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NanoManufacturing

Michael De Volder, Engineering Department - IfM
 

Recreating Silk's Fibrillar Nanostructure by Spinning Solubilized, Undegummed Silk

Dissolving Undegummed silk leads to a solution with undegraded silk that exhibits liquid-liquid phase separation (LLPS). Spinning the solution leads to fibers with a ≈20 nm nanofibrillar hierarchy that are 2.3 times tougher than natural silk fibers. This establishes the importance of retaining molecular weight, presence of sericins, and priming LLPS in designing tougher-than-nature fibers with fibrillar hierarchy.


Abstract

The remarkable toughness (>70 MJ m−3) of silkworm silk is largely attributed to its hierarchically arranged nanofibrillar nanostructure. Recreating such tough fibers through artificial spinning is often challenging, in part because degummed, dissolved silk is drastically different to the unspun native feedstock found in the spinning gland. The present work demonstrates a method to dissolve silk without degumming to produce a solution containing undegraded fibroin and sericin. This solution exhibits liquid-liquid phase separation above 10% (wt/wt), a behavior observed in the silk gland but not in degummed silk solutions to date. This partitioning enhances the stability of the undegummed solution, delaying gelation two-fold compared with degummed silk at the same concentration. When spun under identical conditions, undegummed solutions produces fibers 8× stronger and 218× tougher than degummed silk feedstocks. Through ultrasonication, undegummed wet spun fibers are seen to possess hierarchical structure of densely packed ≈20 nm nanofibrils, similar to native silks, although completely absent from fibers wet-spun from degummed silk solutions. This work demonstrates that the preservation of molecular weight, presence of sericin and stimulation of liquid-liquid phase separation underpin a new pathway to recreate a hierarchical fiber with structures akin to native silk.

Lanmodulin‐Decorated Microbes for Efficient Lanthanide Recovery

Bio-scaffolded lanmodulin (LanM) on E. coli is developed as a simple, effective material for repeated capture and release of rare earth elements (REEs). Over 80% of four REE cations are captured, even in the presence of excess competitive ions. The material can be employed in a filtration flow-through system with a capture capacity of 11.8 ± 0.9 mg g−1 dry cell weight.


Abstract

Rare earth elements (REEs) are essential for many clean energy technologies. Yet, they are a limited resource currently obtained through carbon-intensive mining. Here, bio-scaffolded proteins serve as simple, effective materials for the recovery of REEs. Surface expression of the protein lanmodulin (LanM) on E. coli, followed by freeze-drying of the microbes, yields a displayed protein material for REE recovery. Four REE cations (Y3+, La3+, Gd3+, and Tb3+) are captured efficiently, with over 80% recovery even in the presence of competitive ions at one-hundred-fold excess. Moreover, these materials are readily integrated into a filter with high capture capacity (12 mg g−1 dry cell weight) for the selective isolation and recovery of REEs from complex matrices. Further, the proteins in the filter remain stable over ten bind-and-release cycles and a week of storage. To improve the deployability of this filter material, a simple colorimetric assay with the dye alizarin-3-methyliminodiacetic acid is incorporated. The assay can be performed in under 5 min, enabling rapid monitoring of REE recovery and filter efficiency. Overall, this low-cost, robust material will enable environmentally friendly recycling and recovery of critical elements.

Perovskite‐Based Smart Eyeglasses as Noncontact Human–Computer Interaction

Smart eyeglasses based on perovskite photodetectors are developed, capable of directly converting visual stimuli from the reflected light of the eyeballs into electrical signals. After scaling up the pretraining data and model size, these eyeglasses achieve noncontact monitoring of eyeball movement with a 5° recognition angle, enabling unobtrusive control of a model car to execute 9 commands with 99.86% accuracy.


Abstract

More than 70% of human information comes from vision. The eye is one of the most attractive sensing sites to collect biological parameters. However, it is urgent to develop a cost-effective and easy-to-use approach to monitor eyeball information in a minimally invasive way instead of current smart contact lenses or camera-based eyeglasses. Here, the biomimetic mineralization strategy is developed to prepare large-grained perovskite film on the glass with prepared ITO electrodes, which displays the on–off ratio close to 300 times at 500 Lux light intensity, and the responsiveness reaches 22.09 A W−1. The smart eyeglasses composed of perovskite-based photodetectors can directly convert the visual stimuli from the reflective light of eyeballs into electrical signals in all light circumstances. After scaling up the pretraining data and the model size, the smart eyeglasses achieve the noncontact monitoring of the eyeball movement with the recognition angle of 5°, which can be used to unobtrusively drive the model car with great freedom. The smart eyeglasses based on the perovskite photodetectors provide cost-effective approaches for monitoring eyeball movements, which will show great potential in the applications of man-machine control, augmented reality, individual healthcare, etc.

