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Ice-nucleating organisms play important roles in the environment. With their ability to induce ice formation at temperatures just below the ice melting point, bacteria such as Pseudomonas syringae attack plants through frost damage using specialized ice-nucleating proteins. Besides the impact on agriculture and microbial ecology, airborne P. syringae can affect atmospheric glaciation processes, with consequences for cloud evolution, precipitation, and climate. Biogenic ice nucleation is also relevant for artificial snow production and for biomimetic materials for controlled interfacial freezing. We use interface-specific sum frequency generation (SFG) spectroscopy to show that hydrogen bonding at the water-bacteria contact imposes structural ordering on the adjacent water network. Experimental SFG data and molecular dynamics simulations demonstrate that ice-active sites within P. syringae feature unique hydrophilic-hydrophobic patterns to enhance ice nucleation. The freezing transition is further facilitated by the highly effective removal of latent heat from the nucleation site, as apparent from time-resolved SFG spectroscopy.
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http://dx.doi.org/10.1126/sciadv.1501630 | DOI Listing |
ACS Appl Mater Interfaces
September 2025
Department of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
Cyclic peptides (CPs) are versatile building blocks whose conformational constraints foster ordered supramolecular architectures with potential in biomedicine, nanoelectronics, and catalysis. Herein, we report the development of biomimetic antifreeze materials by conjugating CPs bearing ice-binding residues to 4-arm polyethylene glycol (PEG) via click chemistry. The concentration-dependent self-assembly of these CP-PEG conjugates induces programmable morphological transitions, forming nanotube networks above the critical aggregation concentration (CAC) and two-dimensional nanosheet networks near the CAC.
View Article and Find Full Text PDFJ Chem Phys
September 2025
Dipartimento di Fisica, Università degli Studi di Roma La Sapienza, Piazzale Aldo Moro 5, Rome 00185, Italy.
The equilibration dynamics of ultrastable glasses subjected to heating protocols has attracted recent experimental and theoretical interest. With simulations of the mW water model, we investigate the devitrification and "melting" dynamics of both conventional quenched (QG) and vapor deposited (DG) amorphous ices under controlled heating ramps. By developing an algorithm to reconstruct hydrogen-bond networks, we show that bond ring statistics correlate with the structural stability of the glasses and allow tracking crystalline and liquid clusters during devitrification and melting.
View Article and Find Full Text PDFNanoscale
September 2025
School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China.
Metal matrix composites are widely employed in aerospace and marine engineering due to their excellent mechanical properties and chemical stability. However, their surfaces remain vulnerable to corrosion, icing, and mechanical wear, severely compromising long-term reliability in harsh environments. Inspired by natural superhydrophobic surfaces such as lotus leaves, functional interfaces with high water repellency and interfacial stability can be engineered through the synergistic design of hierarchical micro/nanostructures and low-surface-energy chemical modifications.
View Article and Find Full Text PDFJ Therm Biol
August 2025
Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada; Innovation and Portfolio Management, Canadian Blood Services, Edmonton, AB, Canada. Electronic address:
Extreme temperature fluctuations during routine handling and shipping of cryopreserved cell products significantly compromise product quality in ways that extend beyond the duration and peak temperature of the fluctuation. The type of cryoprotectant used and the initial ice nucleation temperature influence ice crystal growth during rewarming events, in turn impacting cell survival. Using a cryomicroscope together with temperature profiles recorded in cord-blood units, ice crystal growth was tracked through five transient-warming events (TWEs) that peaked at -30 °C, -20 °C, or -10 °C.
View Article and Find Full Text PDFCryobiology
September 2025
UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry, School of Science and Technology, NOVA University Lisbon, Caparica, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, School of Science and Technology, NOVA University Lisbon, Caparica, Portugal. Electroni
High-throughput experimental screening is desirable to minimize data acquisition time from vast workloads. Cell cryopreservation experiments are routinely performed in single-sample cryovials despite cell seeding being performed in 96-well microplates because these substrates are known to induce microliter supercooling, are prone to thermal compressibility and their lengthy preparation period extends cell exposure time to potentially cytotoxic cryoprotectants. Rather than improving the methodological preciseness of cooling, latest efforts have focused on refining cryoprotectant formulations and supplement precautionary ice nucleators.
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