Nanoscience News (<front>)

Liquid crystal elastomer films with dense nanowire arrays exhibit synergistic adhesion and shape-changing properties. They curl toward the nanowire side under heat or chemical vapors but away from it with liquid droplets. Chemical modifications make them superoleophobic underwater, enabling precise droplet manipulation. This biomimetic design integrates enhanced adhesion with stimuli-responsive deformation, with promising applications in soft robotics and adaptive surfaces.

Abstract

Nature provides many examples of the benefits of nanoscopic surface structures in areas of adhesion and antifouling. Herein, the design, fabrication, and characterization of liquid crystal elastomer (LCE) films are presented with nanowire surface structures that exhibit tunable stimuli-responsive deformations and enhanced adhesion properties. The LCE films are shown to curl toward the side with the nanowires when stimulated by heat or organic solvent vapors. In contrast, when a droplet of the same solvent is placed on the film, it curls away from the nanowire side due to nanowire-induced capillary forces that cause unequal swelling. This characteristic curling deformation is shown to be reversible and can be optimized to match curved substrates, maximizing adhesive shear forces. By using chemical modification, the LCE nanowire films can be given underwater superoleophobicity, enabling oil repellency under a range of harsh conditions. This is combined with the nanowire-induced frictional asymmetry and the reversible shape deformation to create an underwater droplet mixing robot, capable of performing chemical reactions in aqueous environments. These findings demonstrate the potential of nanowire-augmented LCE films for advanced applications in soft robotics, adaptive adhesion, and easy chemical modification, with implications for designing responsive materials that integrate mechanical flexibility with surface functionality.

Uniform carbon nanodots (HNCDs) that inherit the single atomic Fe–N4 center of hemin while creating sp2-hybridized carbon surroundings were created by a simple solvothermal treatment of hemin. HNCDs synergistically modulated the energy level and electron transfer for converting the type II photodynamic process to type I, thus can significantly induce tumor pyroptosis and evoke strong antitumor immune response even under hypoxic environment.

Abstract

General synthesis and mechanical understanding of type I nano-photosensitizers are of great importance for hypoxia-resistant pyroptosis inducers. Herein, a simple solvothermal treatment is developed to convert non-photosensitive small molecules (hemin) into uniform carbon nanodots (HNCDs) with strong type I photodynamic activity and red fluorescence emission. These HNCDs inherit the single atomic Fe–N4 center of hemin while creating sp2-hybridized carbon surroundings, which synergistically modulated the energy level and electron transfer for converting the type II photodynamic process to type I. After encapsulating HNCDs with bovine serum albumin (BSA) to facilitate in vivo applications, the resulting BSA nanoparticles (HB) can image tumors and significantly induce the pyroptosis of tumor cells even under an extremely hypoxic environment (2% O2). This evokes a strong antitumor immune response, effectively restraining tumor growth and lung metastasis in triple-negative breast cancer mice, with good biocompatibility. This work introduces an applicable pyroptosis nano-inducer to combat hypoxic tumors and highlights the regulation of Fe–N4 centers to develop hypoxia-resistant type I nano-photosensitizers for cancer treatment.

The hardness of a polymer material greatly affects its applicability, but traditionally, increasing hardness tends to reduce toughness. This study introduces a hybrid soft segment strategy that effectively regulates the hardness of thermoplastic elastomers without compromising their inherent toughness, enhancing their safety and structural integrity for broader applications.

Abstract

The hardness of thermoplastic elastomers (TPEs) significantly influences their suitability for various applications, but traditionally, enhancing hardness reduces toughness. Herein a method is introduced that leverages hybrid soft segments to fine-tune the hardness of TPEs without compromising their exceptional toughness. Through the selective copolymerization of polytetramethylene ether glycols (PTMEGs) at various molecular weights, supramolecular poly(urethane-urea) TPEs are molecularly engineered to cover a wide spectrum of hardness while retaining good toughness. It is achieved through the formation of graded functional zones—densely packed for enhanced hardness and strength, and loosely packed for greater extensibility and toughness—driven by variations in PTMEG chain length and mismatched supramolecular interactions. Through the establishment and systematic investigation of a TPE library, the intricate interplay between design, structure, and performance of these materials is elucidated, refining the optimization techniques. The TPEs demonstrate exceptional mechanical properties, including a variant with a Shore hardness of 86A and a toughness of 819 MJ m−3, alongside a softer variant with a 59A hardness and a 786 MJ m−3 toughness. The innovation extends to a scalable solvent-based TPE production line, promising widespread industrial application. This advancement reimagines the potential of high-performance TPEs and composites, offering versatile materials for demanding applications.

