Nanoscience News (<front>)

Biomimetic Isotropic Omnidirectional Intelligent Strain Sensor

Inspired by human fingerprints, an isotropic omnidirectional strain sensor in a heterogeneous skin-compatible soft substrate is proposed. The design as an involute of a circle structure achieves hypersensitivity and enables intelligent direction discrimination ability for applications in healthcare, soft robotics and more. More details can be found in article number 2420322 by Muzi Xu, Luigi G. Occhipinti and co-workers.

Phase Transformation of Titanium Diselenide Devices

In article number 2418557, Wen-Wei Wu, and co-workers systematically investigate the phase transformation of titanium diselenide devices using in-situ transmission electron microscopy. Their study reveals a bias-induced phase transformation driven by titanium self-intercalation, transitioning from hexagonal TiSe2 to the orthorhombic Ti9Se2 conducting phase. These findings offer valuable insights into the structural and electronic dynamics of 1T-TiSe2, highlighting its potential for future applications in charge-density-waves-based devices.

Light-Driven Artificial Cell Micromotors

Light-driven artificial cell-based micromotors (Vesical@MoS2-ATPase) are developed for the treatment of degenerative osteoarthritis. The motors combined with ATPase can be directed to the inflammation site under light conditions and continuously release ATP for repairing damaged chondrocytes. More details can be found in article number 2416349 by Fei Peng, Yingfeng Tu, and co-workers.

Light-Driven Micromachines with Motion Transfer in 3D

In article number 2417742, Shuailong Zhang, Jiafang Li, and co-workers present light-driven multi-component micromachines that facilitate 3D motion transfer across different planes. These micromachines, fabricated using standard photolithography combined with direct laser writing, are assembled and actuated via programmable light patterns within an optoelectronic tweezers system. Utilizing charge-induced repulsion and dielectrophoretic levitation effects, the micromachines enable highly efficient mechanical rotation and effective inter-component motion transfer in three dimensions.

Abstract not available

• Speaker: Yining Chen (LSE)
• Friday 13 June 2025, 14:00-15:00
• Venue: MR12, Centre for Mathematical Sciences.
• Series: Statistics; organiser: Qingyuan Zhao.

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Abstract not available

• Speaker: Yuansi Chen (ETH Zurich)
• Friday 06 June 2025, 14:00-15:00
• Venue: MR12, Centre for Mathematical Sciences.
• Series: Statistics; organiser: Qingyuan Zhao.

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The weak interlayer coupling suppresses the recombination of photogenerated electron and hole, facilitating charge separation. The optimized PY-CN-BIP-Ni achieves 553.3 µmol g⁻¹ h⁻¹ CO production (94% selectivity), eightfold faster than its isomer with strong interlayer interactions under visible light.

Covalent organic frameworks (COFs) have emerged as promising photocatalysts owing to their structural diversity, tunable bandgaps, and exceptional light-harvesting capabilities. While previous studies primarily focus on developing narrow-bandgap COFs for broad-spectrum solar energy utilization, the critical role of interlayer coupling in regulating charge transfer dynamics remains unclear. Conventional monolayer-based theoretical models inadequately address interlayer effects that potentially hindering intralayer electron transport to catalytic active sites. This work employs density functional theory (DFT) calculations to investigate the influence of interlayer interactions on intralayer charge transfer in imine-based COFs. Theoretical analyses reveal that bilayer architectures exhibit pronounced interlayer interference in intramolecular charge transfer processes which has not been observed in monolayer models. Based on these mechanistic insights, this work designs two isomeric pyrene-based COFs incorporating identical electron donor (pyrene) and acceptor (nickel bipyridine) units but with distinct interlayer coupling strengths. Strikingly, the optimized COF with weakened interlayer interactions demonstrates exceptional photocatalytic CO2 reduction performance, achieving a CO evolution rate of 553.3 µmol g−1 h−1 with 94% selectivity under visible light irradiation without additional photosensitizers or co-catalysts. These findings establish interlayer engineering as a crucial design principle for developing high-performance COF-based photocatalysts for solar energy conversion applications.

Abstract not available

• Speaker: Kosuke Imai (Harvard University)
• Friday 16 May 2025, 14:00-15:00
• Venue: MR12, Centre for Mathematical Sciences.
• Series: Statistics; organiser: Qingyuan Zhao.

