https://www.um.edu.mt/library/oar/handle/123456789/403 2026-09-24T13:30:44Z https://www.um.edu.mt/library/oar/handle/123456789/149273 Title: Spectrophotometric studies of a fluorescent naphthalenediimide PET and ICT pH indicator and DNA intercalator Authors: Johnson, Alex D.; Valentino, Mario; Hunter, Gary J.; Magri, David C. Abstract: Three naphthalenedimides (NDIs) were studied by UV-visible absorbance, fluorescence and circular dichroism spectroscopy in aqueous methanolic solution as DNA intercalators. Distinct solution colours are observed for the compounds under room lighting and upon irradiation with 365 nm UV light. The tetra-substituted dimethylaminoethylene NDI is designed as a fluorescent pH indicator with a ‘fluorophore–spacer–receptor’ construct based on a photoinduced electron transfer (PET) mechanism. This NDI derivative exhibits a significant change in the ellipticity with calf-thymus DNA. Fluorescence DNA titrations further revealed strong binding towards DNA, resulting in pronounced emission quenching. Incubation of MCF-7 cells reveals localisation of the fluorescent probe in the nucleus, specifically in the nucleoli. 2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/149272 Title: Alkylpiperazino-1,8-Naphthalimide fluorescent probes for exploring micellar membrane nanospaces Authors: Bazalieieva, Yelyzaveta; Magri, David C. Abstract: Two 4-piperazine-1,8-naphthalimides were designed as fluorescent probes for exploring the local polarity and proton concentration at the interface of micelles. Designed with an 𝘢𝘯𝘤𝘩𝘰𝘳₁-𝘧𝘭𝘶𝘰𝘳𝘰𝘱𝘩𝘰𝘳𝘦-𝘴𝘱𝘢𝘤𝘦𝘳-𝘳𝘦𝘤𝘦𝘱𝘵𝘰𝘳-𝘢𝘯𝘤𝘩𝘰𝘳₂ layout, the hydrophobicity of the pH probes was tuned by substitution of the anchor modules with different alkyl chains (methyl, butyl and octyl) to facilitate the micellar penetration depth. Fluorescence switching ‘on’ in methanol/water media upon protonation of the piperazine receptor is driven by a competition between solvent polarity and photoinduced charge transfer. The solvatochromic properties were investigated to enhance visual naked-eye communication. The fluorescent probes were tasked with reporting on the local polarity and proton content within sodium dodecyl sulphate (SDS), cetyltrimethylammonium chloride (CTAC) and Triton X-100 micelles. The dimethyl-substituted probe reported on the environment about the micelle/bulk water interface. The more hydrophobic octyl-butyl-substituted probe explored deeper into the micelles. Insight was gained into the local polarity and proton gradients inside micelles, as corroborated by emission wavelength, fluorescence quantum yield and Δp𝘒ₐ values. The findings are discussed in the context of the benzofurazan polarity–Δp𝘒ₐ maps reported by Uchiyama and de Silva. 2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/149078 Title: A novel chemical-based approach to produce flexible polyurethane foams with negative Poisson’s ratios Abstract: This work and its abstract are both under embargo until the restriction is lifted. Description: Ph.D.(Melit.) 2022-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/148966 Title: Jellyfish bioactive compounds fueling marine biotechnology in blue economy and biomedicine Authors: La Spina, Enrico; Barbagallo, Ignazio A.; Giallongo, Cesarina; Longhitano, Lucia; Leotta, Paola; Conti, Giuseppe N.; Giallongo, Sebastiano; Lombardo, Sofia P.; Felici, Alberto; Bellia, Francesco; Tropea, Emanuela; Li Volti, Giovanni; Torrisi, Alfio; Marrone, Alessio; Deidun, Alan; Tiralongo, Francesco; Tibullo, Daniele Abstract: Jellyfish, often primarily perceived by the public as a marine nuisance, represent an increasingly valuable and sustainable source of diverse biomolecules with significant potential for the biomedical sciences, in addition to their crucial ecological role within marine ecosystems. This review explores the properties, extraction and applications of key jellyfish-derived compounds, including collagen, peptides, sulfated polysaccharides, glycoproteins and venom components. The relevance of jellyfish as a bioresource is underscored by episodic bloom events in the Mediterranean, where species such as Rhizostoma pulmo (Macri, 1778) have been reported in affected coastal areas. This review provides a critical synthesis of current advances in the extraction, characterization, and biotechnological exploitation of jellyfish-derived bioactive compounds, on ecologically and biotechnologically relevant Mediterranean species, which collectively represent accessible and high-impact targets for marine bioprospecting. Evidence from non-Mediterranean species is also discussed for comparative purposes to contextualize conserved biochemical features across different biogeographical regions. Among jellyfish-derived biomolecules, collagen emerges as the most technologically mature and translationally advanced compound, supported by reproducible extraction protocols, preserved triple-helical structure, cytocompatibility, and compatibility with pre-GMP manufacturing workflows. Recent studies further demonstrate that aquaculture-reared Cassiopea andromeda (Forsskål, 1775) may achieve collagen yields comparable to wild populations (~40–46%) while exhibiting enhanced antioxidant profiles, supporting the feasibility of controlled biofactory approaches. In contrast, peptides, sulfated polysaccharides, and venom components display promising biological activities but remain at earlier stages of technological readiness, requiring further standardization, structure–function elucidation, and regulatory development. Within circular and blue bioeconomy frameworks, jellyfish biomass—particularly from invasive or bloom-forming species such as C. andromeda—offers a concrete opportunity to unlock novel therapeutic solutions and advanced biomaterials, addressing critical unmet medical needs and offering a sustainable alternative to traditional biomedical resources. 2026-01-01T00:00:00Z