Colombi Ciacchi, Lucio
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Colombi Ciacchi, Lucio
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Colombi Ciacchi, Lucio
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GND
8 results
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Item type:Publication, Hofmeister-Driven Ion Pairing in Monovalent Salts Directs Fibrinogen Nanofiber Assembly during Drying(ACS Publications, 2025-09); ; ; Aniol, JonasFibrinogen nanofiber scaffolds hold promise for tissue engineering and wound healing due to their similarity to fibrin clots. We studied how alkaline salts (Na, K) influence fibrinogen precipitation during drying of highly saline dispersions. In situ roughness (Aq) monitoring revealed coprecipitation of salts and fibrinogen. SEM and Aq mapping showed morphologies from smooth (KCl) and faintly fibrous (NaCl) to highly rough and finely fibrous (Na-PO, K-PO). FTIR indicated that secondary structure changes are not always linked to fiber formation. XPS showed a stronger Na uptake, especially with fiber-forming salts. With Na and oxygen-containing polyvalent anions, kosmotropic SO induced fibers, while chaotropic oxalate yielded smooth films. Mg or K with SO did not form any fibers. Molecular dynamics simulations suggest ion-specific binding at the fibrinogen/water interface. We propose a two-dimensional Hofmeister series for tailoring fibrillogenesis via kosmotropic anion-cation pairs, concluding that fiber assembly is salt-driven and governed by cooperative kosmotropic effects.journal articleBand:26Heft:1025 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Water Reactions on Reconstructed Rutile TiO2: A Density Functional Theory/Density Functional Tight Binding Approach(American Chemical Society, 2021-06-14); ; ; ; Far from being conclusively understood, the reactive interaction of water with rutile does still present a challenge to atomistic modeling techniques rooted in quantum mechanics. We show that static geometries of stoichiometric TiO2/water interfaces can be described well by density functional tight binding. However, this method needs further improvements to reproduce the low dissociation propensity of H2O after adsorption predicted by density functional theory (DFT). A reliable description of the surface reactivity of water is fundamental to investigate the nonstoichiometric reconstruction of the (001) facet rich in Ti interstitials. Calculations based on DFT predict the transition temperature for the onset of reconstruction in remarkable agreement with experiments and suggest that this surface, in contact with liquid water, can promote spontaneous H2O splitting and formation of H2 molecules.journal articleBand:125Heft:2438 45 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Compaction-induced restructuring of aggregated nanoparticle films using the discrete element methodAggregated nanoparticle films find application in many fields such as gas sensing, solar cells and batteries. These films are characterized by size distributions of polydisperse primary particles and sintered particle aggregates that dictate both the response to external load and functional properties such as heat or charge transport. Mechanical compaction of the films strongly affects these properties in a way that can be quantified by the change of porosity and pore size distributions on the applied compacting pressure. The exact restructuring mechanisms of the aggregate architecture, however, remain unknown. Here, we apply Discrete Element Method (DEM) simulations to gain access to such restructuring mechanisms in TiO2 nanoparticle films synthesized by flame-spray pyrolysis. The ability of the sintered TiO2 aggregates to rearrange via mutual detachment, rolling or sliding events dictated by non-covalent, humidity-dependent interactions are known to be crucial to predict the correct response to compaction. In this work, the importance of elastic deformation of aggregates according to a novel sinter bridge model is elucidated. The best match between DEM simulations and experiments is obtained for bridges with a tensile and bending strengths substantially larger than bulk TiO2, consistently with a low probability of critical fracture initiation in nanometer-scale structures.journal articleBand:34298 86 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Atomistic Modeling of the Formation of a Thermoset/Thermoplastic Interphase during Co-Curing(American chemical society, 2018); ; ; ; Co-curing of a thermoset epoxy matrix in contact with thermoplastic foils is an essential step in damage-free joining of polymers or polymer-based composites. We present results of all-atom molecular dynamics simulations that shed light onto the resulting hybrid interface. Using poly(vinylidene difluoride) (PVDF) and a multicomponent epoxy resin as model systems, we have developed a computational co-curing protocol that ensures both adequate structural representation and mobility of the PVDF chains and a realistic cross-linking conversion and topology of the epoxy resin. As a result, we reveal that mutually entangled loops of thermoplastic chains and resin strands form across the interface within the extended interphase region separating the two polymers. In tensile stress simulations we find that these loops contribute to a surprisingly large interfacial strength. In the absence of extrinsic defects, failures nucleate at the PVDF side of the interphase and propagate via a chain-pullout mechanism characteristic of