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Equivariance can enhance the data efficiency of machine learning models by incorporating prior knowledge about a problem. Thanks to their flexibility and generality, steerable CNNs are a popular design choice for equivariant networks. By leveraging concepts from harmonic analysis, these networks model symmetries through specific constraints on their learnable weights or filters. This framework facilitates the practical implementation of a wide variety of equivariant architectures – e.g. to most Euclidean isometries, including E(3), E(2) and their subgroups.

However, unknown or imperfect symmetries can sometimes lead to overconstrained weights and suboptimal performance. This challenge motivated the study of strategies to enforce softer priors into the models. In the second half of this talk, we will discuss a novel probabilistic approach to learning the degrees of equivariance in steerable CNNs. The method replaces the equivariance constraint on the weights with an expectation over a learnable distribution, which is analytically computed by leveraging its Fourier decomposition.

Link to join virtually: https://cam-ac-uk.zoom.us/j/87421957265

This talk is being recorded. If you do not wish to be seen in the recording, please avoid sitting in the front three rows of seats in the lecture theatre. Any questions asked will also be included in the recording. The recording will be made available on the Department’s webpage

• Speaker: Dr Gabriele Cesa - Qualcomm AI Research, Amsterdam
• Wednesday 28 May 2025, 15:05-15:55
• Venue: Lecture Theatre 1, Computer Laboratory, William Gates Building.
• Series: Wednesday Seminars - Department of Computer Science and Technology ; organiser: Ben Karniely.

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Iliana graduated from the University of Thessaloniki in 2017. After undertaking 4 internships and spending a couple of years in first opinion practice, she decided to pursue her dream of becoming a veterinary anaesthesiologist. She started her residency at the University of Cambridge in 2023.

Chaired by Muriel Dresen and Olivier Restif

• Speaker: Iliana Antonopoulou , Department of Veterinary Medicine
• Friday 02 May 2025, 08:45-10:00
• Venue: LT2.
• Series: Friday Morning Seminars, Dept of Veterinary Medicine; organiser: Fiona Roby.

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Piezoelectric materials with high piezoelectric coefficient (d 33) and high mechanical quality factor (Q m) are critical for advanced high-power applications. However, achieving this combination is challenging due to the inherent trade-off between d 33 and Q m. This work reports a novel strategy involving the introduction of defect dipoles into quadruple point compositions to break the conventional trade-off and simultaneously enhance d 33 to 710 pC/N and Q m to 929 in designed lead-free piezoelectric materials.

Piezoelectric materials with a high piezoelectric coefficient (d 33) and high mechanical quality factor (Q m) are vital for advanced high-power applications. However, achieving this combination is challenging, particularly for lead-free piezoelectrics, because a high d 33 value relies on mobile domain walls, which increase dissipative losses and reduce Q m. In this study, this longstanding trade-off is overcome by introducing defect dipoles (via Mn doping) into the quadruple point (QP) composition of the lead-free Ba(Sn, Ti)O3 system. The resultant 0.5%Mn-doped Ba(Sn0.11Ti0.89)O3 (BST-0.5%Mn) ceramic exhibits a high d 33 value of 710 pC/N and high Q m value of 929, while the BST-1%Mn ceramic achieves a d 33 value of 614 pC/N and Q m value of 1138. These values represent a 10-fold increase in Q m and 1.6-fold increase in d 33 for BST-0.5%Mn, compared to those for undoped BST. High-resolution scanning transmission electron microscopy and phase-field simulations reveal that the enhanced d 33 and Q m are attributable to the coexistence of multiple phases of QPs with symmetry-conforming defect dipoles, challenging the long-held notion of physical incompatibility between high d 33 and high Q m. These findings offer a pathway for designing eco-friendly piezoelectric materials with unprecedented performance, paving the way for sustainable and efficient high-power applications.

A hybrid lipoplex (RMC/pApoE2) composed of guanidine-rich lipids (metformin-inspired MLS and arginine-contained RLS), oleic acid-modified cerium dioxide (OA@CeO2), and pApoE2 restores neuron-microglia crosstalk to eliminate Aβ deposits from temporal and spatial multidimensions. It induces neuronal and microglial autophagy at the upstream and downstream of Aβ metabolism, along with enhanced pApoE2 transfection for intra- and extra-cellular elimination of Aβ aggregates.