This review provides a comprehensive overview of deactivation mechanisms and regeneration strategies for single-atom catalysts (SACs), identifying five deactivation pathways across seven destabilization scenarios and detailing three key regeneration strategies. It introduces advanced in situ and ex situ characterization techniques relevant to these processes. These insights provide valuable guidance for designing stable and efficient SACs for energy applications.

Abstract

Numerous in situ characterization studies have focused on revealing the catalytic mechanisms of single-atom catalysts (SACs), providing a theoretical basis for their rational design. Although research is relatively limited, the stability of SACs under long-term operating conditions is equally important and a prerequisite for their real-world energy applications, such as fuel cells and water electrolyzers. Recently, there has been a rise in in situ characterization studies on the destabilization and regeneration of SACs; however, timely and comprehensive summaries that provide the catalysis community with valuable insights and research directions are still lacking. This review summarizes recent advances in the destabilization mechanisms and regeneration strategies of SACs, specifically highlighting various state-of-the-art characterization techniques employed in the studies. The factors that induce destabilization in SACs are identified by discussing the failure of active sites, coordination environments, supports, and reaction conditions under long-term operating scenarios. Next, the primary regeneration strategies for SACs are introduced, including redispersion, surface poison desorption, and exposure of subsurface active sites. Additionally, the advantages and limitations of both in situ and ex situ characterization techniques are discussed. Finally, future research directions are proposed, aimed at constructing structure–stability relationships and guiding the design of more stable SACs.

Pickering emulsion is stabilized by biomineralized manganese nanoparticles and aluminum hydroxide, enabling rapid and efficient loading of AAVs, diversifying AAV endocytic pathways, and further activating the cGAS-STING pathway for higher AAV target gene expression and stronger cellular immune responses.

Abstract

Recombinant adeno-associated viruses (rAAVs) have emerged as promising vaccine vectors due to their enduring efficacy with a single dose. However, insufficient cellular immune responses and the random and non-specific distribution of AAVs post-injection may hinder the development of AAV vaccines. Here, a novel Pickering emulsion platform stabilized by biomineralized manganese nanoparticles and aluminum hydroxide, which can rapidly and efficiently load AAVs, is reported. This platform confers AAVs with favorable in vivo distribution kinetics, diversifying AAV endocytic pathways with reduced dependency on the sialic acid receptor-mediated route, and ultimately enhancing AAV infection efficiency in antigen present cells (APCs). Concurrently, the Pickering emulsion substantially boosts endogenous 2′3′-cGAMP production, further activating the cGAS-STING pathway for stronger immune responses and improving protective efficacy in bacterial infection models. The STING pathway activation also increases AAV target gene expression, potently augmenting the cross-protective potential of AAV vaccines for COVID-19. These synergistic effects ensure that effective immune responses are induced even at one-fifth of the AAV vaccination dose, while the Pickering emulsion further reduces the accumulation of AAV in the liver, thereby improving their safety. The findings highlight the potential of Pickering emulsions as valuable enhancers for viral vectors, providing insights for their broader clinical applicability.

Research on the flexible bio-inspired cognitive systems, classified into near- and in-sensor computing, is addressed. Fundamental aspects, including biological processes, required components, and the device types for each component, as well as applications for wearable systems, are discussed. Additionally, perspectives on future research directions for flexible neuromorphic electronics are provided.

