Search Results (8)

Thermoplastic polyimides (TPIs) are promising lightweight materials for replacing metal components in aerospace, rocketry, and automotive industries. Key TPI attributes include low density, thermal stability, mechanical strength, inherent flame retardancy, and intrinsic fluorescence under UV light. The application of advanced manufacturing techniques, especially 3D printing, could significantly broaden the use of TPIs; however, challenges in melt-processing this class of polymer represent a barrier. This study explored the processability, 3D-printing and hence mechanical, and fluorescence properties of TPI coupons, demonstrating their suitability for advanced 3D-printing applications. Moreover, the study successfully 3D-printed a functional impeller for an overhead stirrer, effectively replacing its metallic counterpart. Defects were shown to be readily detectable under UV light. A thorough analysis of TPI processing examining its rheological, morphological, and thermal properties is presented. Extruded TPI filaments were 3D-printed into test coupons with different infill geometries to examine the effect of tool path on mechanical performance. The fluorescence properties of the 3D-printed TPI coupons were evaluated to highlight their potential to produce intricately shaped thermally stable, fluorescence-based sensors. Full article

Nanoparticles show great promise as a platform for developing vaccines for the prevention of infectious disease. We have been investigating a method whereby nanocapsules can be formulated from protein, such that the final capsules contain only the cross-linked protein itself. Such nanocapsules are made using a silica templating system and can be customised in terms of size and porosity. Here we compare the construction and characteristics of nanocapsules from four different proteins: one a model protein (ovalbumin) and three from infectious disease pathogens, namely the influenza virus, Helicobacter pylori and HIV. Two of the nanocapsules were assessed further. We confirm that nanocapsules constructed from the urease A subunit of H. pylori can reduce subsequent infection in a vaccinated mouse model. Further, we show that capsules constructed from the HIV gp120 protein can be taken up by dendritic cells in tissue culture and can be recognised by antibodies raised against the virus. These results point to the utility of this method in constructing protein-only nanocapsules from proteins of varying sizes and isoelectric points. Full article

Using removable silica templates, protein nanocapsules comprising the A subunit of Helicobacter pylori urease (UreA) were synthesised. The templates were of two sizes, with solid core mesoporous shell (SC/MS) silica templates giving rise to nanocapsules of average diameter 510 nm and mesoporous (MS) silica templates giving rise to nanocapsules of average diameter 47 nm. Both were shown to be highly monodispersed and relatively homogenous in structure. Various combinations of the nanocapsules in formulation were assessed as vaccines in a mouse model of H. pylori infection. Immune responses were evaluated and protective efficacy assessed. It was demonstrated that vaccination of mice with the larger nanocapsules combined with an adjuvant was able to significantly reduce colonisation. Full article

Melanoma, an aggressive form of skin cancer, can be fatal if not diagnosed and treated early. Melanoma is widely recognized to resist advanced cancer treatments, including immune checkpoint inhibitors, kinase inhibitors, and chemotherapy. Numerous studies have shown that various Cannabis sativa extracts exhibit potential anticancer effects against different types of tumours both in vitro and in vivo. This study is the first to report that PHEC-66, a Cannabis sativa extract, displays antiproliferative effects against MM418-C1, MM329 and MM96L melanoma cells. Although these findings suggest that PHEC-66 has promising potential as a pharmacotherapeutic agent for melanoma treatment, further research is necessary to evaluate its safety, efficacy, and clinical applications. Full article

Momordica cochinchinensis is a herbal medicine used throughout Asia and this study investigated the antimelanoma potentials and molecular mechanisms of M. cochinchinensis seed with emphasis on extraction to optimise bioactivity. Overall, the aqueous extract was superior, with a wider diversity and higher concentration of proteins and peptides that was more cytotoxic to the melanoma cells than other extraction solvents. The IC50 of the aqueous extract on melanoma cells were similar to treatment with current anticancer drugs, vemurafenib and cisplatin. This cytotoxicity was cancer-specific with lower cytotoxic effects on HaCaT epidermal keratinocytes. Cytotoxicity correlated with MAPK signalling pathways leading to apoptosis and necrosis induced by triggering tumour necrosis factor receptor-1 (TNFR1), reducing the expression of nuclear factor kappa B (NF-kB), and suppression of BRAF/MEK. This efficacy of M. cochinchinensis seed extracts on melanoma cells provides a platform for future clinical trials as potent adjunctive therapy for metastatic melanoma. Full article