Efficient clearance of amyloid-β (Aβ) is vital but challenging in Alzheimer's disease (AD) treatment due to its complicated regulation mechanisms during generation and metabolism. It necessitates a multidimensional synergistic strategy based on ingenious delivery system design. Herein, guanidine-rich lipids (metformin-inspired MLS and arginine-contained RLS) are devised to trigger selective chaperone-mediated autophagy for amyloid precursor protein degradation in neurons. They are further co-assembled with oleic acid-modified cerium dioxide (OA@CeO2) to form RMC assembly for pApoE2 delivery (RMC/pApoE2 lipoplex). The OA@CeO2 boosts macro-autophagy, alleviates oxidative stress and inflammatory microenvironment, and promotes the neurons-microglia crosstalk for Aβ elimination. Concurrently, both guanidine-rich lipids and OA@CeO2 benefit pApoE2 transfection in neurons, enabling the transport of Aβ into microglia, and facilitating enzymatic hydrolysis and cellular digestion of extracellular Aβ. The lipoplex-boosted neuron–microglia interactions ultimately eliminate both intra- and extra-cellular Aβ aggregates. Consequently, the RMC/pApoE2 lipoplex eliminates ≈86.9% of Aβ plaques in the hippocampus of APP/PS1 mice and restored the synaptic function and neuronal connectivity. Moreover, it recovers the spatial memory of APP/PS1 mice to nearly the level of WT control. The presented hybrid lipoplex showcases an advanced gene delivery system, and offers a promising strategy for Aβ clearance in AD treatment.

A self-organized nanocomposite addresses the challenge of energy storage materials degrading at high temperatures. The nanocomposite maintains exceptional performance from room temperature to 200 °C, with enhanced energy density and efficiency. Through the trirelaxor matrix and nanointerface with antiferroelectric nanoparticles, it offers a promising strategy for high-temperature dielectric energy storage, overcoming polarization and breakdown degradation at elevated temperatures.

A fundamental paradox in energy storage dielectrics lies in the challenge of achieving superior performance consistently across both room and elevated temperatures. This is addressed by designing a self-organized nanocomposite (1−x)(Ba,Sr)(Ti,Sn)O3-xBi1.5ZnNb1.5O7 composed of nano-sized antiferroelectric(AFE) particles embedded into a trirelaxor(TRE) matrix through nanoscale phase separation process. The optimal composition at x = 0.11 exhibits outstanding energy storage performance from room temperature (energy density = 8.5 J cm−3, efficiency = 94.8%, and figure of merit of 167 J cm−3) up to 200 °C (energy density = 4.85 J cm−3, efficiency >90% and figure of merit of 49 J cm−3), outperforming existing Pb-free dielectrics. High-resolution transmission electron microscopy and synchrotron x-ray diffractometry reveal that the coexisting nanometric antiferroelectric particles and the trirelaxor nanodomains sustain over a wide temperature range. Piezoresponse force microscopy and phase-field simulation show that hysteresis-free switching of trirelaxor nanodomains enables enhanced polarization and low hysteretic loss. Resistivity shows a 2–3 order of magnitude increases accompanying significant increase in breakdown strength up to high temperatures, attributable to deep charge trapping effect at high-density TRE/AFE interfaces as evidenced by thermally stimulated depolarization current. These favorable effects in the nano-composite are responsible for its high energy storage performance up to high temperatures.

A cost-effective symmetric PbSe-based device constructed from seven pairs of Pb0.988Cu0.002Se (p-type) and Pb1.02Cu0.002Se (n-type), which demonstrates impressive cooling temperature difference (ΔT C) of 32.8, 36.9, and 41.0 K with the hot side maintained at 303, 323, and 343 K, respectively.

