David Henry

Three solvent extraction methods (Soxhlet, sonication, and accelerated solvent extraction (ASE)) were investigated to develop an efficient technique for isolating and quantifying water repellency-inducing compounds (saturated long-chain (≥ C14) carboxylic acids, alkanes, alcohols, and sterols) from soils. The Soxhlet method was the most efficient at removing organic material from a deep yellow sand under dryland agriculture and grey sand under an Eucalyptus plantation. Although the sonication and ASE methods are time-efficient and facilitate high sample throughput, they were less effective for organic extraction (8.6% and 2.9% for dryland agriculture, 14.0% and 8.9% for plantation). While a range of chemical species from each of the four classes of soil water repellency-inducing compounds were extracted by the three methods, differences in the efficacies of the techniques were identified. Soxhlet extraction consistently recovered greater amounts of carboxylic acids, alcohols, and steroids, whereas ASE removed the largest amount of alkane. However, compounds from all classes were only identified from Soxhlet extracts of both field soils. The results indicate care is needed when comparing concentrations of compounds reported from extractions of water repellent soils using different extraction techniques.

PARK7 mRNA encodes DJ-1 protein, which functions as a protective agent against oxidative stress and cell damage within the brain cells. Mutations in the mRNA can lead to reduced production of DJ-1 and initiate brain diseases such as Parkinson’s disease. Transport of appropriate mRNA to damaged brain cells may provide a suitable treatment. Mesoporous silica nanoparticles (MSNPs), particularly pore-expanded and dye-labeled varieties, are regarded as potential carriers for large therapeutic agents such as mRNA. This study explored the influence of alterations in reaction conditions on the structural characteristics of MSNPs to produce nanoparticles with favorable characteristics for delivering large therapeutic agents to target sites. One-stage and two-stage procedures were compared for the introduction of 3-aminopropyltriethoxysilane (APTES) and APTES-dye adduct, in conjunction with two different surfactants, cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC). Analysis of the MSNPs shows that the two-stage method using CTAB as a surfactant produced amine-functionalized, dye-labelled particles with smaller overall size and better uniformity than the one-stage approach. However, due to their small pore size (<10 nm), these particles were unable to encapsulate the PARK7 mRNA (926 nucleotides). The one-stage method via CTAC produced MSNPs with large (150 nm), broad pore distribution (10–20 nm), and high aggregation, limiting their suitability for brain-targeted gene delivery. In comparison, the two-stage method using CTAC yielded well-ordered MSNPs with an optimal size (80 nm) and pore diameters (15–20 nm), enabling effective encapsulation of the large PARK7 mRNA and offering strong potential for future brain gene therapy studies.

Soil water repellency (SWR) is a major agro-ecological soil management issue caused by hydrophobic organic compounds that hinder soil water absorption and affect soil function. Recent modelling studies indicate that climate change will increase the severity of SWR, compounding these effects. This study investigated the effects of climatic and soil factors on SWR in surface (0–10 cm) soils from 355 sites under uniform land-use across an area of 60,000 km2 in south-western Australia, a region with a Mediterranean climate. There were marked gradients in temperature (mean minimum temperature (Meanmin, 7.7–12.2 °C), mean maximum temperature (Meanmax, 19.0–22.9 °C), rainfall (507–1443 mm/year) and pan evaporation (Evap, 1169–1772 mm/year) across the sites. SWR was measured in the laboratory on oven dried samples using the ethanol droplet test. Boosted regression tree analysis showed that 10 soil variables explained 78 % of the variance in SWR, with clay, silt and OC contents the main contributors. Incorporating the four climatic variables explained 84 % of the variance of SWR, with Meanmax the major contributing factor. Thus, while soil properties dominated the expression of SWR, climate had a secondary impact. Meanmax however, was inversely related to SWR, suggesting that rising temperatures due to climate change could result in a reduction in SWR. Furthermore, given the strong relationship between SWR and OC content, climate mitigation projects aimed at enhancing soil OC storage may inadvertently increase the expression and severity of SWR. Recognition of this should be included in soil carbon mitigation project protocols.

In recent years, there has been a significant increase in antibacterial resistance, leading to a decline in the effectiveness of antibiotic drugs. This situation underscores the urgent need to explore suitable alternatives to antibiotics. To address this global challenge, it is crucial to understand new approaches, including their mechanisms, advantages, and limitations, which can help in the design of effective substitutes for antibiotics. Extensive research in this field has yielded notable progress. This review article aims to summarize innovative strategies for combating antibacterial resistance, such as metal-organic frameworks (MOFs), metal nanoparticles, photodynamic therapy (PDT), and antibacterial peptides. Additionally, the article discusses examples of their effectiveness and applications. Further research has also focused on combining these methods to enhance their efficiency, with some relevant studies highlighted. It is hoped that in the future, these materials will serve as replacements for current drugs, ultimately resolving the issue of antibacterial resistance.