Surface Modification of 3D Biomimetic Shark Denticle Structures for Drag Reduction

Biomimetic shark denticles with alternating superhydrophobic and superhydrophilic regions are fabricated through 3D printing. Superhydrophobic and partially superhydrophobic denticles exhibit superior drag reduction performance compared to superhydrophilic ones by minimizing vortex formation, presenting a novel approach to the biomimetic design of shark denticles for optimal drag reduction.


Abstract

Shark skin features superhydrophilic and riblet-textured denticles that provide drag reduction, antifouling, and mechanical protection. The artificial riblet structures exhibit drag reduction capabilities in turbulent flow. However, the effects of the surface wettability of shark denticles and the cavity region underneath the denticle crown on drag reduction remain insufficiently explored. Here, 3D printing is utilized to fabricate realistic staggered and overlapped denticle arrays, modified to achieve superhydrophilic, superhydrophobic, and hybrid configurations, including external riblets hydrophilic/internal cavities hydrophobic (ELIB), and vice versa (EBIL). Denticles of varying heights are also fabricated. The results indicate that superhydrophobic, ELIB, and EBIL denticles outperform superhydrophilic ones in reducing drag, achieving a peak drag reduction rate of ≈20%. Notably, shorter denticles further improve drag reduction. Reduced vortex formation within the underneath cavity correlates with improved drag reduction. These vortices can function similarly to rolling bearings while facilitating momentum exchange and increasing skin friction drag. Superhydrophobic or partially superhydrophobic denticles (ELIBD/EBILD) mitigate this effect. This study suggests that sharks may secrete mucus on specific sections of their denticles to further reduce vorticity and drag, offering novel insights into the biomimetic design of shark denticles for optimized drag reduction.

Ultra‐Fast Moisture Sensor for Respiratory Cycle Monitoring and Non‐Contact Sensing Applications

Nanogap electrodes are combined with egg albumen to develop a fast and sensitive moisture sensor. This device integrates scalable manufacturing, exceptional sensitivity, rapid response times, and selective moisture detection across a 10–70% relative humidity range. The sensor is used for non-contact sensing applications and monitoring respiratory cycles in real-world settings.


Abstract

As human-machine interface hardware advances, better sensors are required to detect signals from different stimuli. Among numerous technologies, humidity sensors are critical for applications across different sectors, including environmental monitoring, food production, agriculture, and healthcare. Current humidity sensors rely on materials that absorb moisture, which can take some time to equilibrate with the surrounding environment, thus slowing their temporal response and limiting their applications. Here, this challenge is tackled by combining a nanogap electrode (NGE) architecture with chicked egg-derived albumen as the moisture-absorbing component. The sensors offer inexpensive manufacturing, high responsivity, ultra-fast response, and selectivity to humidity within a relative humidity range of 10–70% RH. Specifically, the egg albumen-based sensor showed negligible response to relevant interfering species and remained specific to water moisture with a room-temperature responsivity of 1.15 × 104. The nm-short interelectrode distance (circa 20 nm) of the NGE architecture enables fast temporal response, with rise/fall times of 10/28 ms, respectively, making the devices the fastest humidity sensors reported to date based on a biomaterial. By leveraging these features, non-contact moisture sensing and real-time respiratory cycle monitoring suitable for diagnosing chronic diseases such as sleep apnea, asthma, and pulmonary disease are demonstrated.

Phase‐Engineered Bi‐RuO2 Single‐Atom Alloy Oxide Boosting Oxygen Evolution Electrocatalysis in Proton Exchange Membrane Water Electrolyzer

A unique Bi-RuO2 single-atom alloy oxide is rational designed and achieved by phase engineering of the hexagonal close-packed RuBi single-atom alloy, to boost oxygen evolution electrocatalysis. The incorporation of Bi1 improves the activity by electronic density optimization and the stability by hindering surface Ru demetallation, enabling a practical proton exchange membrane water electrolyzer (PEMWE) that needs only 1.59 V to reach 1.0 A cm−2.


