Publications

Abstract Catanionic mixtures, composed of cationic and anionic surfactants, spontaneously form robust self-assembled aggregates whose morphology, size, and surface charge can be tailored by adjusting the surfactant mixing ratio. This straightforward and scalable approach, based on easily obtainable components, offers a versatile and simple platform with high potential for drug delivery. However, developing viable nanocarriers also requires a favorable cytotoxicity profile, high drug loading, and strong bioactivity-features that catanionic vesicles often lack. Here, we present a systematic study of pH-sensitive catanionic vesicles composed of mixtures of the biocompatible, FDA-approved anionic surfactant sodium lauroyl sarcosinate (SLSar) and various cationic double-tailed surfactants (didodecyldimethylammonium bromide and bis-quat 12-s-12 gemini surfactants). The different vesicle systems form spontaneously at low critical aggregation concentrations (approximate to 3-30 mu mol kg-1), and exhibit a broad range of size distributions, high surface charge (positive and negative), and long-term colloidal stability. Cytotoxicity screening in healthy L929 fibroblasts enabled the selection of highly biocompatible compositions, with gemini/SLSar systems showing superior doxorubicin (DOX) encapsulation efficiency. These vesicles exhibit enhanced DOX release at acidic pH (approximate to 6.0), mimicking tumor microenvironments, and demonstrate rapid and efficient uptake in lung carcinoma cells within 30 min, increasing over 3 h. Remarkably, DOX-loaded vesicles achieve potent cytotoxicity at only 5 nM DOX-well below the IC50 of free drug-highlighting enhanced therapeutic efficacy and potential for reduced systemic toxicity. Overall, SLSar-based catanionic vesicles constitute a simple, stable, and tunable nanocarrier platform with significant potential for pH-responsive, low-dose cancer chemotherapy.

Abstract The efficient delivery of nucleic acids (NAs) remains a major challenge in gene therapy due to their poor stability and limited cellular uptake. Even though non-viral vectors have been pivotal to overcoming some of these challenges, significant barriers, such as intracellular digestion of NAs and limited endosomal escape, still remain. Here, we developed novel stimuli-responsive lipoplexes integrating a 2-hydroxychalcone-based cationic amphiphile (CnNCh, with 4 or 6 carbons in their alkyl chains, n = 4 or 6) and monoolein (MO). This combination leverages the photoisomerization and pH-sensitivity of chalcone derivatives, along with the fusogenic capabilities of MO, to achieve enhanced transfection efficiency via light irradiation. To reach this goal, we first assessed the cytotoxicity of the cationic amphiphiles in healthy and tumor cells. We then prepared mixtures with varying CnNCh/MO molar ratios, yielding net cationic vesicles with long-term colloidal stability. Subsequently, NAs were efficiently compacted into lipoplexes at N/P ratios (positively charged nitrogen/negatively charged phosphate) higher than 1, attaining near-complete compaction. Light and pH stimuli induce the formation of the expected products, but without compromising lipoplex stability or activating premature NA release. Vesicles with different CnNCh/MO molar ratios do not induce the loss of viability of normal fibroblasts for concentrations up to 50 mu M. Crucially, siRNA-lipoplex mixtures having C4NCh/MO molar ratios of 1/1 and 2/1 (N/P = 6) achieve significant GFP knockdown after irradiation, indicative of successful siRNA delivery and biological effects. Using biomimicking endosomal membranes, we show that photoactivation enhances membrane fusion, suggesting a mechanism entailing light-mediated endosomal escape. Our study provides proof-of-concept for a light-switch mechanism offering precise spatiotemporal control over gene silencing, a highly desirable feature in therapeutic applications.

