power to utilize matter and energy to encode, collect, store, process, and communicate information. All living beings are “Information Gathering and Utilizing Systems” (IGUSs)[3] that show variegated forms of intelligent performances: They can reach goals by learning (for instance, by adapting, acclimating, and evolving) and undertaking actions that are not entirely determined by local circumstances. The research line of Chemical Artificial Intelligence (CAI) is trying to answer the following heuristic question:[4] “Which performances of biological intelligence can be mimicked through inanimate chemical systems in wetware, i.e., in a liquid solution, which is the characteristic phase of life?” In this contribution, it will be demonstrated that by playing with Chemical Complexity, it is possible to obtain emergent properties that become reasonable surrogates of some performances of biological intelligence.[5-8] References [1] E. Schrödinger, What is Life? Cambridge University Press, 1944. [2] H. R. Maturana, F. Varela, Autopoiesis and cognition: the realisation of the living. D. Reidel Publishing Company Dordrecht, Netherlands 1980. [3] M. Gell-Mann, The quark and the jaguar. Holt, New York (USA) 1994. [4] P. L. Gentili, P. Stano, Biochem. Biophys. Res. Commun. 2024, 720, 150060. [5] P. L. Gentili, P. Stano, ChemSystemsChem 2024, 6, e202400054. [6] P. L. Gentili, Adv. Opt. Mater. 2025, under review. [7] P. L. Gentili, J. Perez-Mercader, Front. Chem.2022, 10, 950769. [8] P. L. Gentili, Dyes & Pigments 2022, 205, 110547. |
pH waveforms in batch and cell-sized microcompartments using an enzymatic reaction network (Talk by István Lagzi)
pH waveforms in batch and cell-sized microcompartments using an enzymatic reaction networkIstván Lagzi1,2, Gábor Holló3, Masaki Itatani4, Paola Albanese4,5, Nadia Valletti4, Federico Rossi4
1 Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Budapest, Hungary One of the main challenges in synthetic biology is incorporating enzymatic reaction networks inside artificial cells. We partially addressed this issue and engineered a single pH pulse in cell-sized microcompartments by employing the coupling strategy of antagonistic enzymatic reactions. In our setup, we encapsulated two enzymes, urease and esterase, inside GUVs. We added the substrates, urea, and ethyl acetate to the outer solution to initiate the process. Since they are electrically neutral chemical species, they could pass the bilayer and initiate the enzymatic reactions inside the microcompartments. This is an example of a primitive biochemical oscillatory system operated out-of-equilibrium in artificial cells utilizing an enzymatic reaction network and selective cross-membrane transport of the chemical species. The system described is not as complex as the networks found in cells. Nonetheless, these findings can provide impetus in designing and engineering enzymatic reaction networks, functional synthetic cells, and soft-robotics applications. |
Kinetic and diffusion-driven instabilities in flow (Talk by István Szalai)
Kinetic and diffusion-driven instabilities in flowIstván Szalai1 and Fatima Shoeb1
1Institute of Chemistry, Eötvös Loránd University in Budapest, Hungary. Replication and exponential growth caused by autocatalytic networks are essential natural self-organization processes from the molecular to the population level. Beyond the temporal dynamics, a wide range of spatiotemporal patterns may appear when transport processes are combined with autocatalytic networks. Both diffusion, a molecular-level transport process, and bulk fluid motion, advection can play a constructive role in developing these phenomena. We provide experimental evidence of oscillations in pH-autocatalytic reaction networks performed in a flow reactor. The linear residence time ramp may result in the simultaneous appearance of different dynamic states along the length of the pipe. Thus, tubular reactors offer a unique opportunity to quickly explore the dynamics of reaction networks. Numerical simulations reveal different instabilities that can originate the experimentally observed spatiotemporal oscillations. Besides kinetic instabilities, long-range activation due to the fats diffusion of hydrone ions can also play a significant role. |
