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- Assessment of Rhodopirellula rubra as a supplementary and nutritional food source to the microcrustacean Daphnia magnaPublication . Marinho, Maria da Conceição; Lage, Olga Maria; Sousa, Carla D.; Catita, José; Antunes, Sara C.The daily use of the planctomycete Rhodopirellula rubra as an alternative or supplementary food source for Daphnia magna and its feasibility in the nutrition of transgenerational populations were studied. The life history parameters, fatty acids (saturated, mono- and polyunsaturated; SFAs, MUFAs and PUFAs), glycogen and protein contents of organisms during feeding assays and of the first generation were analysed. An increase in the yields of D. magna with the increase of the cell concentration of R. rubra was evident, but overall, bacteria supplied as the only food source was nutritionally insufficient as observed for all the parameters analysed. However, when R. rubra was added as supplement to the microalgae Raphidocelis subcapitata a significant improvement in the life history parameters was observed namely in the reproductive output and the somatic growth rate. The identified SFAs, MUFAs and PUFAs were the fatty acids more abundant in daphniids, and the feed regimens influenced daphniids fatty acid profiles. Additionally, the mixed diet resulted in a larger number and size of offspring in the different F1 broods as also observed with the results of F0 generation. The pink colouration present in D. magna body and eggs confirmed that bacteria were absorbed, the pigment(s) retained and passed on to the next generation. Our results showed that R. rubra can play an essential role in D. magna diet as a nutritional supplement showing potential biotechnological applications.
- Editorial on special issue “Lipid nanosystems for local drug delivery”Publication . Catita, José; Lopes, Carla Martins
- Challenges in nanomaterials characterization - from definition to analysis (capítulo 1)Publication . Catita, JoséNanomaterials have outstanding properties and have several applications, ranging from foods, cosmetics, pharmaceuticals to energy, construction, etc. As with all novel products, the benefits of nanomaterials use must be weighed against its health and environmental impact. They have different origins, natural, incidental, or engineered, they are widespread, and they need to be classified and characterized for various purposes, including nanotoxicology studies and risk assessment, workplaces and environment safety evaluation, consumer products evaluation, as well as manufacturing process control. To properly characterize nanomaterials, a consensual definition of nanomaterial is needed, and several analyses using the available characterization techniques must be performed. Various properties are relevant in the characterization process and many of them, namely size, are still a challenge that the research community is facing. The measurement of physical and chemical properties is very important in the case of nanomaterials. In view of this, in this chapter, available analytical techniques are reviewed based on nanomaterials classification, regulatory demands and toxicology assessment. Additionally, some of the current major challenges and gaps in nanomaterials characterization are identified and listed.
- Nanostructured lipid carriers enriched hydrogels for skin topical administration of quercetin and omega-3 fatty acidPublication . Lúcio, Marlene; Giannino, Nicole; Barreira, Sérgio; Catita, José; Gonçalves, Hugo; Ribeiro, Artur; Fernandes, Eduarda; Carvalho, Isabel; Pinho, Hugo; Cerqueira, Fátima; Biondi, Marco; Lopes, Carla MartinsChronic skin exposure to external hostile agents (e.g., UV radiation, microorganisms, and oxidizing chemicals) may increase oxidative stress, causing skin damage and aging. Because of their well-known skincare and protective benefits, quercetin (Q) and omega-3 fatty acids (ω3) have attracted the attention of the dermocosmetic and pharmaceutical sectors. However, both bioactives have inherent properties that limit their efficient skin delivery. Therefore, nanostructured lipid carriers (NLCs) and enriched PFC® hydrogels (HGs) have been developed as a dual-approach vehicle for Q and/or ω3 skin topical administration to improve bioactives’ stability and skin permeation. Two NLC formulations were prepared with the same lipid composition but differing in surfactant composition (NLC1—soy lecithin and poloxamer 407; NLC2—Tween® 80 and dioctyl sodium sulfosuccinate (DOSS)), which have an impact on physicochemical properties and pharmaceutical and therapeutic performance. Despite both NLCs presenting high Q loading capacity, NLC2`s physicochemical properties make them more suitable for topical skin administration and ensure longer colloidal stability. Additionally, NLC2 demonstrated a more sustained Q release, indicating higher bioactive storage while improving permeability. The occlusive effect of NLCs-enriched HGs also has a positive impact on skin permeability. Q-loaded NLC2, with or without ω3, -enriched HGs demonstrated efficacy as antioxidant and photoprotective formulations as well as effective reduction in S. aureus growth, indicating that they constitute a promising approach for topical skin administration to prevent skin aging and other damaging cutaneous processes.
