arXiv subjects

Ido Braslavsky

Publications and source records attributed to Ido Braslavsky.

6 recordsLinked to original sources

arXiv2025

Biomimetic Engineering of a Fortified Ice Composite with Enhanced Mechanical Properties

This work presents BioPykrete, a new sustainable bio-composite material created from ice, nano-crystalline cellulose (CNC), and a tailor-made chimera protein designed to bind the two together. We developed and produced the chimera protein by linking AFPIII, an ice-binding protein, with CBM3a, a CNC-binding protein. As the suspension freezes, the CNC chains self-organize into a reinforcing network between the ice crystals. This structural enhancement limits crack propagation to typical pore sizes, allowing BioPykrete to avoid the brittle and sudden failure commonly associated with ice. Instead, it exhibits an elastic-like response to stress, making it suitable for construction and engineering applications. With compressive strength comparable with concrete, BioPykrete offers a sustainable and biodegradable alternative to construction materials suitable for the harsh arctic regions of the world where traditional methods are ineffective, and resources are scarce. Engineering chimera proteins with specific affinity to more than a single material type may help improve or tailor the properties of other composite materials.

q-bio.BM↗

arXiv2025

Kinetic roughening transition of ice crystals and its implications during recrystallization

Hypothesis Roughening transitions at solid-liquid interfaces govern crystal morphology in diverse systems. In ice crystallization, these transitions control interfacial faceting and surface kinetics. Faceted morphologies are often associated with ice-active molecules, which inhibit recrystallization and are essential for cryopreservation. We hypothesize that kinetic roughening transitions can induce faceting even in the absence of ice-active agents, particularly at high solute concentrations with depressed melting points, potentially complicating the interpretation of crystal morphology as an indicator of ice activity. Experiments We investigated the kinetic roughening transition of ice in dimethyl sulfoxide (DMSO) and proline-water solutions using cryomicroscopy and real-time image analysis. Crystals grew in microdroplets, maintaining near-equilibrium conditions as solute concentration increased during growth due to conversion of liquid water to ice. Antifreeze protein type III (AFPIII) was applied to distinguish intrinsic roughening from adsorption-mediated effects. Findings A distinct kinetic roughening transition temperature (TR = -16.0 +/- 0.2 oC) was identified, marking a shift from rounded disks at higher temperatures to faceted hexagonal plates at lower temperatures, independent of solute type. Recrystallization below TR revealed asymmetry between growth and melting interfaces. AFPIII promoted faceting even above TR, consistent with stabilization of step edges and elevation of the roughening transition temperature. These results clarify the interplay between intrinsic interface kinetics and molecular adsorption, with implications for interpreting ice morphology, surface roughening, and cryopreservation design.

cond-mat.mtrl-sci↗

arXiv2020

Heat flux balance description of unidirectional freezing and melting dynamics on a translational temperature gradient stage

Directional solidification occurs in industrial and natural processes, such as freeze-casting, metal processing, biological cryopreservation and freezing of soils. Translational temperature gradient stage allows to control the process of directional solidification and to visualise it with optical microscope. In this stage freezing velocity and temperature gradient are decoupled and are independently controlled. Here we study the dynamics of the phase transition interface in thin water samples using translational temperature gradient stage. We follow position of the ice-water interface with optical microscopy and compare it to solution of one dimensional Stefan problem in the low velocity limit. We find an agreement between experimental observations and theoretical predictions for constant velocity and during acceleration of the ice front. This work presents a practical framework for analysis and design of experiments on a translational temperature gradient stage.

physics.app-ph↗

arXiv2017

Particle Ice Front Interaction - The Brownian Ratchet Model

We treat the problem of particle pushing by growing ice as a free diffusion near a wall that moves with discrete steps. When the particle diffuse away from the surface the surface can grow, blocking the particle from going back. Elementary calculations of the model reproduce established results for the critical velocity $v_c$ for particle engulfment: $v_c\sim 1/r$ for large particles and $v_c\sim$ Const for small particles, $r$ being the particle's radius. Using our model we calculate the dragging distance of the particle by treating the pushing as a sequence of growing steps by the surface, each enabled by the particle's diffusion away. Eventually the particle is engulfed by ice growing around it when a rare event of long diffusion time away from the surface occurs. By calculating numerically the statistics of the diffusion times from the surface and therefore the probability for a such a rare event we calculate the total dragging time and distance $L$ of the particle by the ice front to be $L\sim\exp[1/(vr)]$ where $v$ is the freezing velocity. This relation for $L$ is confirmed by ours and others experiments. The distance $L$ provides a length scale for pattern formation during phase transition in colloidal suspensions, such as ice lenses and lamellae structures by freeze casting. Data from the literature for ice lenses thickness and lamellae spacing during freeze casting agree with our prediction for the relation of the distance $L$. These results lead us to conjecture that lamellae formation is dominated by their lateral growth which pushes and concentrates the particles between them.

cond-mat.soft↗

arXiv2012

Modeling the Influence of Antifreeze Proteins on Three-Dimensional Ice Crystal Melt Shapes using a Geometric Approach

The melting of pure axisymmetric ice crystals has been described previously by us within the framework of so-called geometric crystal growth. Nonequilibrium ice crystal shapes evolving in the presence of hyperactive antifreeze proteins (hypAFPs) are experimentally observed to assume ellipsoidal geometries ("lemon" or "rice" shapes). To analyze such shapes we harness the underlying symmetry of hexagonal ice Ih and extend two-dimensional geometric models to three-dimensions to reproduce the experimental dissolution process. The geometrical model developed will be useful as a quantitative test of the mechanisms of interaction between hypAFPs and ice.

physics.bio-ph↗

arXiv2012

Freezing and Melting Hysteresis Measurements in Solutions of Hyperactive Antifreeze Protein from an Antarctic Bacteria

Antifreeze proteins (AFPs) evolved in cold-adapted organisms and serve to protect them against freezing in cold conditions by arresting ice crystal growth. Recently, we have shown quantitatively that adsorption of AFPs not only prevents ice from growing but also from melting. This melting inhibition by AFPs, which results in superheated ice (Celik et al, PNAS 2010), is not a well-known phenomenon. Here we present our recent findings in which the Ca2+ - dependent hyperactive AFP from Marinomonas primoryensis (MpAFP) clearly displays this property. Additionally, we found that an ice crystal that is initially stabilized and protected by this type of AFP can be overgrown and then melted back to the original crystal. This repeatable process is likely due to melting inhibition, and supports the idea that AFPs bind irreversibly to ice surfaces.

cond-mat.soft↗