Antibiotic resistance has made the treatment of biofilm-related infections challenging. As such, the quest for next-generation antimicrobial technologies must focus on targeted therapies to which ...pathogenic bacteria cannot develop resistance. Stimuli-responsive therapies represent an alternative technological focus due to their capability of delivering targeted treatment. This study provides a proof-of-concept investigation into the use of magneto-responsive gallium-based liquid metal (LM) droplets as antibacterial materials, which can physically damage, disintegrate, and kill pathogens within a mature biofilm. Once exposed to a low-intensity rotating magnetic field, the LM droplets become physically actuated and transform their shape, developing sharp edges. When placed in contact with a bacterial biofilm, the movement of the particles resulting from the magnetic field, coupled with the presence of nanosharp edges, physically ruptures the bacterial cells and the dense biofilm matrix is broken down. The antibacterial efficacy of the magnetically activated LM particles was assessed against both Gram-positive and Gram-negative bacterial biofilms. After 90 min over 99% of both bacterial species became nonviable, and the destruction of the biofilms was observed. These results will impact the design of next-generation, LM-based biofilm treatments.
The direct conversion of CO2 to carbon is a highly providential route; however, conventional thermal and catalytic approaches are hindered by high energy demands and are limited by coking. Here, we ...report a robust and highly selective method for the direct conversion of CO2 to solid carbon over EGaIn liquid metal (LM) alloy. We utilized the low-melting point of this alloy to facilitate the reduction of CO2 at low temperatures, producing 319 μmol h−1 of carbon at 200 °C, and remarkably enabling CO2 activation and carbon production even at room temperature, without the use of a supplementary reductant such as hydrogen. The deployed LM showed no signs of deactivation by coking and the generated carbon is shown to naturally accumulate at the top of the LM where it can be easily collected. In situ XPS measurements indicate an increase of 9.6% in the carbon–carbon bond content and an equivalent decrease in the Ga metal content, upon exposure of the LM to CO2 for 30 mins at 200 °C and 1 bar. This led to the conclusion that solid carbon and gallium oxide are the final reaction products of this process. Density functional theory calculations shed further light on the adsorption and dissociation of CO2 over Ga and EGaIn. The presented method creates a pathway to transforming CO2 to perpetually stored solid carbon and can therefore set a trajectory for making a measurable impact on carbon intensive industries.
Abstract
A major health concern of the 21
st
century is the rise of multi-drug resistant pathogenic microbial species. Recent technological advancements have led to considerable opportunities for ...low-dimensional materials (LDMs) as potential next-generation antimicrobials. LDMs have demonstrated antimicrobial behaviour towards a variety of pathogenic bacterial and fungal cells, due to their unique physicochemical properties. This review provides a critical assessment of current LDMs that have exhibited antimicrobial behaviour and their mechanism of action. Future design considerations and constraints in deploying LDMs for antimicrobial applications are discussed. It is envisioned that this review will guide future design parameters for LDM-based antimicrobial applications.
The surfaces of liquid metals can serve as a platform to synthesise two-dimensional materials. By exploiting the self-limiting Cabrera-Mott oxidation reaction that takes place at the surface of ...liquid metals exposed to ambient air, an ultrathin oxide layer can be synthesised and isolated. Several synthesis approaches based on this phenomenon have been developed in recent years, resulting in a diverse family of functional 2D materials that covers a significant fraction of the periodic table. These straightforward and inherently scalable techniques may enable the fabrication of novel devices and thus harbour significant application potential. This review provides a brief introduction to liquid metals and their alloys, followed by detailed guidance on each developed synthesis technique, post-growth processing methods, integration processes, as well as potential applications of the developed materials.
Water is a unique solvent that is ubiquitous in biology and present in a variety of solutions, mixtures, and materials settings. It therefore forms the basis for all molecular dynamics simulations of ...biological phenomena, as well as for many chemical, industrial, and materials investigations. Over the years, many water models have been developed, and it remains a challenge to find a single water model that accurately reproduces all experimental properties of water simultaneously. Here, we report a comprehensive comparison of structural and dynamic properties of 30 commonly used 3-point, 4-point, 5-point, and polarizable water models simulated using consistent settings and analysis methods. For the properties of density, coordination number, surface tension, dielectric constant, self-diffusion coefficient, and solvation free energy of methane, models published within the past two decades consistently show better agreement with experimental values compared to models published earlier, albeit with some notable exceptions. However, no single model reproduced all experimental values exactly, highlighting the need to carefully choose a water model for a particular study, depending on the phenomena of interest. Finally, machine learning algorithms quantified the relationship between the water model force field parameters and the resulting bulk properties, providing insight into the parameter–property relationship and illustrating the challenges of developing a water model that can accurately reproduce all properties of water simultaneously.