Abstract

Flexible neuromorphic architectures that emulate biological cognitive systems hold great promise for smart wearable electronics. To realize neuro-inspired sensing and computing electronics, artificial sensory neurons that detect and process external stimuli must be integrated with central nervous systems capable of parallel computation. In near-sensor computing, synaptic devices, and sensors are used to emulate sensory neurons and receptors, respectively. In contrast, in in-sensor computing, a single multifunctional device serves as both the receptor and neuron. Bio-inspired cognitive systems efficiently detect and process stimuli through data structuring techniques, significantly reducing data volume and enabling the extension of neuromorphic applications to smart wearable systems. To construct wearable near- and in-sensor computing, it is crucial to develop artificial sensory neurons and central nervous synapses that replicate the biological functionalities. Additionally, the integrated systems must exhibit high mechanical flexibility and integration density. This review addresses research on flexible bio-inspired cognitive systems, classified into near- and in-sensor computing. It covers fundamental aspects, including biological cognitive processes, the required components, and the structures for each component, as well as applications for wearable smart systems. Finally, it offers perspectives on future research directions for flexible neuromorphic electronics in smart wearable systems connected to the next-generation Internet of Things.

An LD-Ptn photocatalyst comprising PtO2 clusters and ZnO is synthesized using ZnAl-LDH as precursor. Owing to small size of PtO2 clusters (≈1.30 nm), LD-Ptn is rich in PtO2/ZnO interfaces and delivers outstanding photocatalytic activity for propane direct dehydrogenation under UV irradiation. Pt at PtO2/ZnO interfaces act as sites for photogenerated hole concentration, thus activating propane C─H bonds for propylene synthesis.

Abstract

The direct dehydrogenation of alkanes to olefins under mild conditions is challenging due to the inert nature of alkyl C─H bonds. Herein, an efficient photocatalytic system is developed for propane direct dehydrogenation (PDH) to propylene, consisting of ≈1.30 nm sized PtO2 clusters immobilized on a layered double hydroxide -derived ZnO/Al2O3 support (LD-Ptn). Under UV excitation (365 nm), photogenerated holes in ZnO migrate to Pt sites at PtO2/ZnO interfaces, thereby activating and dissociating C─H bonds in propane. A propylene production rate of almost 1 mmol g−1 h−1 and a nearly 100% selectivity are achieved for the compositionally optimized LD-Ptn photocatalyst. Control experiments and density functional theory calculations further verify that the excellent photocatalytic PDH performance of LD-Ptn stems from synergism between ZnO semiconductor and the loaded Pt species. This work identifies a promising new route for direct production of olefins from alkanes.

Simply adding a nucleating agent N,N′-(1,4-phenyl)diisonicotinamide (PDA) to poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene (PBTTT-C14) precisely tunes its crystallization and maximizes structural order. The improved molecular packing reduces disorder and elevates charge mobility. With optimized doping, this polymer achieves remarkable electrical conductivity (up to 1968 S cm⁻¹) and a power factor ≈176 µW m−1 K−2, expanding possibilities for high-performance thermoelectrics.

Abstract

Controlling the microstructure of semiconducting polymers is critical for optimizing thermoelectric performance, yet remains challenging, requiring complex processing techniques like alignment. In this study, a straightforward strategy is introduced to enhance the thermoelectric properties of semi-crystalline polymer films by incorporating minimal amounts of nucleating agents, a method widely used in traditional polymer industries. By blending less than 1 wt% of N,N′-(1,4-phenyl)diisonicotinamide (PDA) into poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT-C14), controlled modulation of crystallization behavior is achieved, resulting in reduced structural disorder and enhanced charge carrier mobility. Systematic investigations reveal that an optimal PDA loading of 0.9 wt% increases the crystallization degree by 45% compared to pristine PBTTT-C14 films. Under these optimized conditions, the PDA-modified PBTTT-C14 films exhibit a maximum electrical conductivity of 1,894 S cm−1 and a maximum power factor of 176 µW m−1 K−2, showing improvements of 96% and 433%, respectively, over doped pristine PBTTT-C14 films. These gains are attributed to the synergistic effects of polymer chain extension and reduced grain boundary resistance, which collectively enhance charge transport efficiency. Additionally, ion exchange doping is found to maintain a high charge carrier concentration while preserving the crystallinity introduced by PDA, paving the way for advanced thermoelectric materials and next-generation polymer-based electronics.

Through-sapphire machining is integrated with superconducting quantum processors (QPUs) and qubits. High coherence of the qubits is demonstrated as well as low parameter spread. This machining integration provides a route to further scaling of QPUs on new materials such as tantalum that are typically deposited on sapphire substrates. In addition, the machining provides a route to through-sapphire-vias in superconducting circuits.