The increasing prevalence of healthcare-associated infections from multidrug-resistant bacteria presents a growing challenge due to their high transmissibility, and resistance to traditional antimicrobial strategies. In this study, we introduce an innovative dual-mode antibacterial strategy through the development of novel surface coatings on glass substrates, offering a proof-of-concept solution for enhanced infection control. Our approach uniquely combines the light-active methylene blue silane (MBS1) dye with the potent antimicrobial compound dimethyloctadecyl[3-(trimethoxysilyl)propyl] ammonium chloride (QAS) into silica nanoparticles (SNPs) to create multifunctional antibacterial surface coatings. The distinct use of silane-functionalized MB and QA enables strong covalent bonding with silica nanoparticles, while the robust silane chemistry ensures durable adhesion of SNPs to the glass substrates. While MBS1–SNP coatings generated highly hydrophilic (CA = 28°), light-active surfaces, combination of QAS (QA–MBS1–SNP) coating enhanced surface hydrophobicity (CA = 90°) without compromising photokilling efficiency. The antibacterial efficacy of these coatings was rigorously tested against the Gram-negative bacterium
Escherichia coli
. The synergistic action of MB and QA demonstrated exceptional photokilling performance achieving >99.999% (>5-log reduction) bactericidal activity under white light (∼500 lux, ∼0.0732 mW cm
−2
) and effectively inhibited biofilm formation by up to 80%. The demonstrated efficacy of these coatings highlights their potential for transformative applications in healthcare settings, providing a robust, multifaceted approach to infection control.

Polymer gel dosimeters have shown potential for clinical 3D dosimetry; however, their use has been limited due to low sensitivity and reliance on scarcely available magnetic resonance imaging. This study aimed to optimise a PASSAG (Poly AMPS Sodium Salt And Gelatin) polymer gel dosimeter for X-ray computed tomography, to enhance its clinical feasibility. The total monomer concentration was increased to improve sensitivity, and different cosolvents were tested to enhance the limited solubility of N, N'-methylenebisacrylamide, the crosslinker. n-propanol was identified as the optimal cosolvent, allowing for an 18.3% monomer concentration, 30% crosslinker to total comonomer mass gel, at a 3:7 cosolvent-to-water ratio. The optimised formulation, PASSAG-N (PASSAG- n-propanol), consisted of 54.4% w/w deionised water, 23.3% n-propanol, 12.8% 2-acrylamido-2-methylpropane sulfonic acid sodium salt, 5.5% N, N'-methylenebisacrylamide, 4.0% gelatin, and 0.089% (4.65mM) tetrakis (hydroxymethyl)phosphonium chloride. The dosimeter was irradiated within a standard timeframe to assess its sensitivity, and theoretical calculations confirmed its equivalence to water, soft tissue, brain, and muscle. Compared to a cosolvent-free formulation, PASSAG-N exhibited a 250% increase in Hounsfield unit (HU) change, demonstrating enhanced sensitivity. The optimised gel showed a linear response over a 1-12 Gy dose range, with an average sensitivity of 1.072 ± 0.041 HU Gy⁻¹ and a dose resolution ≤ 0.31 Gy, making it a promising alternative for clinical X-ray computed tomography-based dosimetry. This study highlights the potential of PASSAG-N as a highly sensitive and potentially practical polymer gel dosimeter for clinical applications.

Plastic pollution is a pressing global challenge, with current management strategies often falling short regarding environmental impacts. As an alternative to plastic waste management approaches, the Galleria mellonella (Greater wax moth) has emerged as a potential natural agent to reduce plastic waste through its biodegradation. The G. mellonella larvae have a unique ability to consume and biodegrade various polymeric materials, including plastics, making them an eco-friendly solution to plastic waste management. This review provides a comprehensive overview of the current status of G. mellonella larvae in waste bioconversion and future perspectives in plastic waste management. Key challenges of the application of G. mellonella include its use in large-scale waste processing, economic feasibility, and environmental impact. This review highlights the potential of G. mellonella as a sustainable solution for plastic waste management and its possible integration into biorefineries for the production of valuable materials.