There is a growing demand for better delivery systems to improve the stability and efficacy of DNA vaccines. Here we report the synthesis of a non-viral DNA vaccine delivery system using a novel adjuvanted solid lipid nanoparticle (SLN-A) platform as a carrier for a DNA vaccine candidate encoding the Urease alpha (UreA) antigen from Helicobacter pylori. Cationic SLN-A particles containing monophosphoryl lipid A (adjuvant) were synthesised by a modified solvent-emulsification method and were investigated for their morphology, zeta potential and in vitro transfection capacity. Particles were found to bind plasmid DNA to form lipoplexes, which were characterised by electron microscopy, dynamic light scattering and fluorescence microscopy. Cellular uptake studies confirmed particle uptake within 3 h, and intracellular localisation within endosomal compartments. In vitro studies further confirmed the ability of SLN-A particles to stimulate expression of pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) in human macrophage-like Tohoku Hospital Pediatrics-1 (THP-1) cells. Lipoplexes were found to be biocompatible and could be efficiently transfected in murine immune cells for expression of recombinant H. pylori antigen Urease A, demonstrating their potential as a DNA vaccine delivery system. Full article

The Cedecea genus is comprised of six rarely isolated species within the Enterobacteriaceae family. Representatives are Gram-negative motile bacilli, and are typically oxidase-negative, lipase-positive and resistant to colistin and cephalothin. In this study, a putative novel Cedecea species (designated strain ZA_0188^T), isolated from the koala hindgut, was characterised using a polyphasic taxonomic approach. Maximum average nucleotide identity (ANI) and 16S ribosomal RNA (rRNA) similarity scores well below thresholds of species demarcation were reported, at 81.1% and 97.9%, respectively. Multilocus phylogenetic analysis indicated strain ZA_0188^T was most similar to but divergent from recognised Cedecea species. The isolate’s genomic G+C content was determined as 53.0 mol%, >1% lower than previously reported in Cedecea. Phenotypically, strain ZA_0188^T was distinct from recognised Cedecea species such as colistin- and cephalothin-sensitive, lipase-, sorbitol-, sucrose-, and Voges-Proskauer-negative, and melibiose-, arabinose-, arginine-, and rhamnose-positive. In preliminary experiments, strain ZA_0188^T exhibited cellulase activity and high-level tolerance to eucalyptus oil compared to other enteric species surveyed. Collectively, these findings suggest that strain ZA_0188^T represents a novel enteric species, for which the name Cedecea colo is proposed. Full article

High frequency (HF) electromagnetic fields (EMFs) have been widely used in many wireless communication devices, yet within the terahertz (THz) range, their effects on biological systems are poorly understood. In this study, electromagnetic radiation in the range of 0.3–19.5 × 10¹² Hz, generated using a synchrotron light source, was used to investigate the response of PC 12 neuron-like pheochromocytoma cells to THz irradiation. The PC 12 cells remained viable and physiologically healthy, as confirmed by a panel of biological assays; however, exposure to THz radiation for 10 min at 25.2 ± 0.4 °C was sufficient to induce a temporary increase in their cell membrane permeability. High-resolution transmission electron microscopy (TEM) confirmed cell membrane permeabilization via visualisation of the translocation of silica nanospheres (d = 23.5 ± 0.2 nm) and their clusters (d = 63 nm) into the PC 12 cells. Analysis of scanning electron microscopy (SEM) micrographs revealed the formation of atypically large (up to 1 µm) blebs on the surface of PC 12 cells when exposed to THz radiation. Long-term analysis showed no substantial differences in metabolic activity between the PC 12 cells exposed to THz radiation and untreated cells; however, a higher population of the THz-treated PC 12 cells responded to the nerve growth factor (NGF) by extending longer neurites (up to 0–20 µm) compared to the untreated PC12 cells (up to 20 µm). These findings present implications for the development of nanoparticle-mediated drug delivery and gene therapy strategies since THz irradiation can promote nanoparticle uptake by cells without causing apoptosis, necrosis or physiological damage, as well as provide a deeper fundamental insight into the biological effects of environmental exposure of cells to electromagnetic radiation of super high frequencies. Full article