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Chirality Unlocks Sub-Terahertz Molecular Dynamics in Peptide Nanotubes
Abstract Low-frequency modes in the picosecond range play a key role in molecular recognition and biomolecular function. Here, we investigate how these dynamics at the interfaces of self-assembled peptide biomaterials relate to fine structural details of the supramolecular assembly. We resolve terahertz and mid-infrared modes in individual diphenylalanine nanotubes by nanoscale microspectroscopy, uncovering a direct correlation between supramolecular chirality, molecular arrangement, and picosecond dynamics at the nanotube-environment boundary. By combining THz and mid-IR nanoscopy with a multiscale strategy spanning single nanotubes and ensemble measurements, supported by density functional theory calculations, we access the intrinsic picosecond response of peptide assemblies beyond the limits of conventional microscopy and ensemble averaging. Heterochiral (D-L) nanotubes display sharp resonances, whereas homochiral (L-L) nanotubes exhibit a comparatively featureless sub-THz profile, revealing a clear chirality-dependent contrast. Mode assignments show that the heterochiral features are dominated by localized torsional and bending motions of phenyl rings relative to the peptide backbone. Overall, chirality-dependent THz fingerprints emerge as sensitive descriptors of peptide nanotube architecture, while low-frequency nanospectroscopy provides a route to interrogate biomaterial interfaces under biologically relevant conditions. Autori Rajat Kumar, Erica Scarel, Andrea Perucchi, Lisa Vaccari, Prasanta Kumar Datta, Francesco D’amico, Paola Di Pietro, Silvia Marchesan, Federica Piccirilli Rivista ChemrXiv Data di pubblicazione 11/03/2026 Consulta la pubblicazione
Ultrafast Intermolecular Dynamics of Nanoconfined Water in Swollen Lipid Cubic Mesophases
Abstract Understanding the structure and dynamics of the hydrogen-bond network ofwater in topologically distinct swollen lipidic mesophases, is fundamental fortheir application in biomedical, pharmaceutical, and food science fields. Here,a positive and non-linear correlation between water hydrogen-bond dynamicsand interfacial water population is uncovered in inverse bicontinuous swollenmesophases across an extended temperature range (298–340 K). Particularly,small-angle X-ray scattering determines the mesophase’s structural features,uncovering a temperature-driven re-entrant phenomenon (reappearance) ofPn̄ 3m phase upon heating. This topologically rich environment, however, hasno detectable impact on the temperature dependence of the intermolecularmodes of water, as revealed by terahertz absorption spectroscopy. Specifically,these modes show distinct dynamics: the stretching mode exhibits longerlifetimes than the libration mode, yet with a higher temperature-dependence,with approximately two-fold lower Arrhenius activation energies. In contrast,both stretching and libration modes exhibit a monotonic decrease in lifetimewith increasing temperature, due to the increasing disruption of thehydrogen-bond network. Atomistic molecular dynamics simulations enablethe quantification of interfacial water population, which shows a positivecorrelation with intermolecular lifetimes in a nonlinear manner, revealing anon-additive coupling between interfacial water population and waterhydrogen-bond network dynamics within these systems. Autori Eva Zunzunegui-Bru, Serena Rosa Alfarano, Patrick Züblin, Laura Baraldi,Hendrik Vondracek, Federica Piccirilli, Lisa Vaccari, and Raffaele Mezzenga Rivista Small Data di pubblicazione 03/10/2025 Consulta la pubblicazione
Eco-friendly NaCl glycerol-based deep eutectic electrolyte for high-voltage electrochemical double layer capacitor
Abstract Herein, we propose eco-friendly electrolytes based on sodium chloride as a hydrogen bond acceptor and glycerol as a hydrogen bond donor, as alternatives to toxic, flammable and unsustainable electrolytes commonly used in electrochemical energy storage systems. By means of an in-depth multi-technique investigation, including Raman and FT-FIR spectroscopy, of the formulated electrolytes, we point out the effect of the structuring of the system on the transport and electrochemical properties. The 1 : 10 molar ratio mixture proves to be a deep eutectic solvent (DES), showing good room temperature ionic conductivity (0.186 mS cm−1) and electrochemical stability (≈3 V). When implemented as electrolyte in an activated-carbon electrochemical double layer capacitor, this DES exhibits superior performance compared to mixtures with different molar ratio and those containing ethylene glycol as the hydrogen bond donor, with a high operational voltage (2.6 V), a specific capacitance of 14.1 F g−1, and a remarkable cycling stability. These findings highlight the potential of glycerol-based DESs as alternative electrolytes for sustainable electrochemical energy storage applications. Autori Daniele Motta, Alessandro Damin, Hamideh Darjazi, Stefano Nejrotti, Federica Piccirilli, Giovanni Birarda, Claudia Barolo, Claudio Gerbaldi, Giuseppe Antonio Elia, Matteo Bonomo Rivista Green Chemistry Data di pubblicazione 31/03/2025 Consulta la pubblicazione