Two-dimensional piezotronics will benefit from the emergence of new crystals featuring high piezoelectric coefficients. Gallium phosphate (GaPO
) is an archetypal piezoelectric material, which does ...not naturally crystallise in a stratified structure and hence cannot be exfoliated using conventional methods. Here, we report a low-temperature liquid metal-based two-dimensional printing and synthesis strategy to achieve this goal. We exfoliate and surface print the interfacial oxide layer of liquid gallium, followed by a vapour phase reaction. The method offers access to large-area, wide bandgap two-dimensional (2D) GaPO
nanosheets of unit cell thickness, while featuring lateral dimensions reaching centimetres. The unit cell thick nanosheets present a large effective out-of-plane piezoelectric coefficient of 7.5 ± 0.8 pm V
. The developed printing process is also suitable for the synthesis of free standing GaPO
nanosheets. The low temperature synthesis method is compatible with a variety of electronic device fabrication procedures, providing a route for the development of future 2D piezoelectric materials.
We report the synthesis of centimeter sized ultrathin GaN and InN. The synthesis relies on the ammonolysis of liquid metal derived two-dimensional (2D) oxide sheets that were squeeze-transferred onto ...desired substrates. Wurtzite GaN nanosheets featured typical thicknesses of 1.3 nm, an optical bandgap of 3.5 eV and a carrier mobility of 21.5 cm2 V–1 s–1, while the InN featured a thickness of 2.0 nm. The deposited nanosheets were highly crystalline, grew along the (001) direction and featured a thickness of only three unit cells. The method provides a scalable approach for the integration of 2D morphologies of industrially important semiconductors into emerging electronics and optical devices.
It is well-understood that during the liquid-to-solid phase transition of alloys, elements segregate in the bulk phase with the formation of microstructures. In contrast, we show here that in a Bi-Ga ...alloy system, highly ordered nanopatterns emerge preferentially at the alloy surfaces during solidification. We observed a variety of transition, hybrid and crystal-defect-like patterns, in addition to lamellar and rod-like structures. Combining experiments and molecular dynamics simulations, we investigated the influence of the superficial Bi and Ga
O
layers during surface solidification and elucidated the pattern-formation mechanisms, which involve surface-catalysed heterogeneous nucleation. We further demonstrated the dynamic nature and robustness of the phenomenon under different solidification conditions and for various alloy systems. The surface patterns we observed enable high-spatial-resolution nanoscale-infrared and surface-enhanced Raman mapping, which reveal promising potential for surface- and nanoscale-based applications.
Fiber-optic gas sensors have been considered a low-cost, effective, and robust approach for monitoring nitrogen dioxide (NO2) gas which is a major toxic gaseous pollutant. The integration of ...functional nanoscale materials provides additional dimensions for realizing ultra-sensitive and selective NO2 detection, however, the trade-off is the need for sophisticated photonic structures or external non-optical peripherals (e.g. electrical heaters). In this work, we demonstrate the development of a room temperature, all-optical, and high-performance NO2 sensor based on a simple D-shaped optical fiber incorporated with ultra-thin two-dimensional (2D) tin disulfide (SnS2). A visible light source at 473 nm is used to power the optical fiber, and at the same time excite the 2D SnS2 layer via the evanescent field, to generate extra charge carriers. Upon exposure to NO2 at room temperature, the physisorbed gas molecules induce charge exchange with the 2D SnS2. This significantly re-distributes the photo-excited charge carriers in the ultra-thin material, therefore manipulating the corresponding optical absorption and scattering. As a result, the optical output power intensity varies as the sensor output through the evanescent field coupling. This all-optical sensor demonstrates an optical power variation of up to 7 µW upon the exposure of NO2 gas at a low concentration of 50 ppb. This response is fully reversible with an extremely low limit of detection (LOD) of 0.464 ppb. We consider that this work provides a feasible and simple solution to realize high-performance optical gas sensors without the integration of external non-optical peripherals for effective monitoring of environmentally hazardous gases.
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•A simple D-shaped optical fiber incorporates 2D SnS2 without extra peripherals.•Low-power visible light excites charge carriers in the SnS2 via evanescent field.•The physisorbed gas molecules change optical absorption and scattering in 2D SnS2.•All-optical NO2 sensor with an ultralow limit of detection at room temperature.
Biosensors are essential components for effective healthcare management. Since biological processes occur on molecular scales, nanomaterials and nanosensors intrinsically provide the most appropriate ...landscapes for developing biosensors. Low-dimensional materials have the advantage of offering high surface areas, increased reactivity and unique physicochemical properties for efficient and selective biosensing. So far, nanomaterials and nanodevices have offered significant prospects for glucose sensing. Targeted glucose biosensing using such low-dimensional materials enables much more effective monitoring of blood glucose levels, thus providing significantly better predictive diabetes diagnostics and management. In this review, recent advances in using low dimensional materials for sensing glucose are summarized. Sensing fundamentals are discussed, as well as invasive, minimally-invasive and non-invasive sensing methods. The effects of morphological characteristics and size-dependent properties of low dimensional materials are explored for glucose sensing, and the key performance parameters such as selectivity, stability and sensitivity are also discussed. Finally, the challenges and future opportunities that low dimensional materials can offer for glucose sensing are outlined.
Biosensors are essential components for effective healthcare management.
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