Thermoelectric cooling technology has broad applications but is limited by the high cost of tellurium (Te) in commercially available Bi2Te3-based thermoelectric materials. Herein, a cost-effective symmetric PbSe-based device constructed from 7 pairs of Pb0.988Cu0.002Se (p-type) and Pb1.02Cu0.002Se (n-type) is presented, which demonstrates impressive cooling temperature difference (ΔT C) of 32.8 and 41.0 K with the hot side maintained at 303 and 343 K, respectively. This low-cost symmetric PbSe-based device exhibits superior cost-effectiveness (ΔT/cost) for near-room-temperature thermoelectric cooling compared to other Bi2Te3-based devices. Its high cooling performance primarily stems from an advanced carrier and phonon transport properties in p-type Pb0.988Cu0.002Se. Specifically, Pb vacancy and Cu substitution in Pb0.988Cu0.002Se act as strong p-type dopants that effectively optimize carrier density, resulting in a maximum power factor of 28.69 µW cm−1 K−2 at room temperature. Moreover, the mobile Cu atoms within the lattice significantly impede phonon propagation, leading to a low room-temperature lattice thermal conductivity of 1.10 W m−1 K−1. Finally, the room-temperature figure of merit (ZT) and average ZT value in p-type Pb0.988Cu0.002Se can reach 0.6 and 0.68 at 300–573 K, surpassing previous p-type PbSe-based polycrystals. This work emphasizes the significant potential of a cost-effective PbSe compound for near-room-temperature cooling applications.

An atomically ordered, spin-polarized Co-doped PdCu intermetallic compound is rationally synthesized. The introduction of spin-polarized Co atoms can enhance the *NO binding and hydrogenation on its N-side to form *HNO, which further produces *NH2OH. The subsequent coupling of *CO and *NH2OH leads to the efficient and stable formation of urea.

The electrocatalytic conversion of NO3 − and CO2 into urea features a potential means of reducing carbon footprint and generating value-added chemicals. Nonetheless, due to the limited efficiency of carbon−nitrogen (C─N) coupling and the competing side reaction that forms ammonia, the urea selectivity and production yield have remained low. In this work, a spin−polarized cobalt−doped, atomically ordered PdCu intermetallic compound (denoted as PdCuCo) is developed as an efficient urea electrosynthesis catalyst. The Pd and Cu serve as the adsorption sites for CO2 and NO3 −, respectively, and the spin−polarized Co sites promote the adsorption of *NO intermediate, followed by hydrogenation of *NO at its N−terminal to form *HNO, instead of at its O−terminal. The difference in the hydrogenation position switches the subsequent reaction pathway to produce urea, in contrast to the PdCu or Ni−doped PdCu intermetallic compounds with main product selectivity of ammonia. The PdCuCo electrocatalyst exhibited an outstanding electrosynthesis of urea from NO3 − and CO2, including a Faradaic efficiency of 81%, a high urea yield of 227 mmol gcat. −1 h−1, and a notable electrochemical stability of >260 h, suggesting the attractive potential of designing spin−polarized catalytic sites for carbon−nitrogen coupling processes.

Novel guidance conduits are fabricated through electrospinning and masked coaxial electrospraying, integrating topological, haptotactic, and chemotactic cues to promote cell migration, neural stem cell differentiation, and axonal extension. In rat models, these conduits inhibited fibroblast proliferation, preserved microglial homeostasis, and promoted neuronal regeneration, significantly improving functional recovery and offering a promising strategy for spinal cord injury treatment.

Spinal cord injury (SCI) is a debilitating condition that leads to severe disabilities and imposes significant economic and social burdens. Current therapeutic strategies primarily focus on symptom management, with limited success in promoting full neurological recovery. In response to this challenge, the design of novel guidance conduits incorporating multiple gradient cues, inspired is reported by biological processes, to enhance spinal cord repair. These conduits are fabricated using electrospinning and masked coaxial electrospraying, a simple yet effective method that integrates topological, haptotactic, and chemotactic cues into a single scaffold. The synergy of these cues significantly promoted cell migration, neural stem cell differentiation into neurons, and axonal extension, resulting in substantial improvements in spinal cord regeneration and functional recovery in a rat model. Single-nucleus RNA sequencing further demonstrated that the guidance conduit inhibited fibroblast proliferation, preserved microglial homeostasis, restored cellular proportions, and facilitated the regeneration of neuronal axons, dendrites, and synapses. This work presents an innovative, versatile platform for fabricating tissue scaffolds that integrate multiple gradient cues, offering a promising strategy for SCI treatment and broader tissue regeneration applications.

This research, highlighting i) the hierarchical assembly of Photonins, ii) the sugar–lectin binding which modulates structural stability and mechanical properties of sea silk, and iii) the use of golden sea silk as a photonic protein fiber.