Coordination and synchronization of chitosan surfers (Talk by Ágota Tóth)
Coordination and synchronization of chitosan surfersJúlia Katona1, Bálint Gárdi1, Pawan Kumar1,2, Dezső Horváth3 and Ágota Tóth1
1Department of Physical Chemistry and Materials Science, University of Szeged, Szeged, Hungary Active constituents effectively harness energy to generate self-propulsion on micro- to macroscales. Localized interactions between individuals can spontaneously lead to collective motion. The motility of inanimate particles can be achieved by several techniques, such as the Marangoni effect or bubble generation. In the former case, the necessary asymmetry is introduced by surface tension gradients, while in the latter case, by the ejection of reaction-induced gas bubbles. Here, we show that in-situ sol-gel transition of chitosan droplets can result in the formation of a surfer exhibiting self-propulsion. A drop of chitosan solution in a pool of sodium hydroxide solution results in passive hydrogel beads.When surface active ethanol is added to the chitosan solution, the evolving active beads exhibit self-propulsion at the air-liquid interface. [1] Several of these surfers can assemble around a single passive bead in a rotatory way, where the passive bead acts as a coordinator. Placing three or more surfers close to each other leads to synchronized oscillatory patterns due to the inherent Marangoni convection and the arising capillary attraction. [2] Different modes of synchrony are observed in varying the size of active surfers. Our work suggests a new way to design artificial soft self-propellers exhibiting complex dynamics due to the interplay of capillary attraction and Marangoni repulsion. References [1] P. Kumar, D. Horváth, and Á. Tóth, Sol-gel transition programmed self-propulsion of chitosan hydrogel, Chaos 32, 063120 (2022). |
Unpinning Possibility of Spiral Waves with a Mild Concentration Gradient in BZ Chemical Reaction-Diffusion System (Talk by Parvej Khan)
Unpinning Possibility of Spiral Waves with a Mild Concentration Gradient in BZ Chemical Reaction-Diffusion SystemParvej Khan1, Sumana Dutta1 1Indian Institute of Technology Guwahati, Assam 781039, India Excitable waves are those that undergo a refractory period and lack damping. From our heart to the neuronal system to the retina, excitable waves are present. Spiral and scroll patterns in Belousov- Zhabotinsky (BZ) reactions are also excitable systems. A broken cardiac wave of abnormal rhythm is comparable to spiral waves in a BZ reaction. So, the study of the dynamics of these excitable waves is important. We study controlling dynamics as well as collective dynamics of spirals and scrolls (3-D counterpart of spiral waves) in a chemical reaction-diffusion system. |
The Effect of a High Stirring Rate on the Closed Ferroin-Catalyzed Belousov-Zhabotinsky Reaction (Talk by Florian Wodlei)
The Effect of a High Stirring Rate on the Closed Ferroin-Catalyzed Belousov-Zhabotinsky ReactionFlorian Wodlei1, Bao Quoc Tang2 and Mihnea Raul Hristea1
1Living Systems Research, Klagenfurt, Austria It is intuitive that stirring has the purpose to homogenize and therefore increase the efficiency of liquid chemical reaction systems. However, it can possess other effects due to the highly nonlinear interactions in complex chemical reaction systems. These systems can show different dynamics such as bistability, excitability or periodicity. A prominent example is the Belousov-Zhabotinsky reaction in which stirring effects are being investigated since long [1,2,3].