Abstract BackgroundContinuing professional development (CPD) for primary school teachers is crucial to address conceptual and attitudinal challenges in science education. Chemistry, in particular, is often perceived as abstract and difficult to teach, which contributes to its underrepresentation in classroom practice.PurposeThis study investigates the perceptions and choices of Portuguese primary school teachers engaged in a CPD programme, with a focus on understanding the limited emphasis placed on Chemistry compared to other scientific disciplines.SampleThe study involved 108 Portuguese primary teachers who participated in a two-year CPD programme centred on experimental approaches to science teaching.Design and MethodsData were collected through a questionnaire designed to evaluate the perceived quality of the CPD intervention, identify the scientific areas teachers considered most relevant, and explore the reasons behind their preferences for experimental activities in Biology and Physics over Chemistry.ResultsWhen asked to identify the most relevant experimental activities, only 20 teachers selected Chemistry-related ones, whereas 58 chose Biology and 30 chose Physics. Analysis of the responses indicated that organisational barriers, limited access to materials in schools (both during and after the intervention), knowledge-related difficulties, and challenges in classroom implementation contributed to Chemistry being perceived as an abstract and complex subject.ConclusionThe findings highlight the persistent barriers faced by primary school teachers in adopting Chemistry-related experimental activities, suggesting the need for CPD initiatives to provide greater support, resources, and pedagogical strategies aimed at making Chemistry more accessible and meaningful at the primary level.

Abstract In a societal context where chemistry is often perceived negatively, it is essential to promote educational approaches that foster meaningful and engaging learning experiences from an early age. This study aimed to explore how the integration of storytelling and hands-on activities can contribute to primary school children's engagement and understanding of scientific concepts, leading to a more meaningful chemistry learning. The research was conducted in four primary schools in the northern region of Portugal, involving 237 third- and fourth-grade students in non-formal educational initiatives. A qualitative methodology was employed, based on the analysis of students' laboratory notebooks. The intervention consisted of a dramatized story from the book Hist & oacute;rias com Qu & iacute;mica [Stories with Chemistry], followed by three water-based hands-on activities addressing key chemical concepts: acid-base reactions, supersaturated solutions, and redox processes. Children's responses were analysed using framework theory, which enabled the categorization of their conceptual development. The findings showed that students' responses progressed from simple sensory observations and intuitive explanations to the construction of basic scientific models. High levels of participation, engagement, and enthusiasm were observed throughout the activities. These results suggest that combining storytelling with hands-on experimentation represents a promising pedagogical strategy for introducing chemistry concepts in early education and promoting a more positive and accessible image of this science.

Abstract Efficient and rapid detection of bacterial pathogens is crucial for food safety and effective disease control. While conventional methods such as PCR and ELISA are accurate, they are time-consuming, costly, and often require specialized infrastructure. Recently, electrochemical biosensors integrating graphene nanomaterials with bacteriophages-termed graphages-have emerged as promising platforms for pathogen detection, offering fast, specific, and highly responsive detection. This review critically examines all electrochemical biosensors reported to date that utilize graphene-phage hybrids. Key aspects addressed include the types of graphene nanomaterials and bacteriophages used, immobilization strategies, electrochemical transduction mechanisms, and sensor metrics-such as detection limits, linear ranges, and ability to perform in real matrices. Particular attention is given to the role of phage orientation, surface functionalization, and the use of receptor binding proteins. Finally, current limitations and opportunities for future research are outlined, including prospects for genetic engineering and sensor miniaturization. This review serves as a comprehensive reference for researchers developing phage-based biosensors, especially those interested in integrating carbon nanomaterials for improved electroanalytical performance.

Abstract The incorporation of lambda-cyhalothrin (LC) in lipid nanoparticles (LN) could be a sustainable strategy to increase its efficacy and decrease its hazard to the environment. The purpose of the present work was to perform the interaction between LC and LN after nanoencapsulation and to evaluate their effect on species from different aquatic trophic levels such as Aliivibrio fischeri, Raphidocelis subcapitata, Lemna minor, and Daphnia magna. LN loaded with LC (LN-LC) were produced by green and simple methodology without organic solvents using Precirol ATO5 (R) and Capryol 90 (R) as solid and liquid lipids, respectively, and soy lecithin and TEGO (R) Care as emulsifiers. The physicochemical interaction between LC and LN was assessed by differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), and X-ray, confirming that LC is associated with the lipid lattice of nano- particles, characterized by an amorphous matrix. The data from biological tests showed no or low toxicity of LNLC on the selected aquatic organisms. Thus, encapsulation in lipid-based nanoparticles may be a promising and sustainable choice for using this insecticide in agricultural practices, reducing its environmental risk.