The harvesting of sea silk, a luxurious golden textile traditionally obtained from the endangered mollusk Pinna nobilis, faces severe limitations due to conservation efforts, driving the search for sustainable alternatives. Atrina pectinata, a phylogenetically close relative within the Pinnidae family is identified, as a viable source of biomimetic sea silk. The byssal threads of A. pectinata can be processed using existing methods, providing a way to continue producing this historically significant textile. These threads exhibit a remarkable hierarchical structure with globular proteins organized across multiple scales and stabilized by supramolecular sugar-lectin interactions that influence their mechanical properties. Moreover, the threads display a brilliant golden hue arising from structural coloration, ensuring exceptional lightfastness, retaining their color for millennia. This discovery elucidates the biomolecular foundations of sea silk's unique properties and establishes A. pectinata as a sustainable candidate for producing exquisite golden textiles and bioinspired pigments, thereby addressing the growing demand for eco-friendly and long-lasting colored materials in the textile and pigment industries.

Achieving synergistic strengthening and toughening of natural fiber-reinforced composites remains a significant challenge. Drawing inspiration from multi-layer helical structures observed in natural organisms, a green, facile, and versatile transitional unit design strategy is designed to construct a gradual helical structure. This approach helps successfully achieve simultaneous strengthening and toughening of natural fiber-reinforced composites.

Multilayered helical arrangements are commonly observed in natural creatures to enhance their strength and toughness. A biomimicry of such an intricate structure has thus far been challenging. Herein, a green, facile, and versatile design strategy is proposed for transitional units. The proposed strategy is applied to develop a gradual helical (GH) structure that can reinforce thermoplastics using bamboo fibers (≈20 cm). A transitional unit is constructed through a combination of rolling and twisting. Following hot pressing, a biomimetic fiber-reinforced composite with a GH structure is fabricated. The GH structure is made up of 3D helical fibers with a gradual variation in the helical angle from the surface to the core, achieving minimal staggered angles and bridging of different fiber layers. Owing to stress decomposition and transfer as well as the coupling effect of the helical fibers, the GH structure exhibits outstanding tensile and bending strengths. Moreover, owing to the staggered arrangement, bridging, and deformation behavior of the fibers, the GH structure achieves remarkable impact toughness through crack deflection and fiber uncoiling. The GH structure and transitional unit assembly strategy can facilitate the development of advanced composites with superior mechanical properties through an environmentally friendly, simple, and versatile structural design approach.

This work introduces an efficient dual-directional upcycling scheme enabled through a mechanical homogenization pretreatment. It enables various layered oxide cathodes to be reprocessed into fresh NCM cathodes with tailored Ni contents through boosted atomic diffusion in just 4 h of solid-state sintering. Delivering upcycled cathodes with comparable electrochemical performances to their commercial counterparts, this approach excels itself from the cost-effectiveness over conventional acid-leaching resynthesis approaches.

Upcycling is regarded as a sustainable and promising recycling solution for spent lithium-ion batteries (LIBs). However, current upcycling strategies such as converting Ni-lean to Ni-rich cathodes struggle to change the composition of the spent cathodes to meet the diverse market demands. In addition, the commonly employed molten-salts method requires tens of hours of high-temperature treatment, restricting its sustainability. Herein, this study reports an efficient, flexible dual-directional upcycling strategy to upcycle a broad family of layered oxide cathodes into fresh LiNixCoyMnzO2 (NCM) cathodes with tailored Ni-contents—either increased or decreased—in just 4 h via mechanical homogenization pretreatment. This study confirms that the bulk diffusion of transition metals (TMs) is the rate-determining step in the resynthesis process, and the mechanical homogenization can shorten the diffusion pathway of TMs, thus reducing the sintering duration effectively. The as-upcycled NCM cathodes can deliver electrochemical performance on par with commercial counterparts. Notably, a systematic technoeconomic analysis shows that upcycling spent LiCoO2 into NCM622 can yield a profit up to 35 US$/kg, 30% higher than the conventional acid-leaching resynthesis approach. This work provides an energy-saving, widely adaptable, flexible, and cost-efficient method for regenerating spent cathode materials, paving the way for the sustainable recycling of LIBs.