When a closed Ferroin-catalyzed Belousov-Zhabotinsky Reaction in batch is stirred with a high stirring rate within the periodic regime, the oscillatory behavior ceases to exist [3]. Through experiments, we observe that the system moves to a non-periodic reduced steady state in which it stays as long as stirring is present. As soon as stirring has stopped the oscillations reappear. For moderate stirring rates the system remains in the oscillatory regime while the amplitude is increased during stirring and the period times are decreased after the stirring has stopped. Furthermore, we also discover that the critical stirring rate for which the system switches to the non-periodic reduced steady state depends on the moment in which stirring is started in the periodic phase. [1] Michael Menzinger and Peter Jankowski: “Concentration Fluctuations and Stirring Effects in the Belousov-Zhabotinsky Reaction “. The Journal of Physical Chemistry 1990 94 (10), 4123-4126 [2] P. Strizhak and M. Menzinger: “Stirring Effect on the Bistability of the Belousov-Zhabotinsky Reaction in a CSTR”. The Journal of Physical Chemistry 1996 100 (49), 19182-19186 [3] Peter Ruoff: “Excitability in a closed stirred Belousov—Zhabotinskii system”, Chemical Physics Letters, Volume 90, Issue 1, 1982, Pages 76-80 [4] Zoltan Noszticzius, Zsolt Bodnar, Laszlo Garamszegi, and Maria Wittmann: “Hydrodynamic turbulence and diffusion-controlled reactions: simulation of the effect of stirring on the oscillating Belousov-Zhabotinskii reaction with the Radicalator model” The Journal of Physical Chemistry 1991 95 (17), 6575-6580 [5] Kalishyn, Yevhen Yu., Rachwalska, Małgorzata and Strizhak, Peter E.: "Stirring Effect on the Belousov-Zhabotinsky Oscillating Chemical Reactions in a Batch. Experimental and Modelling" Zeitschrift für Naturforschung A, vol. 65, No. 1-2, 2010, pp. 132-140 |
Controlling the Mode of Motion of Self-propelled BZ Droplet (Talk by Nobuhiko J. Suematsu)
Controlling the Mode of Motion of Self-propelled BZ DropletNobuhiko J. Suematsu1, Satoshi Udagawa2
1Graduate School of Advanced Mathematical Sciences, Meiji University, Japan Self-propelled motion derived from interfacial dynamics has been demonstrated through various chemical reactions [1]. Additionally, biomimetic functionalities have been realized using self-propelled objects,such as chemotaxis, phototaxis, and the ability to gather and carry target molecules.
Figure 1: (a) Illustration of the strategy to construct phototactic self-propelled droplets. The Belousov-Zhabotinsky (BZ) reaction controls the movement of self-propelled aqueous droplets swimming in an oil phase. At the same time, the BZ reaction is sensitive to light intensity. Thus, the droplets’ movement behaviors respond to the external light intensity through the photosensitive BZ reaction. (b) Experimental results. By varying the light intensity, we achieved real-time switching between random and oscillatory motion. References[1] N. J. Suematsu, S. Nakata, Chemistry - A Eur. J. 2018, 24, 6308. |
Chemical computing without logic gates* (Talk by Jerzy Górecki)
Chemical computing without logic gates*Jerzy Górecki1
1Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland Semiconductor logic gates are fast and reliable. They are characterized by a long error-free
operation time and can be downsized to nanoscale. Electrical input and output signals allow for
easy inter-gate communication and gate concatenation. Therefore, the bottom-up design strategy,
from gates through simple devices up to complex information processing systems, naturally
applies to semiconductor computing. *The title is inspired by a fantastic book of late David MacKay, FRS: Sustanable Energy Without the Hot Air |
Modelling synchronisation in populations of oscillating enzyme vesicles (Talk by Annette Taylor)
Modelling synchronisation in populations of oscillating enzyme vesiclesAnnette Taylor1, Co-author1 1School of Chemistry and Chemical Engineering, University of Southampton, UK Text |
Title (Talk by Emiliano Altamura)
TitleEmiliano Altamura1, Co-author1 1University of Bari "Aldo Moro", Italy Text |
Title (Talk by Pierandrea Lo Nostro )
TitlePierandrea Lo Nostro1, Co-author1 1Department of Chemistry, University of Florence, Italy Text |
Title (Talk by Marcello A. Budroni )
TitleMarcello A. Budroni1, Co-author1 1Department of Chemistry and Pharmacy, University of Sassari, Italy Text |
Title (Talk by Darío Martín Escala Vodopivec )
TitleDarío Martín Escala Vodopivec1, Co-author1 1School of Chemistry and Chemical Engineering, University of Southampton, UK Text |