Co-assembled supramolecular hydrogels: nano-IR sheds light on tripeptide assemblies
Abstract Supramolecular hydrogels composed of self-assembling short peptides are gaining momentum for enzyme mimicry. In particular, multicomponent systems that feature similar peptides with a self-assembling motif (e.g., Phe–Phe) and catalytic residues (e.g., His, Asp) offer a convenient approach to organize in space, functional residues that typically occur at enzymatic active sites. However, characterisation of these systems, and especially understanding whether the different peptides co-assemble or self-sort, is not trivial. In this work, we study two-component hydrogels composed of similar tripeptides and describe how nano-IR can reveal important details of their packing, thus demonstrating it to be a useful technique to characterise multicomponent, nanostructured gels. Autori Paola Alletto, Ana M. Garcia, Federica Piccirilli, Silvia Marchesan Rivista Faraday Discussions Data di pubblicazione 21/02/2025 Consulta la pubblicazione
Striped Twisted State in the Orientational Epitaxy on Quasicrystals
Abstract The optimal “twisted” geometry of a crystalline layer on a crystal has long been known, but that on a quasicrystal is still unknown and open. We predict analytically that the layer equilibrium configuration will generally exhibit a nonzero misfit angle. The theory perfectly agrees with numerical optimization of a colloid monolayer on a quasiperiodic decagonal optical lattice. Strikingly different from crystal-on-crystal epitaxy, the structure of the novel emerging twisted state exhibits an unexpected stripe pattern. Its high anisotropy should reflect on the tribomechanical properties of this unconventional interface. Authors Nicola Manini, Mario Forzanini, Sebastiano Pagano, Marco Bellagente, Martino Colombo, Dario Bertazioli, Tommaso Salvalaggio, Andrea Vanossi, Davide Vanossi, Emanuele Panizon, Erio Tosatti, Giuseppe E. Santoro Journal Physical Review Letters Publication Date 12/02/2025 Consult the publication
CO2 and Temperature Induced Switching of a Flexible Metal–Organic Framework with Surface-Mounted Nanoparticles
Abstract Within the material family of metal–organic frameworks (MOFs) the subclass of flexible MOFs (flexMOFs) has attracted great attention, showing structural flexibility as a response to external stimuli such as guest adsorption, temperature, and pressure. Hybrid composites like nanoparticle (NP) loaded flexible MOFs, which stand to potentially combine advantageous properties of both are yet largely unexplored. Here the synthesis of flexMOFs with surface mounted nanoparticles, e. g. NP@Zn2(BME-bdc)2dabco composites (NP = Pt and SiO2 nanoparticles, BME-bdc2− = 2,5-bismethoxyethoxy-1,4-benzenedicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane) is reported, studying the impact of nanoparticles on the stimulus-responsiveness of a flexMOF. It is shown that CO2 physisorption triggered flexibility of the MOF is retained and reversible for all NP@flexMOF composites. Additionally, it is observed that NPs stabilize the large pore state of the MOF, slightly increasing and shifting the switching pressure window. This effect is also observed during temperature-induced switching but Pt@flexMOF composites partially lose long-range order during the reversion to their narrow pore state, while attached SiO2 NPs allow for a fully reversible transition. These findings suggest that the total exerted material strain triggering the switching is heavily dependent on NP size and the applied stimulus and that guest-induced switchability can be fully realized in NP@flexMOF hybrid materials. Autori Jan Berger, Stephanie Terruzzi, Hana Bunzen, Filippo Ballerini, Marco Vandone, Marcello Marelli, Luca Braglia, Roland A. Fischer, Valentina Colombo, Gregor Kieslich Rivista Small Data di pubblicazione 07/01/2025 Consulta la pubblicazione
Degradation of α-MnO2 in Zn-air battery gas-diffusion electrodes: An investigation based on chemical-state mapping