Photodynamic therapy (PDT) is an emerging clinical modality for diverse disease conditions, including cancer. This technique involves, the generation of cytotoxic reactive oxygen species by a photosensitizer in the presence of light and oxygen. Methylene blue (MB) is a cationic dye with an ability to act as photosensitizing and bioimaging agent. The direct utilization of MB as photosensitizer for biological applications has often been impeded by its poor photostability and unwanted tissue interactions. Nanocarriers such as mesoporous silica nanoparticles (MSNs) provide an effective means of overcoming these limitations. However, the mere physical adsorption of the dye within the MSN can result in leakage, compromising the effectiveness of PDT. Therefore, in this work, we report the conjugation of MB into MSNs using novel MB-silane derivatives, namely MBS1 and MBS2, to create dye-doped and amine-functionalized MSNs (MBS1-AMSN and MBS2-AMSN). The PDT efficacy and bioimaging capability of these nanoparticles were compared with those of MSNs in which MB was non-covalently encapsulated (MB@AMSN). The synthesized nanoparticles, ultra-small in size (≤ 35 ± 4 nm) with monodispersity, exhibited enhanced fluorescence quantum yields. MBS1-AMSN demonstrated 70-fold increase, while MBS2-AMSN showed 33-fold improvement in fluorescence quantum yields compared to MB@AMSN at the same concentration. Covalent conjugation resulted in a 2-fold enhancement in the singlet oxygen quantum yield of the dye in MBS1-AMSN and 1.2-fold improvement in MBS2-AMSN, compared to non-covalent encapsulation. Assessment on RAW 264.7 macrophages revealed superior fluorescence in cell imaging for MBS1-AMSN, establishing it as a more efficient PDT agent compared to MBS2-AMSN and MB@AMSN. These findings suggest that MBS1-AMSN holds significant potential as a theranostic nanoplatform for image-guided PDT.
•A novel MB covalently encapsulated MSNs has developed in ultra-small size.•The nanocomposites showed high dye loading and negligible dye leakage.•Exhibited remarkable fluorescence and singlet oxygen quantum yields.•The nanocomposites demonstrated enhanced PDT efficacy in vitro.

3D printed electrode substrates with novel geometries may significantly improve the efficacy of photoelectrocatalysis for degradation of recalcitrant pollutants such as organophosphate flame retardants (OPFRs). However, the 3D printed substrates often have an irregular topology that can lead to a less uniform arrangement of nanotubes following anodisation. This study investigated the effect of polishing 3D-printed Ti substrates prior to anodisation to form TiO2 nanotube array electrodes, and their subsequent applicability for photoelectrocatalytic treatment of OPFRs in water matrices. Polished and non-polished electrodes exhibited differences in morphology in terms of average roughness, (0.38 and 3.10 µm, respectively), leading to more uniform TiO2 nanotubes of the former. Water contact angle measurements revealed the non-polished electrode was super-hydrophilic and the polished electrode hydrophilic (water contact angles of 6.4˚ and 16.1˚, respectively). Despite these differences, the polished and non-polished electrodes exhibited very similar electrochemical responses. In fact, the purity and electrical conductivity of water matrices affected the photoelectrocatalytic performance more than the electrode morphology. The purified water (PW) matrix facilitated the highest degradation/removal of OPFRs, compared to tap water matrices. In particular, individual OPFR degradation levels in PW were 74% ± 9, 37% ± 10, 33% ± 9, 31% ± 11 and 3% ± 5 for triphenyl phosphate, tris(butyl) phosphate, tris(isobutyl) phosphate, tris(2-butoxyethyl) phosphate and tris(2-chloroisopropyl) phosphate, respectively. The removal of OPFRs was relative to their reactivity to hydroxyl radicals, which was higher for the aryl then alkyl straight-chain and then chlorinated compounds. This study reveals that polishing of electrode substrates is not required for the preparation of effective photoelectrocatalytic reactors to treat recalcitrant pollutants (e.g. OPFRs), Importantly, future development of novel high-profile 3D printed electrode will not be hindered by the requirement to polish the substrates prior to anodisation.

Plastic pollution in terrestrial environments is a growing concern, with an increasing focus on the impact of plastic additives on soil ecosystems. We evaluated the impact of additives from conventional plastics (ACP) and biodegradable plastics (ABP) on the soil nematode, Pratylenchus neglectus. The additives represented five functional classes (antioxidants, colourants, flame retardants, nucleating agents, and plasticisers). P. neglectus exhibited concentration-dependent mortality when exposed to the additives, with Tartrazine, an ABP colourant, inducing higher mortality compared to the conventional counterpart. No significant changes in the locomotory patterns of P. neglectus were observed, whereas oxidative stress significantly increased in response to all assistive treatments. Exposure to most of the additives resulted in a significant decline in nematode reproduction; ACPs generally caused more severe effects than ABPs. Our findings highlight a complexity in how plastic additives impact soil organisms and challenge the assumption that ABPs may be universally safer for ecosystems. The study emphasises the importance of conducting ecotoxicological assessments of specific ABPs on important species to inform the design of environmentally sustainable plastics. The results also suggest that P. neglectus could serve as a valuable sentinel organism for evaluating the ecological impacts of plastic pollution in soil.