Abstract Recent advances in neuromorphic resistive switching have enabled us to start emulating biological synapses and neurons. A liquid switching medium brings these devices even closer to brain-like systems, being soft and flexible. Here, we propose copper solution-based artificial synapses that show both nonvolatile and volatile, and excitatory and inhibitory behavior, without an electroforming step. Different copper sulfate solutions, concentrations, electrode materials, and spacings were studied. Low operation voltage was achieved for the aqueous solution, showing high endurance and data retention. By changing solvation to glyceline, a change between nonvolatile and volatile dynamics occurred, while maintaining neuromorphic behavior and enhancing stability. This shows, for the first time, both potentiation and depression in a volatile device. Our results are promising for bio-voltage neuromorphic memristor-based interfaces.

Abstract The purpose of this article is to present and discuss a historical house project that was transposed into virtual reality, to be preserved as digital cultural heritage. The Matosinhos House, in Portugal, is part of a residential project designed by the architect Alvaro Siza Vieira in 1955-56, is the historical house that was chosen as case study. The article displays the historical significance of the project, as well as the method applied to transpose it into virtual reality. The goal is to promote access to digital cultural heritage based on reliable and accurate interpretation of the collected data.

Abstract Extensive research has focused on films formed by pure ionic liquids (ILs). However, growing interest in IL mixtures and their synergistic properties presents new opportunities for targeted applications and fundamental scientific investigations. This study explores the morphology of films composed of mixtures of two ILs, [C2C1im][OTf] and [C8C1im][OTf], co-deposited via physical vapor deposition (PVD)/vacuum thermal evaporation. The primary objective was understanding how varying the IL ratio influences droplet formation, surface coverage, and overall film structure. Thin-film growth was examined on glass substrates coated with indium tin oxide (ITO) and ITO/glass surfaces coated with metallic films (Au and Ag). Film morphology was characterized using optical and high-resolution scanning electron microscopy (SEM), while elemental composition was analyzed via X-ray photoelectron spectroscopy (XPS). The results show that IL mixture morphology is strongly influenced by both IL composition and substrate type. Increasing [C8C1im][OTf] content led to larger microstructures due to improved wetting, particularly on Au surfaces, resulting in nearly fully coalesced films. Metallic surfaces near ITO significantly impacted droplet behavior, with ILs exhibiting a strong affinity for metals, especially when the long-chain IL dominated the mixture. The IL-assisted crystallization of rubrene, a high-performance organic semiconductor (OSC) that typically exhibits poor crystallinity when deposited via PVD, highlights the potential of IL mixtures to enhance organic film quality. X-ray diffraction (XRD) confirmed that [C2C1im][OTf] and [C8C1im][OTf] mixtures significantly improved rubrene crystallinity, demonstrating their potential to create an optimal environment for OSC solubility and crystallization. © 2025 American Chemical Society.

Abstract The impact of nanostructuration on the transport properties of ionic liquids (ILs) was explored by a systematic and high-resolution study of the temperature dependence of the viscosity and electrical conductivity of seven ILs homolog series: [C(n)C(1)im]BF4, [C(n)C(1)im]PF6, [C(n)C(1)im][OTf], [C(n)C(1)im][FAP], [C(n)C(1)im][NTf2], [CnC(1)pyr][NTf2], [Cnpy][NTf2]. The increase of the alkyl chain length was found to increase the viscosity and decrease the molar conductivity due to a reduction of the overall mobility of the liquid and enhancement of the van der Waals interactions. The temperature dependency of transport properties was fitted to the Vogel-Fulcher-Tammann equation (VFT), and the energy barrier and pre-exponential coefficients were derived. The obtained results highlight the trendshift (n = 6-7) in the profile of the transport properties, which is a reflection of the intensification of nanostructuration and describes the transition from a liquid with a strong ionic character to a nanostructured liquid dominated by the hydrophobic domain. The derived energy barriers were found to correspond to around 0.2-0.35 of the cohesive interactions of the ionic liquids, with the spherical anions BF4- and PF6- showing a higher fraction than the more stretched and larger anions, such as NTf2. This fraction was found to not be affected by the alkyl chain length. The increase of the nonpolar region was also reflected in a more pronounced deviation from the ideal Walden relation. This highlights the increased complexity of the electric conductivity when compared with viscosity due to the heterogeneity of charge distribution, revealing the impact of ionic surface-volume ratio and anion-cation size ratio.