Abstract Here, we present an integrated ultra-high-vacuum (UHV) apparatus for the growth of complex materials and heterostructures. The specific growth technique is the Pulsed Laser Deposition (PLD) by means of a dual-laser source based on an excimer KrF ultraviolet and solid-state Nd:YAG infra-red lasers. By taking advantage of the two laser sources—both lasers can be independently used within the deposition chambers—a large number of different materials—ranging from oxides to metals, to selenides, and others—can be successfully grown in the form of thin films and heterostructures. All of the samples can be in situ transferred between the deposition chambers and the analysis chambers by using vessels and holders’ manipulators. The apparatus also offers the possibility to transfer samples to remote instrumentation under UHV conditions by means of commercially available UHV-suitcases. The dual-PLD operates for in-house research as well as user facility in combination with the Advanced Photo-electric Effect beamline at the Elettra synchrotron radiation facility in Trieste and allows synchrotron-based photo-emission as well as x-ray absorption experiments on pristine films and heterostructures. Autori Benedetto Bozzini, Alessandro Alleva, Valentina Bonanni, Regina Ciancio, George Kourousias, Francesco Guzzi, Piu Rajak, Alessandra Gianoncelli Rivista Electrochimica Acta Data di pubblicazione 20/12/2024 Consulta la pubblicazione
Raman Microscopy Identification of Secondary Spurious Phases in Molten GdSr2RuCu2O8-δ Superconductor for Photonics and Plasmonic Applications
Abstract Plasmonic and Photonics applications of superconducting materials, suggested at first by the necessity to minimize the dissipative losses of conventional metals in the high frequency ranges, are topics of growing interest in Optics. In this perspective, GdSr2RuCu2O8-δ (Gd1212) Rutheno-Cuprate Superconductor presents very promising properties, showing both superconducting and magnetically ordered phases coexisting in the same cell. To investigate its features, the fabrication of macroscopic crystallographically oriented samples is necessary. The use of melt texturing techniques has shown to be among the most effective ways to achieve the best characteristics, although the fabrication of high-quality Gd1212 samples is intrinsically difficult. To reach a better understanding of Gd1212 incongruent melting reaction, a series of bulk samples annealed at temperatures below and above the melting temperature was prepared. Raman Microscopy and Mapping performed on molten and re-solidified samples revealed the presence of different phases, corresponding to those identified in our previous studies. These observations were also confirmed by XRD, TGA-DTA, and SEM+EDS characterisations. Secondary phases formation showed a strong dependence on the temperature of the annealing treatments. Susceptibility and magnetization measurements show both superconducting and magnetic transitions and a contribution of different spurious magnetic phases as suggested by EDS. Autori Marcello Gombos, Stefano Managò, Danilo Zola, Giovanni Carapella, Oreste Tarallo, Vito Mocella, Anna Chiara De Luca, Ivo Rendina, Francesco Ruffo, Pasquale Orgiani, Regina Ciancio Rivista Accepted at the Annual Meeting of the Association for Computational Linquistics (ACL), Arxiv preprint: 2402.11655 Data di pubblicazione 31/10/2024 Consulta la pubblicazione
Effects of In-Air Post Deposition Annealing Process on the Oxygen Vacancy Content in Sputtered GDC Thin Films Probed via Operando XAS and Raman Spectroscopy
Abstract We investigate the ionic mobility in room-temperature RF-sputtered gadolinium doped ceria (GDC) thin films grown on industrial solid oxide fuel cell substrates as a function of the air-annealing at 800 and 1000 °C. The combination of X-ray diffraction, X-ray photoelectron spectroscopy, operando X-ray absorption spectroscopy, and Raman spectroscopy allows us to study the different Ce3+/ Ce4+ ratios induced by the post growth annealing procedure, together with the Ce valence changes induced by different gas atmosphere exposure. Our results give evidence of different kinetics as a function of the annealing temperature, with the sample annealed at 800 °C showing marked changes of the Ce oxidation state when exposed to both reducing and oxidizing gas atmospheres at moderate temperature (300 °C), while the Ce valence is weakly affected for the 1000 °C annealed sample. Raman spectra measurements allow us to trace the responses of the investigated samples to different gas atmospheres on the basis of the presence of different Gd–O bond strengths inside the lattice. These findings provide insight into the microscopic origin of the best performances already observed in SOFCs with a sputtered GDC barrier layer annealed at 800 °C and are fundamental to further improve sputtered GDC thin film performance in energy devices. Autori Nunzia Coppola, Sami Ur Rehman, Giovanni Carapella, Luca Braglia, Vincenzo Vaiano, Dario Montinaro, Veronica Granata, Sandeep Kumar Chaluvadi, Pasquale Orgiani, Piero Torelli, Luigi Maritato, Carmela Aruta, Alice Galdi Rivista ACS Applied Electronic Materials Data di pubblicazione 25/09/2024 Consulta la pubblicazione