semi-interpenetrating polymer networks involving thermoplastic materials.journal article153 249 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Mineralization of iron oxide by ferritin homopolymers immobilized on SiO2 nanoparticles(2018-10-25); ; ; ; The iron storage protein ferritin is well known for its ability to mineralize iron oxides in its interior cavity. In this study, the authors investigated the mineralization behavior of H and L ferritin homopolymers assembled from individual subunits. The authors’ approach included molecular dynamics simulations, which suggested that ferritin subunits arrange themselves on silica surfaces with the active side facing away from the interface, although non covalent adsorption interactions might be weak. In experimental studies, the nucleation of iron oxide nuclei could be observed at ferritin homopolymers which were covalently immobilized through the EDC/NHS strategy at the surface of silica nanoparticles. Mineralization was initiated by the addition of ammonium iron (II) sulfate hexahydrate ((NH4)2Fe(SO4)2·6H2O) as the source of iron ions and trimethylamine N-oxide as the oxidant. The results demonstrate that immobilized H and L ferritin homopolymers on silica surfaces are able to induce the formation of a cohesive thin film of magnetic iron oxide crystals (magnetite and/or maghemite).journal article90 71 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Physisorption of α-chymotrypsin on SiO2 and TiO2: A comparative study via experiments and molecular dynamics simulations(2016-01-13); ; ; ; In order to understand fundamental interactions at the interface between immobilized enzymes and ceramic supports, the authors compare the adsorption features of chymotrypsin on SiO2 and TiO2 colloidal particles by means of a combination of adsorption experiments and molecular dynamics simulations. While the dependency of the adsorption amount on pH is consistent with the trend predicted the Derjaguin-Landau-Verwey-Overbeek theory, other effects can only be rationalized if the atomic-scale details of the water-mediated protein-surface interactions are considered. On both surfaces, a clear driving force for the formation of a double monolayer at the saturation coverage is found. Although nearly equal free energies of adsorption are estimated on the two materials via a Langmuir adsorption analysis, about 50% more proteins per unit of surface can be accommodated on TiO2 than on SiO2. This is probably due to the lower surface diffusion mobility of the adsorbed protein in the latter case. Surface anchoring is realized by a combination of direct ionic interactions between charged proteins and surface sites (more pronounced for SiO2) and distinct structuring of the surface hydration layers in which the contact residues are embedded (more pronounced for TiO2). Finally, normalization of the data with respect to particle surface areas accessible to the proteins, rather than determined by means of the Brunauer-Emmett-Teller nitrogen adsorption isotherm, is crucial for a correct interpretation of the results.journal article169 123 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of divalent versus monovalent cations on the MS2 retention capacity of amino-functionalized ceramic filters(Royal Society of Chemistry, 2018-04-10); ; ; ; Ceramic capillary membranes conditioned for virus filtration via functionalization with n-(3-trimethoxysilylpropyl)diethylenetriamine (TPDA) are analyzed with respect to their virus retention capacity when using feed solutions based on monovalent and divalent salts (NaCl, MgCl2). The log reduction value (LRV) by operating in dead-end mode using the model bacteriophage MS2 with a diameter of 25 nm and an IEP of 3.9 is as high as 9.6 when using feeds containing MgCl2. In contrast, a lesser LRV of 6.4 is observed for feed solutions based on NaCl. The TPDA functionalized surface is simulated at the atomistic scale using explicit-solvent molecular dynamics in the presence of either Na+ or Mg2+ ions. Computational prediction of the binding free energy reveals that the Mg2+ ions remain preferentially adsorbed at the surface, whereas Na+ ions form a weakly bound dissolved ionic layer. The charge shielding between surface and amino groups by the adsorbed Mg2+ ions leads to an upright orientation of the TPDA molecules as opposed to a more tilted orientation in the presence of Na+ ions. The resulting better accessibility of the TPDA molecules is very likely responsible for the enhanced virus retention capacity using a feed solution with Mg2+ ions.journal articleBand:20Heft:16121 100 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Mathematical aspects of catalyst positioning in lithium/air batteries(IOP Publishing, 2020-02-25); ; ; In this paper we investigate a system of partial differential equations describing the clogging process of non-aqueous lithium/air batteries. The main aim is to optimize the positioning of catalysts on the surface of the pore of the battery in order to maximize the efficiency of the battery. To this end we analyze the parameter-to-state map which maps the initial catalyst positions cat0(x) to the diminishing radius of the pore until clogging. We obtain results on the continuity and Fréchet differentiability of the parameter-to-state map and we obtain the related sensitivity system. The paper also includes numerical experiments, which compare a greedy approach to catalyst positioning with results obtained by an analytic optimisation procedure.journal articleBand:36Heft:423 20