Abstract

Engineering nanomaterials at single-atomic sites can enable unprecedented catalytic properties for broad applications, yet it remains challenging to do so on RuO2-based electrocatalysts for proton exchange membrane water electrolyzer (PEMWE). Herein, the rational design and construction of Bi-RuO2 single-atom alloy oxide (SAAO) are presented to boost acidic oxygen evolution reaction (OER), via phase engineering a novel hexagonal close packed (hcp) RuBi single-atom alloy. This Bi-RuO2 SAAO electrocatalyst exhibits a low overpotential of 192 mV and superb stability over 650 h at 10 mA cm−2, enabling a practical PEMWE that needs only 1.59 V to reach 1.0 A cm−2 under industrial conditions. Operando differential electrochemical mass spectroscopy analysis, coupled with density functional theory studies, confirmed the adsorbate-evolving mechanism on Bi-RuO2 SAAO and that the incorporation of Bi1 improves the activity by electronic density optimization and the stability by hindering surface Ru demetallation. This work not only introduces a new strategy to fabricate high-performance electrocatalysts at atomic-level, but also demonstrates their potential use in industrial electrolyzers.

Super‐Resolution Goes Viral: T4 Virus Particles as Versatile 3D‐Bio‐NanoRulers

Various super-resolution fluorescence microscopy methods achieve nanoscale resolution, vital for visualizing subcellular structures. Choosing suitable biological standards is challenging, demanding precise geometry and specific labeling capabilities. Utilizing T4 bacteriophage as a 3D-Bio-NanoRuler is proposed. With DNA-PAINT and astigmatic imaging, detailed viral structures are revealed, offering a simple sample protocol and suggesting T4's potential as a benchmark in microscopy studies.


Abstract

In the burgeoning field of super-resolution fluorescence microscopy, significant efforts are being dedicated to expanding its applications into the 3D domain. Various methodologies have been developed that enable isotropic resolution at the nanometer scale, facilitating the visualization of 3D subcellular structures with unprecedented clarity. Central to this progress is the need for reliable 3D structures that are biologically compatible for validating resolution capabilities. Choosing the optimal standard poses a considerable challenge, necessitating, among other attributes, precisely defined geometry and the capability for specific labeling at sub-diffraction-limit distances. In this context, the use of the non-human-infecting virus, bacteriophage T4 is introduced as an effective and straightforward bio-ruler for 3D super-resolution imaging. Employing DNA point accumulation for imaging in nanoscale topography (DNA-PAINT) along with the technique of astigmatic imaging, the icosahedral capsid of the bacteriophage T4, measuring 120 nm in length and 86 nm in width, and its hollow viral tail is uncovered. This level of detail in light microscopy represents a significant advancement in T4 imaging. A simple protocol for the production and preparation of samples is further outlined. Moreover, the extensive potential of bacteriophage T4 as a multifaceted 3D bio-ruler, proposing its application as a novel benchmark for 3D super-resolution imaging in biological studies is explored.

Redistributing zinc-ion flux by work function chemistry toward stabilized and durable Zn metal batteries

http://feeds.rsc.org/rss/ee - Fri, 17/01/2025 - 05:39

Energy Environ. Sci., 2024, 17,2554-2565
DOI: 10.1039/D3EE04304E, PaperQiang Hu, Jisong Hu, Fei Ma, Yunbo Liu, Lincai Xu, Lei Li, Songtao Zhang, Xingquan Liu, Jingxin Zhao, Huan Pang
A multifunctional NbN-modified separator and an innovative work function chemistry strategy are designed to enhance the durability of ZMBs.
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Organic photovoltaics surpass the 20% efficiency milestone

http://feeds.nature.com/nmat/rss/current - Fri, 17/01/2025 - 00:00

Nature Materials, Published online: 17 January 2025; doi:10.1038/s41563-024-02076-8

Crystallization dynamics manipulation leads to vertically separated donor and acceptor phases in thick films, improving charge mobility and device efficiency.

Organic solar cells with 20.82% efficiency and high tolerance of active layer thickness through crystallization sequence manipulation

http://feeds.nature.com/nmat/rss/current - Fri, 17/01/2025 - 00:00

Nature Materials, Published online: 17 January 2025; doi:10.1038/s41563-024-02062-0

An organic regulator that can tune the crystallization sequence of active layer components has been described, achieving a certified efficiency of over 20% in single-junction organic solar cells, demonstrating remarkable tolerance for active layer thickness of 100–400 nm.

Stretch-induced endogenous electric fields drive directed collective cell migration in vivo

http://feeds.nature.com/nmat/rss/current - Fri, 17/01/2025 - 00:00

Nature Materials, Published online: 17 January 2025; doi:10.1038/s41563-024-02060-2

Electric fields guide collective cell migration in developing embryos of Xenopus laevis via a voltage-sensitive phosphatase.

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