Abstract

A sapphire machining process integrated with intermediate-scale quantum processors is demonstrated. The process allows through-substrate electrical connections, necessary for low-frequency mode-mitigation, as well as signal-routing, which are vital as quantum computers scale in qubit number, and thus dimension. High-coherence qubits are required to build fault-tolerant quantum computers and so material choices are an important consideration when developing a qubit technology platform. Sapphire, as a low-loss dielectric substrate, has shown to support high-coherence qubits. In addition, recent advances in material choices such as tantalum and titanium-nitride, both deposited on a sapphire substrate, have demonstrated qubit lifetimes exceeding 0.3 ms. However, the lack of any process equivalent of deep-silicon etching to create through-substrate-vias in sapphire, or to inductively shunt large dies, has limited sapphire to small-scale processors, or necessitates the use of chiplet architecture. Here, a sapphire machining process that is compatible with high-coherence qubits is presented. This technique immediately provides a means to scale quantum processing units (QPUs) with integrated mode-mitigation, and provides a route toward the development of through-sapphire-vias, both of which allow the advantages of sapphire to be leveraged as well as facilitating the use of sapphire-compatible materials for large-scale QPUs.

This study presents an in situ, two-step self-assembled system that enhances both T1 and T2 MRI signals through intracellular cascade regulation of contrast agent size, enabling T1-T2 dual-modal MRI for tumor imaging. It explores the relationship between nanostructure size and MRI contrast, providing a new method for developing MRI contrast and multi-morphological nanomedicines at targeted sites for improved theranostics.

Abstract

Currently, there is no conclusive evidence indicating that in situ self-assembled Gd nanostructures of varying sizes demonstrate distinct T1 and T2 signal enhancement capabilities. Furthermore, it remains uncertain whether size adjustment can effectively achieve enhanced T1-T2 dual-modal MRI. To address these uncertainties, a two-step in situ self-assembly strategy is developed. This approach began with a small-sized nanoprobe, Gd-TCO-P, with a hydrodynamic diameter (dH) of 16 ± 3 nm. This nanoprobe underwent alkaline phosphatase (ALP) cleavage and self-assembled intracellularly into short nanofibers termed Gd-NFs (dH: 200 ± 51 nm). The subsequent introduction of tetrazine-tetrazine crosslinked these Gd-NFs, leading to the formation of larger two-stage dendritic nanofibers known as Gd-TS-NFs (dH: 4371 ± 236 nm). This process achieves size-dependent enhancement of both T1 and T2 signals, which is validated through both in vitro and in vivo experiments, enabling precise long-term imaging of ALP-overexpressing tumors. This study not only provides valuable insights into the relationship between the size of in situ formed Gd nanostructures and T1/T2 MRI contrast enhancement, but also suggests a promising strategy for clinical applications of T1-T2 dual-modal MRI.

Nature Materials, Published online: 20 January 2025; doi:10.1038/s41563-024-02064-y

Solid-state electrolyte reduction and Li dendrite growth limit the stability of all-solid-state Li metal batteries. Here the authors show that reductive electrophiles gain electrons and metal cations from metal–nucleophile materials on contact, allowing the electrochemical formation of a dense, electron-blocking film that improves the stability of both the anode and high-voltage cathode.

Nature Materials, Published online: 20 January 2025; doi:10.1038/s41563-024-02071-z

The authors report Bose–Einstein condensation of a two-magnon bound state in Na2BaNi(PO4)2. This should stimulate further work on these types of geometrically frustrated materials.

The hierarchy problem, UV/IR mixing, nonrenormalisation theorems and new approaches to naturalness

In this talk I review the hierarchy problem, and I will describe recent progress in understanding the additional constraints that UV/IR mixing places on a theory that may be giving hints as to how it can be solved. As an example that can be treated rigorously, I will consider the UV/IR mixing associated with modular invariance in closed strings, and show that this yields a novel set of supertrace constraints. These constraints are similar to the nonrenormalisation theorems of supersymmetry but they are applicable in full generality. I discuss the various phenomenological consequences that arise including the lack of any power law running, and the apparent UV fixed-point behaviour. The talk will be pedagogical.