La0.2Sr0.25Ca0.45TiO3 Surface Reactivity with H2: A Combined Operando NEXAFS and Computational Study
Abstract A-site doped SrTiO3 is considered as a promising substitute for traditional anodic metals in solid oxide fuel cells (SOFCs). In this study, we present the reactivity of La0.2Sr0.25Ca0.45TiO3 (LCSTO), La0.2Sr0.7TiO3 (LSTO), and SrTiO3 (STO) toward H2 by operando ambient pressure NEXAFS spectroscopy and theoretical spectra simulation with FDMNES code. The samples were synthesized by MBE (molecular beam epitaxy), hydrothermal, and modified-Pechini routes. We found that the reducibility of the samples depends not only on their stoichiometry but also on the morphology, which is determined by the synthetic method. The results of these experiments give insight into the reducibility of Ti4+ in perovskites as well as the opportunity to further optimize the synthesis of these materials to obtain the best performance for SOFC applications. Autori F. Bassato, S. Mauri, L. Braglia, A. Yu. Petrov, E. Dobovičnik, F. Tavani, A. Tofoni, P. Ferrer, D. Grinter, G. Held, P. D’Angelo, P. Torelli Rivista The Journal of Physical Chemistry Letters Data di pubblicazione 13/08/2024 Consulta la pubblicazione
Universality in the Structure and Dynamics of Water under Lipidic Mesophase Soft Nanoconfinement
Abstract Water under soft nanoconfinement features physical and chemical properties fundamentally different from bulk water; yet, the multitude and specificity of confining systems and geometries mask any of its potentially universal traits. Here, we advance in this quest by resorting to lipidic mesophases as an ideal nanoconfinement system, allowing inspecting the behavior of water under systematic changes in the topological and geometrical properties of the confining medium, without altering the chemical nature of the interfaces. By combining Terahertz absorption spectroscopy experiments and molecular dynamics simulations, we unveil the presence of universal laws governing the physics of nanoconfined water, recapitulating the data collected at varying levels of hydration and nanoconfinement topologies. This geometry-independent universality is evidenced by the existence of master curves characterizing both the structure and dynamics of simulated water as a function of the distance from the lipid–water interface. Based on our theoretical findings, we predict a parameter-free law describing the amount of interfacial water against the structural dimension of the system (i.e., the lattice parameter), which captures both the experimental and numerical results within the same curve, without any fitting. Our results offer insight into the fundamental physics of water under soft nanoconfinement and provide a practical tool for accurately estimating the amount of nonbulk water based on structural experimental data. Autori Eva Zunzunegui-Bru, Serena Rosa Alfarano, Patrick Zueblin, Hendrik Vondracek, Federica Piccirilli, Lisa Vaccari, Salvatore Assenza, Raffaele Mezzenga Rivista ACS Nano Data di pubblicazione 01/08/2024 Consulta la pubblicazione
Enhancing Multi-Tip Artifact Detection in STM Images Using Fourier Transform and Vision Transformers
Abstract We address the issue of multi-tip artifacts in Scanning Tunneling Microscopy (STM) images by applying the fast Fourier transform (FFT) as a feature engineering method. We fine-tune various neural network architectures using a synthetic dataset, including Vision Transformers (ViT). The FFT-based preprocessing significantly improves the performance of ViT models compared to using only the grayscale channel. Ablation experiments highlight the optimal conditions for synthetic dataset generation. Unlike traditional methods that are challenging to implement for large datasets and used offline, our method enables on-the-fly classification at scale. Our findings demonstrate the efficacy of combining the Fourier transform with deep learning for enhanced artifact detection in STM images, contributing to more accurate analysis in material science research. Autori Tommaso Rodani, Alessio Ansuini, Alberto Cazzaniga Rivista ICML ’24 Workshop ML for Life and Material Science: From Theory to Industry Applications Data di pubblicazione 17/07/2024 Consulta la pubblicazione