- Formulation, characterization, and cytotoxicity evaluation of lactoferrin functionalized lipid nanoparticles for riluzole delivery to the brainPublication . Teixeira, Maria Inês; Lopes, Carla Martins; Gonçalves, Hugo; Catita, José; Silva, Ana Margarida; Rodrigues, Francisca; Amaral, Maria Helena; Costa, Paulo C.Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with a very poor prognosis. Its treatment is hindered by a lack of new therapeutic alternatives and the existence of the blood–brain barrier (BBB), which restricts the access of drugs commonly used in ALS, such as riluzole, to the brain. To overcome these limitations and increase brain targeting, riluzole-loaded nanostructured lipid carriers (NLC) were prepared and functionalized with lactoferrin (Lf), facilitating transport across the BBB by interacting with Lf receptors expressed in the brain endothelium. NLC were characterized with respect to their physicochemical properties (size, zeta potential, polydispersity index) as well as their stability, encapsulation efficiency, morphology, in vitro release profile, and biocompatibility. Moreover, crystallinity and melting behavior were assessed by DSC and PXRD. Nanoparticles exhibited initial mean diameters between 180 and 220 nm and a polydispersity index below 0.3, indicating a narrow size distribution. NLC remained stable over at least 3 months. Riluzole encapsulation efficiency was very high, around 94–98%. FTIR and protein quantification studies confirmed the conjugation of Lf on the surface of the nanocarriers, with TEM images showing that the functionalized NLC presented a smooth surface and uniform spherical shape. An MTT assay revealed that the nanocarriers developed in this study did not cause a substantial reduction in the viability of NSC-34 and hCMEC/D3 cells at a riluzole concentration up to 10 μM, being therefore biocompatible. The results suggest that Lf-functionalized NLC are a suitable and promising delivery system to target riluzole to the brain.
- Development of lipid-based colloidal nanocarriers for topical application of acyclovirPublication . Silva, Juliana; Lopes, Carla Martins; Catita, José; Real Oliveira, Maria Elisabete; Lúcio, Marlene
- Miconazole-loaded Nanostructured Lipid Carriers (NLC) for local delivery to the oral mucosa: improving antifungal activityPublication . Mendes, A.I.; Silva, Ana Catarina; Catita, José; Cerqueira, Fátima; Gabriel, C.; Lopes, Carla MartinsMiconazole is a widely used antifungal agent with poor aqueous solubility, which requires the development of drug delivery systems able to improve its therapeutic activity. For this purpose, a miconazole-loaded nanostructured lipid carriers (NLC) dispersion was prepared and characterized. Further, the dispersion was used to prepare a NLC-based hydrogel formulation proposed as an alternative system to improve the local delivery of miconazole to the oral mucosa. NLC dispersion showed particles in the nanometer range (≈200 nm) with low polidispersity index (<0.3), good physical stability and high encapsulation efficiency (>87%). A controlled miconazole release was observed from NLC and NLCbased hydrogel formulations, in contrast to a commercial oral gel formulation, which demonstrated a faster release. Additionally, it was observed that the encapsulation of miconazole in the NLC improved its antifungal activity against Candida albicans. Therefore, it was demonstrated that the encapsulation of miconazole in NLC allows for obtaining the same therapeutic effect of a commercial oral gel formulation, using a 17-fold lower dose of miconazole.