• Speaker: Steven Abel (Durham U., IPPP)
• Friday 24 January 2025, 16:00-17:00
• Venue: MR19 (Potter Room, Pavilion B), CMS.
• Series: HEP phenomenology joint Cavendish-DAMTP seminar; organiser: Terry Generet.

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Detecting and Attributing Change in Climate and Complex Systems: Foundations, Green's Functions, and Nonlinear Fingerprints

Detection and attribution (D&A) studies are cornerstones of climate science, providing crucial evidence for policy decisions. Their goal is to link observed climate change patterns to anthropogenic and natural drivers via the optimal fingerprinting method (OFM). We show that response theory for nonequilibrium systems offers the physical and dynamical basis for OFM , including the concept of causality used for attribution. Our framework clarifies the method’s assumptions, advantages, and potential weaknesses. We use our theory to perform D&A for prototypical climate change experiments performed on an energy balance model and on a low-resolution coupled climate model. We also explain the underpinnings of degenerate fingerprinting, which offers early warning indicators for tipping points. Finally, we extend the OFM to the nonlinear response regime. Our analysis shows that OFM has broad applicability across diverse stochastic systems influenced by time-dependent forcings, with potential relevance to ecosystems, quantitative social sciences, and finance, among others.

Key References V. Lucarini and M. D. Chekroun, Detecting and Attributing Change in Climate and Complex Systems: Foundations, Green’s Functions, and Nonlinear Fingerprints, Phys. Rev. Lett. 133, 244201 (2024) https://doi.org/10.1103/PhysRevLett.133.244201 V. Lucarini and M. D. Chekroun, Theoretical tools for understanding the climate crisis from Hasselmann’s programme and beyond, Nat. Rev. Phys. 5, 744 (2023) https://doi.org/10.1038/s42254-023-00650-8

• Speaker: Valerio Lucarini (University of Leicester)
• Thursday 23 January 2025, 15:00-16:00
• Venue: Centre for Mathematical Sciences, MR14.
• Series: Applied and Computational Analysis; organiser: Matthew Colbrook.

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Protein self-assembly – understanding and controlling the machinery of life

Proteins are the active molecules of life. However, most proteins do not work on their own in health or disease; a key challenge, therefore, is understanding how these molecules interact with each other to give rise to function or malfunction. This talk will outline our efforts to discover, understand and use the basic principles that drive protein assembly into larger scale structures and phases. I will discuss how controlling transitions between such phases can help us ameliorate biological malfunction when it occurs in disease, and well as develop new classes of functional materials.

• Speaker: Professor Tuomas Knowles, Yusuf Hamied Department of Chemistry
• Monday 03 March 2025, 18:00-19:00
• Venue: Bristol-Myers Squibb Lecture Theatre, Department of Chemistry.
• Series: Cambridge Philosophical Society; organiser: Beverley Larner.

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Protein self-assembly – understanding and controlling the machinery of life

Proteins are the active molecules of life. However, most proteins do not work on their own in health or disease; a key challenge, therefore, is understanding how these molecules interact with each other to give rise to function or malfunction. This talk will outline our efforts to discover, understand and use the basic principles that drive protein assembly into larger scale structures and phases. I will discuss how controlling transitions between such phases can help us ameliorate biological malfunction when it occurs in disease, and well as develop new classes of functional materials.

• Speaker: Professor Tuomas Knowles, Yusuf Hamied Department of Chemistry
• Monday 03 March 2025, 18:00-19:00
• Venue: Bristol-Myers Squibb Lecture Theatre, Department of Chemistry.
• Series: Cambridge Philosophical Society; organiser: Beverley Larner.

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Positivity theorems for hyperplane arrangements via intersection theory

I will discuss three recent combinatorial theorems about hyperplane arrangements: the top-heavy conjecture, log concavity of the characteristic polynomial, and non-negativity of the Kazhdan-Lusztig polynomial. Each of these results is proved by studying the cohomology of a projective algebraic variety associated with the arrangement.

• Speaker: Nicholas Proudfoot, University of Oregon
• Wednesday 19 March 2025, 14:15-15:15
• Venue: CMS MR13.
• Series: Algebraic Geometry Seminar; organiser: Dhruv Ranganathan.

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