- Omega 3 and resveratrol loaded lipid nanosystems for potential use as topical formulations in autoimmune, inflammatory, and cancerous skin diseasesPublication . Caldas, Ana Rita; Catita, José; Machado, Raúl; Ribeiro, Artur; Cerqueira, Fátima; Horta, Bruno; Medeiros, R.; Lúcio, Marlene; Lopes, Carla MartinsResveratrol (RSV) and omega 3 (ω3), because of their biological favorable properties, have become subjects of interest for researchers in dermocosmetic and pharmaceutical industries; however, these bioactives present technological limitations that hinder their effective delivery to the target skin layer. To overcome the stability and skin permeation limitations of free bioactives, this work proposes a combined strategy involving two different lipid nanosystems (liposomes and lipid nanoparticles) that include ω3 in their lipid matrix. Additionaly, RSV is only encapsulated in liposomes that provid an adequate amphiphilic environment. Each formulation is thoroughly characterized regarding their physical–chemical properties. Subsequently, the therapeutic performance of the lipid nanosystems is evaluated based on their protective roles against lipid peroxidation, as well as inhibition of cicloxygenase (COX) and nitric oxid (NO) production in the RWA264.7 cell line. Finally, the lipid nanosystems are incorporated in hydrogel to allow their topical administration, then rheology, occlusion, and RSV release–diffusion assays are performed. Lipid nanoparticles provide occlusive effects at the skin surface. Liposomes provide sustained RSV release and their flexibility conferred by edge activator components enhances RSV diffusion, which is required to reach NO production cells and COX cell membrane enzymes. Overall, the inclusion of both lipid nanosystems in the same semisolid base constitutes a promising strategy for autoimmune, inflammatory, and cancerous skin diseases.
- Comparison of neutral lipid fatty acids composition in organisms from different trophic levelsPublication . Lage, Olga M.; Antunes, Sara C.; Marinho, Conceição; Catita, JoséThe profiles of total fatty acids (TFAs) and the neutral lipid fatty acids (NLFAs) were compared for the bacterium Rhodopirellula rubra and the alga Raphidocelis subcapitata (conventional food source for Daphnia magna). D. magna NLFAs were assessed when this crustacean was fed with bacterium and alga, individually or in combination. After NLFA extraction, the profiles of the various organisms were characterized by gas chromatography. Results evidenced the relevance of the different composition of the fatty acid (FAs) fractions in the different organisms, R. rubra and R. subcapitata. In these species, the NFLA analyses revealed high amounts of long chain FAs (C19). The FA profile of D. magna was influenced by the different diets provided although the preferred diet was the alga. D. magna showed the capacity to adapt to the available food resources as it defines its FA profile according to its needs, namely for the long chain FAs (C19).
- Potential of FTIR spectroscopy applied to exosomes for Alzheimer’s disease discrimination: a pilot studyPublication . Soares Martins, Tânia; Magalhães, Sandra; Rosa, Ilka Martins; Vogelgsang, Jonathan; Wiltfang, Jens; Delgadillo, Ivonne; Catita, José; da Cruz e Silva, Odete A.B.; Nunes, Alexandra; Henriques, Ana GabrielaAlzheimer's disease (AD) diagnosis is based on psychological and imaging tests but can also include monitoring cerebrospinal fluid (CSF) biomarkers. However, CSF based-neurochemical approaches are expensive and invasive, limiting their use to well-equipped settings. In contrast, blood-based biomarkers are minimally invasive, cost-effective, and a widely accessible alternative. Blood-derived exosomes have recently emerged as a reliable AD biomarker source, carrying disease-specific cargo. Fourier-transformed infrared (FTIR) spectroscopy meets the criteria for an ideal diagnostic methodology since it is rapid, easy to implement, and has high reproducibility. This metabolome-based technique is useful for diagnosing a broad range of diseases, although to our knowledge, no reports for FTIR spectroscopy applied to exosomes in AD exist. In this ground-breaking pilot study, FTIR spectra of serum and serum-derived exosomes from two independent cohorts were acquired and analyzed using multivariate analysis. The regional UA-cohort includes 9 individuals, clinically diagnosed with AD, mean age of 78.7 years old; and the UMG-cohort comprises 12 individuals, clinically diagnosed with AD (based on molecular and/or imaging data), mean age of 73.2 years old. Unsupervised principal component analysis of FTIR spectra of serum-derived exosomes revealed higher discriminatory value for AD cases when compared to serum as a whole. Consistently, the partial least-squares analysis revealed that serum-derived exosomes present higher correlations than serum. In addition, the second derivative peak area calculation also revealed significant differences among Controls and AD cases. The results obtained suggest that this methodology can discriminate cases from Controls and thus be potential useful to assist in AD clinical diagnosis.